Comments so far are not discussing what makes this light rail “very” light, so here’s an excerpt. The project claims to cost half of “normal” light rail.
> The vehicle is battery-powered, eliminating the need for overhead wires. It features an innovative turning system, enabling it to handle 15m radius curves. This allows for installation in tight corners within the existing highway. The Council intends for it to operate at a high frequency, providing a turn-up-and-go service. The vehicle has a capacity of 56, is comfortable and has low floors to enable passengers to embark and disembark easily. The vehicle has been developed to allow autonomous operation in future.
> The new track is laid just 30cm within the road’s surface, minimising the need to relocate pipes and cables, which is time-consuming and expensive. It achieves this by leveraging cutting-edge materials science, while still utilising standard rail parts to ensure ease of manufacture.
It’s fairly obviously designed to avoid the issues which almost caused the cancellation of the new Edinburgh tram — spiralling costs caused by the need to move existing utilities under the deep track base. That crisis was probably as much to do with a badly formed set of contracts as with the technical issues themselves, but it’s still worth designing out.
These things are tiny! I've traveled in larger airport shuttles.
It feels like that's putting this into a really awkward place in the tradeoff space. Trams work because they can scale higher than buses. That scale comes at the cost of more up-front infrastructure, much less flexibility, and needing dedicated lanes. So cities don't have trams everywhere, but they're only installed on routes that can support the scale.
For these you still have the up-front investment (just less of it) and inflexibility, but don't get the efficiencies of scale due to how small the capacity is.
Is this really just a bet that they can get autonomous tram-driving on city street approved a decade+ sooner than autonomous buses?
Tiny might make sense if they are running every 2 minutes and thus getting their capacity via frequency. However there is no reason to think they will do that. (if they were running anywhere near that frequent overhead wire would be a lot cheaper than a battery on every tram)
Not really because buses get stuck in traffic all the time because there’s a point where they need to share roads with cars. Once you spend the money on segregating buses entirely, you’re at the same level as the tram line.
Also, because of the expensive infrastructure that can only be used by trams, there’s a permanence there that prevents future politicians from ripping it out to put more cars on for a quick political win with drivers.
Going back to point 1: having a line means that any route needs to be properly planned because you never have an escape hatch of “just stick them on the road.” Example: where I live, the council installed a bus lane and a cycle lane. Where it pinches in (planning fuck up), it dumps all the traffic into a shared route with 2 roundabouts and 5 exits, each with an insane amount of traffic coming to or from them. Buses that are forced to use that route are always late. It takes me just as long to drive as it does to take the bus, faster if you factor in me waiting for a late bus.
The Nottingham tram, not far from Coventry, usually only shares road with cars in the city centre which is mostly pedestrianised. So mostly avoids commute traffic.
> Not really because buses get stuck in traffic all the time because there’s a point where they need to share roads with cars.
Like many tram lines, CVLR is being laid in-road and not segregated. In fact, while not mentioned here, the it's 15 m turning radius is so important is because it's planned to traverse roundabouts in-lane.
That is in the article. The intention is a frequent, arrive and go service. Maybe every 2, 5, 10 minutes, whatever the actual details will be, that is the goal.
I didn't really mean that they needed higher capacity. If they had the passenger volume to justify such high intervals, they'd already have real trams.
But rather, this is giving up the benefit trams have over buses, without gaining any new edge to replace it. So why is it a good tradeoff? And why now, not 20 years ago?
The autonomous driving angle is the only idea I have.
Bus Rapid Transits can operate at frequencies of about 10 seconds per bus. Obviously they're highly parallelised to achieve that and have special infrastructure to enable it like dedicated stations and pedestrian access, so it's not just "a bus", but bus-based systems are how many of the very highest-throughput public transportation lines function, with up to 35000 people per hour per direction with three digit numbers of buses per hour.
For comparison, the most frequent London underground service is 100 seconds per train and the system moves about 50k passengers an hour (based on a 21% increase representing 10k passengers, I couldn't find a direct figure), presumably that being both directions.
I'd assumed the point of them was that you can take the several cars of a tram and split them up to have more frequent services. Though I suppose this would compound with the cost of having a driver on each car, potentially cancelling some of the gains from cheap installation. As for the point of automation, I think the tram can probably be a lot easier than the bus because of the human factor. It seems safer, so legislators will be more willing to legalise it and residents less likely to complain. Also, you've got rails in the road that clearly mark the route of the tram which make it more visible than an automated bus. Most of these automated taxi companies still have a human supervising the process, and I imagine that could be employed here to good effect and with fewer or faster manual interventions than would otherwise be needed.
Even if all that falls through, I'm not gonna complain about it. We sorely need more public infrastructure in the UK. Even if an experiment like this fails, at least you actually get a tram line and experience out of it. Much better than a project which sucks up million then gets cancelled. (Cough cough HS2.)
With computerized control and a comms link between the vehicles, you could probably have one vehicle follow 1m behind another, so they are effectively a train. If you still have a driver at all, you only need one in the front vehicle.
I don't think you could do that for CVLR specifically as it's not segregated from traffic and the second car would have to react individually to vehicles, pedestrians, roundabouts, etc.
If it's really just 1m behind, it doesn't need to respond individually to anything except pedestrians. And you can solve that with some extensible tapes that actually do connect the vehicles to prevent pedestrians walking between them.
Trams don't actually scale higher than busses; the highest ridership BRTs have far more ridership than the highest ridership light rail. The key thing that makes it work is having a dedicated right of way. I expect busses get a bad rap as a scaled transit solution mostly because they have to share the roads so often. But it's indeed an advantage of light rail that it's a lot harder to make that mistake with it.
Those BRTs will have lower passenger/operator ratios though since trams tend to be bigger than articulated buses and are frequently coupled together for busier routes.
I definitely agree that the dedicated right of way is the main thing. It's why some of San Francisco's trams are so slow outside of the city centre (where they run in a tunnel) and why Manchester's trams are so slow through the city centre (where they run at surface level sharing the street with pedestrians.)
Absolutely! I’ve used the Manchester Metrolink and it definitely slows down in the city centre. It does speed up a lot (and likely beats bus in rush hour) when you’re off the streets, which makes it an incredible commuter option!
Have recently read Gareth Dennis’ How Railways will fix the Future…
It’s a worthwhile read BTW
I suspect these are too small to carry a significant number of passengers per hour
They’ll also probably never be autonomous as the challenge with autonomous is less the driving and more with passengers getting on and off, getting trapped etc
Buses on dedicated lanes are OK indeed. However, buses are simply not as comfortable as trams: roads unless in tiptop shape are not as smooth as rail, and bus drivers always take corners too fast.
Having to hold on to something discards it from my preferred list of solutions.
A 15 meter turning radius is tight, but not revolutionary. San Francisco's MUNI system's tightest turns are 45 feet, or 13.7 meters. The newer vehicles are designed for that, and the old PCC cars had to be modified to allow the trucks some extra rotation. The turning loop on Embarcadero near Market is that tight. There is much wheel screeching when a PCC car goes through that loop, because wheels have to slip to turn that tight. But it works.[1]
Battery powered trams have real potential, now that batteries with 5 to 7 minute charging and large numbers of charging cycles are a thing. That's compatible with typical end of line holding times. Steel wheel on steel rail is low friction, and you get most of the energy used to go uphill back when you go downhill. This could work out.
> Steel wheel on steel rail is low friction, and you get most of the energy used to go uphill back when you go downhill.
If you were going up and down hills, would you still use steel wheel in steel rail unless you had some sort of cable to work with? I always thought the Muni did relatively level routes for that reason? The Lausanne m2 for example uses rubber (well, ideally you’d be able to just balance the train going up with the train going down, but that only works for simple inclines with limited stops). Actually, a battery powered rubber wheeled tram service on some sort of steep incline like SF’s cable car routes could get some wicked regen going down.
Even if level, they could still get some regen from making stops.
> A 15 meter turning radius is tight, but not revolutionary. San Francisco's MUNI system's tightest turns are 45 feet, or 13.7 meters.
Revolutionary as the turning circle will be used at speed with passengers to traverse roundabouts in-lane. CVLR doesn't need turning loops, as the vehicles can be driven from either end.
Besançon in France is one of the cheapest conventional tram schemes in Europe at €17.5m per km and €1.81 per tram (132 passengers). It’s a conventional tram track with overhead catenary wires: as standard as one can get with those things. Presumably in the UK the costs would be somewhat higher: France is a modern tram capital, with a lot of relevant talent and expertise available locally.
I haven’t found the projected figures for Coventry but it would be very, very awkward if they can’t beat the numbers above with a supposedly much cheaper track.
CVLR is projected to cost £10 MM per km, but we all know what projections are worth.
Still, there's no point comparing build costs between France and the UK as they're completely different cultures and jurisdictions. Instead, a more reasonable approach is to compare to recent similar project in the UK.
Edinburgh's tram covers 18.5 km and cost at least (they're still uncovering overruns years later) £1 BN. That's ~£50 MM or ~€60 MM per km. That's what CVLR should and will be benchmarked against.
Very good point. There’s also a potential for future upgrades. They may invest into catenary lines at some point, get rid of batteries and increase capacity inside vehicles. Or, switch to hot-swap batteries and increase vehicle turnaround and frequency. Or, they can switch to traditional concrete reinforcement for rails for future lines if they decide that the rails-on-slabs approach doesn’t work out as well as they hoped for. Their vehicles while custom-built are running on top of standard tram lanes, so they will be able to use traditional tram tracks, too.
VLRT seems gimmicky at first but the more I look at it the more sense it makes.
Everything old is new again: The Light Railways Act of 1896 also propsed rail lines built to less then mainline standards (often narrow gauge) to get transport links to otherwise unconnected locations. https://en.wikipedia.org/wiki/Light_Railways_Act_1896 comment edited because I fat finger editing the submit button
If overhead wires were the only advantage of light rail, why is anyone using light rail instead of trolleybuses?
The answer is of course that rails provide major advantages on their own, primarily by allowing vehicles to travel much more efficiently thanks to the low friction of running steel wheels on steel tracks
There's various possible reasons. Less pollution from tire wear and the possibility to lay tracks across grass to create relatively ecological dedicated lines so the carriages don't get stuck in traffic are two options that spring to mind immediately.
“Thanks to the very low friction between the steel wheel and steel rail, railways can move a load using as little as 15% of the energy that road haulage needs.”
Gadgetbahn - a derisive term transit advocates use for something that claims to be innovative but in fact doesn't do anything not thought of before and doesn't solve any problems.
They make all kinds of claims that don't stand up to over 100 years of history running trains. The claim they are innovative, but there is nothing new here, and no evidence they have looked at the real problems of transit systems. Someone is going to make a lot of money on this at the expense of the community that loses.
Trains have been around for a long time. You can buy all the parts you need for a good system off the shelf. You won't be saving money by designing something new, you just waste money on engineers to design something and then lose the scale factors you could get from buying the same thing as everyone else. If you buy the same thing as everyone else that means there will be a market for spare parts and thus in 20 years when (not if!) something breaks you can keep the system running.
Yes overhead wires are expensive - but they are a rounding error compared to track. Batteries are expensive too, and you have to buy a lot of them. Batteries need to be recharged which means these trams will be out of service often so they have to buy a lot more so that when one is out of service for charging the others can work. (you still need a few extra for maintenance, but battery charging is more common so you need a lot more)
If you want to build a train the best way to save money is to build exactly the same as everyone else does: standard off the shelf trains, running on standard off the shelf rails, and standard off the shelf overhead rail. If you want to innovate make sure that everyone is fluent in Spanish, Turkish, Korean, or Italian - because places where those languages are spoke build and run trains much cheaper than other places you can think of so you want to learn from them. (note that French or Japanese are not on the above list - while those areas do cheaper than English speakers, they are still expensive)
I'm not sure about the UK, but in the US most of the cost blowout for trains seems to be in stations, so focus all your innovation there: don't make them monuments to how much money you can spend. (The UK has cost problems almost as bad as the US, but I'm not aware of any study on where the issues come from, while at least in the US there are studies).
Unfortunately the Coventry VLRT is all about aesthetics over actually transit benefits. If the they were concerned about being useful transit the vehicle would have capacity higher than an articulated bus. Instead the main benefit of Trams/LRT over buses, capacity, is sacrificed leaving no real benefits. You can see the same thing with the Obama ere streetcars in the USA where most of them proved no real benefits over the buses the run alongside them but at least they retained the capacity even if it was never needed.
Finding the right balance of capacity is a tough problem because cities generally intend to grow, and it's expensive to to have unused capacity. As well if you actually build for that, people will say the project is a failure since ridership will seem low.
London’s DLR is a gadgetbahn. For all its obvious limitations it’s been quite successful. Lots of new stations, lots of expansions, decent integration with traditional rail. VLR would work similarly.
Well the standard response to this kind of "do it the way everyone does it" is "... change has to start somewhere". It's hard to tell, without hearing a report from a council of open-minded-rigorous-experts, whether some claimed innovation on a particular is actually worth doing or not---but certainly neither of "innovation is always good" and "innovation never works" is true.
Anyway everyone is pretty sure that that something is wrong with the standard train economics as you describe them, because if there wasn't something wrong with it there'd be a lot more trains. I can't tell from the site, or from your comment, if this is the solution, or even worth doing as an experiment... but "don't change anything ever" doesn't strike me as productive either.
The problems with trains are well known and they are not addressing them. There might be unknown problems an well, but the things they are talking about have already been tried and failed for reasons they don't seem to be aware of.
Innovation should require some knowlegde of what is already done - otherwise you invent square wheels.
They're addressing one problem, and one problem only.
Adding a bus line isn't sexy, even bus rapid transit (BRT) sounds like a wet fart. They work, they can work extremely well, but nobody gets excited about it.
This thing is just like a monorail; something worse than a bus but that sounds sexier.
Interestingly, in public policy, how sexy something sounds tends to be directly proportional to how much the public is willing to spend. It's often easier to get 10-100x the money of a bus for a rail link.
You’re talking about trains, but this is about trams. The design constraints of building into an existing and very dense road network are complex.
I agree with much of your sentiment, and hope that the Coventry council is being challenged in these sorts of ways, but at the same time I recognise that each city is going to have quite different requirements for trams driving down the roads in its centre.
Perhaps a better push back is: why isn’t this just a better bus network?
They operate in completely different scenarios. They’re the same shape, but they’re a different set of hardware, constraints, accessibility, need to be scheduled in a different way to account for traffic, different safety concerns, different signalling systems, different distances, different surroundings.
Again I sorta see what you mean, but feel you’re massively over simplifying this.
(For me, the big thing about trams and trains and subways, etc is that the track is a kind of social construct - the track tells me that eventually a vehicle will come for me - no need to really worry about timetables, etc. A bus, a bus may come, maybe it won't. It's all psychoillogical but it's there the same.)
The fundamental operational principle is different. Trams operate (typically, on street running sections) on sight - they are responsible for monitoring traffic, and stoping if necessary. Contrast with the block-based approach used for trains, especially in combination with Euro-style positive train control systems.
The second sentence is partially true: they do have different modes of operation.
But no, they don’t face entirely the same issues. Trains should hopefully never routinely encounter cars sharing their track and they don’t have to make tight turns to follow existing roadways.
Well then there's no difference between overground and underground trains. But it's pretty clear that there are different issues facing building new metro lines.
In Australia, highest cost is buying up required land and construction of buildings. We spent ~100mil USD on a single, open air platform for a line extension of exactly that one station. It was about 5 km of extra track. It is amazing we have any trains at all.
You’re grossly oversimplifying and ignoring knock on effects.
Eliminating overhead wires isn’t about cost. It’s about being able to build in existing urban areas that don’t want high voltage live wires everywhere, and likely already have above ground infrastructure they would interfere with.
For me, trams have a much more comfortable ride. The lack of pitch and roll reduces a lot of motion sickness and the rails are obviously a lot smoother than paved surfaces.
There’s nothing stopping a road from being smooth but, logistically, there’s clearly no reason to rush to repair roads when they deteriorate. That means potholes get tolerated, potholes means suspension, and both of those mean bus-like rides instead of suburban light rail rides.
Railway track has to be flat. Anything less than perfect is intolerable so it tends to hold its maintainers to a higher bar.
As I understand it tracks do a much better job of spreading the load than asphalt which makes it much more durable.
I've found the new battery buses to be far more comfortable to ride in than older diesel buses since they remove the vibration when idling. The extra weight might mean more potholes to repair though.
One advantage is that light rail encourages transit oriented development.
The fact that buses are so flexible and easily (and cheaply) rerouted makes developers less likely to build developments that rely on access to transit, but once a community spends a hundreds of millions of dollars on a light rail line, they know it's there for the long term.
That's sort of the popular wisdom, but rails don't guarantee it will be there for the long run. DC recently announced that they're replacing their light rail with buses:
I agree with him that in order to endure and justify a permanent operating subsidy a transit service needs to be useful and used by many people. Most American light rail doesn't meet that bar.
Interesting piece, thanks. I also enjoyed his piece "Streetcars: An Inconvenient Truth." His argument is based on length, speed and cost; the main point is that a technically equivalent bus would often be cheaper and thus could be run on a longer, more useful route. If you look at the hundreds of millions spent on DC Streetcar and its limited utility, this all starts to look quite obvious. So why did we do it?
I think there is another aspect that usually goes unstated, which is the vibes. If you're a mayor you want to build a tram. If you're a tourist you want to ride a tram. If you're a prospective resident you want to live near a tram. Yes, it's smoother and yadda yadda, but really it's because it has more sex appeal. A technically equivalent bus may well be _technically_ equivalent but could never be truly equivalent. Nobody would write a play entitled A Technically Equivalent Bus Named Desire. In a way, spending money on a tram is similar to spending money on parks or flowers or public art. And so we will spend the money; and we will build the streetcar; and damn the technical equivalence.
I wonder what the world would be like if we were honest with ourselves.
I've seen that claim, but places that run good bus service for decades see plenty of transit oriented development. (most of those places also have subways though. The other options seems to bad bus service which won't get transit oriented development but bad service is enough to explain why)
You and I are well aligned on a lot of things - but in general, buses do not result in TOD. There are some exceptions, but they are very much exceptional. Trains generally do result in TOD because the people pushing for TOD get to try over and over again.
As a city grows, it's common for the transit system to evolve from direct bus routes to trunk lines supported by local buses. Maybe there was a good bus service to the city center when you bought your home. But now the buses only go to the nearest transit hub, because there is no space for all the buses in the city center anymore. While the average quality of transit may have improved, your services are slower and less convenient than they used to be.
That's sad but I can see that. Maybe more with train and metro stations though than light rail that often makes little difference to commute times vs a bus.
Physically easier. Often not politically easier. Voters are often more willing to pay for a metro than lose a lane from cars. We ran into this in Seattle over and over.
A bus only lane is also a vehicle lane that is sitting empty a good part of the time.
Not really that efficient...
And, as has been rediscovered about 200 times in Southern California (by the drivers, not by the sstate government), you can add additional lanes almost indefinitely, and it doesn't really help congestion that much.
This is one of these sets of information that don't seem to make sense until you fit it all together.
Busses aren't much more efficient when riding down a lane than lower occupancy vehicles, but streets aren't bottlenecked by their roads, they're bottlenecked by their intersections. The key advantage of a bus is at the intersection. A bus holds the intersection for far less time than the equivalent passenger capacity of cars.
The problem bus lanes try to solve is dominantly that without them the traffic advantage of people riding busses mostly goes to people not riding busses, and this makes for a pretty terrible incentive structure. Busses are intrinsically disadvantaged against cars (schedules, uncertainty, routes), so if you don't help them, then people will prefer to drive. Bus lanes internalize the externality.
No less efficient than track sitting empty most the time.
And your bus only lane has a lot more options. If there is a major disaster you can divert other traffic (not necessarily all traffic though that is an option) into it which might be a useful compromise at time. If you need to repair your bus only lane you just divert the bus to regular traffic. For that matter most places there isn't any traffic and so a bus in mixed traffic has no downsides thus not costing you that whole lane (or track), just build the bus-only lane where it is needed.
Trains are a good thing when they do something a road cannot. However the common bus can be just as good for much less. If you have the money and want good service and ride quality the bus can do it too, and typically for much less cost than a train.
Trains are good where they don't mix with traffic (meaning elevated or underground) because they can then be automated (and also faster). Alternatively a train can hold more people, so if you are in the rare situation where a 100 passenger bus every 5 minutes can't handle the passengers a train is good. Most of the time though you are not in either situation and so a bus can do everything a train can.
I live in a city with trams in the UK and that’s not how it works. There are sections that run on dedicated train lines, and sections where it runs on the street. Where it runs on the streets, priority is given over cars by switching traffic lights to red. Once the tram has passed onto the road it switches back to green so you can end up following the tram in your car.
> No less efficient than track sitting empty most the time
Unless the track is just in a regular lane that can be full of cars/busses/trucks whenever there isn’t a light train. Like how trams work in most of the world
I think you've been lied to with that highly misleading statistic. The 3000 for cars is actual (though I'm skeptical of that now too), while the 30,000 for buses is theoretical. "While a typical traffic lane carries approximately 3,000 people in 2,000 cars each hour, the XBL lane can carry over 30,000 people in 700 buses during that same time period." http://fourthplan.org/action/highway-congestion
That doesn't seem unreasonable for the Lincoln tunnel. Rush hour buses are pretty full, 50 on each seems pretty reasonable - everyone got a seat!
> Now the XBL handles 1,850 buses that carry more than 70,000 passengers from 6 a.m. to 10 a.m. each weekday, which comes to 600 buses an hour. The bus lane operates at its maximum capacity for 90 minutes of its four-hour operation.
Here in San Francisco along Mission St we have about 20 articulated buses an hour in each direction. These have a planning capacity of 94, 85% load standard 80, 125% crush capacity 119 according to https://www.reddit.com/r/AskSF/comments/445xdg/what_is_the_m....
While mostly a bus and taxi lane Mission St allows local traffic within each block so buses are still a minority of the vehicles in the lane.
Meanwhile the main 2 lanes in each direction street nearby has 1020 vehicles an hour in the peak direction. At 1.6 people per vehicle that's only about 830 people per lane at rush hour. So even at 'standard capacity' the buses in a regular city street not completely dedicated bus lane carry double the number of people. (From experience I suspect it is somewhat more than that.)
That's a bus every 5.1 seconds. In a single lane. (and at 30mph it'll take 1.5 of that 5 seconds just for the bus itself to pass. That's very marginal braking distance).
The article I quoted to which you are replying suggests 600 busses an hour. I don't think that is unreasonable for a dedicated highway lane into a bus terminal. There's a nice picture of it here: https://abc7ny.com/port-authority-lincoln-tunnel-technology-...
> Also, 1850 / 4 is 453, not 600.
Quoted in the post you are replying to:
> Now the XBL handles 1,850 buses that carry more than 70,000 passengers from 6 a.m. to 10 a.m. each weekday, which comes to 600 buses an hour. The bus lane operates at its maximum capacity for 90 minutes of its four-hour operation.
I read that as they reach the maximum capacity of 600 buses an hour only for the 90 minutes of rush hour. Across the 4 hours it operates each bus averages 38 passengers (70000/1850). It seems reasonable to assume that the rush hour buses are more packed given they are looking at ways to increase capacity and have you ever taken a rush hour bus in a big city?!
From the picture linked above these seem to be 53 seat coaches for longer distance routes rather than city buses which would carry more passengers with some standing. 50 * 600 = 30,000. It's in the ballpark!
> A bus only lane is also a vehicle lane that is sitting empty a good part of the time.
A rail track for the same route sits empty just as much.
> you can add additional lanes almost indefinitely, and it doesn't really help congestion that much.
I don't think adding bus-only lanes would have that effect. Adding lanes for private vehicles reduces congestion, which encourages people to move to places along the route until the congestion reaches the previous barely-tolerable level (as I understand it).
Don't measure vehicles per hour. Measure people per hour. Also letting the cars in means more people use cars means you soon need another lane.
Other advantages: people who don't drive, which includes children can get about. Lots of public transport can compensate alot for un walkability of suburbia.
> A bus only lane is also a vehicle lane that is sitting empty a good part of the time.
You can make the same argument (in terms of space) about a train track. The real advantage of trains (light or heavy) is permanence. It's easy for the next government to remove the bus lanes because "OMG too much traffic, one more lane will fix it." It's much more difficult to rip out a rail line and convert it to a road.
I wouldn't be planning any fixes infrastructure transit programs that didn't have an ROI in the next 7 years. It will be hard for anything to compete with the efficiency of Waymo.
Single passenger cars still have a problem with density even if there's no need for a driver. Combining multiple people into one trip can help, but also lessons the utility of Waymo if riders have to go out of their way to pick up additional passengers.
Getting 1000 people downtown could be up to 2,000 Waymo trips (one trip to drop off the worker, another trip for the car to go back out to pick up another passenger). While one of these 56 passenger very light rail cars can do it in 18 trips. A light rail vehicle like the Siemens trains used in San Francisco can carry up to 200 people at crush loads, so that's 5 trips.
You mean it's very difficult to compete with a company that is massively subsidised by public infrastructure? That's what really killed freight rail in most of Europe, make the train companies pay for track maintance (often the rail companies even want this because it keeps competition out as well), while trucks atpapy very little of the cost they impose on the public (i.e. much higher road usage, causing most of the traffic issues).
The big AV transit efficiency gains* can only happen when nearly all human drivers are removed from the road. Alas, that's at least 20 years ahead of now**, or more (e.g. if tech stalls for some reason, though I consider it unlikely). Otherwise they'd be limited by having to account for human drivers and that limits speed and throughput enough so other solutions are a must.
* Think having much higher speed limits (as far as humans are concerned, nonexistent), or mass coordinating movement over the entire traffic.
** We can reasonably estimate the minimum without bothering to ask how fast the tech will improve: Even if the tech were available now, think about fleet replacement costs which no one group would be too eager to pay. Best case, it's the typical 'make a concentrated pressure group lose for societal benefit' and we know how that politics goes. It will happen, but slowly.
*** Another thing to account for is that there's no good reason to design an AV car like a normal car, and there'll be some iteration time over that too.
True, but this can be compensated for. Current vehicle design is based on human-operated gas vehicles - so it better be aerodynamic (to save gas), and a human needs to be in the front (to see) with only a glass to separate, and it needs a particular stopping action (again a consequence of carrying humans without enough separation). This has unfortunate implications for noise and stopping distance. Electric-powered AV can have creative designs to enable much quicker (yet safe) stopping action, an action which AV would also make rarer.
If this were true, cities would have abandoned mass transit for taxi system decades ago. The requirement for there to be a warm body driving a taxi isn't among the prime causes of its inefficiency.
This is an estimation for the self-driving hardware cost (computers, LIDAR, sensors). It does not include the base car price, as it can be easily optimized down to almost nothing (sub $10k).
The price is somewhat of a guess, several years ago, the hardware in Waymo was priced at $130k by Munro&Associates. But since then the cost of the LIDAR sensors fell by 90% or so, reducing the main expense.
And Baidu has cars on the road that cost $30k for the _entire_ car. So presumably, so even a couple of pricier sensors won't affect the estimate too much.
> The price is somewhat of a guess, several years ago, the hardware in Waymo was priced at $130k by Munro&Associates
10 years ago they had even more sensors dotting the car, instead of one honeycomb on each corner they had 2, so I find $130k hard to believe given what we know about the sensor kit today.
> But since then the cost of the LIDAR sensors fell by 90% or so, reducing the main expense.
I do not know of any lidar that has done that, and Waymo makes their own and we know their price(-ish) (and quantity). I think they’ve actually gone up in price (but also capability - honeycomb 1 vs gen 2).
Are you talking about raw material costs? Or is that one of these extrapolations of if we scale everything to millions of cars and realise no inefficiencies and nobody making any money in the supply chain?
I'm talking about the current cost of the self-driving system, that is already produced by companies that charge a significant markup. With volume, it will go down more.
I'm not including the base vehicle in the cost. It's highly variable, and can be as low as $10k for small personal intra-city taxis.
Why does it blow away any other public transit? That can't be true because if you put the same self driving tech into a bus, you already am an order of magnitude cheaper per passenger (likely more). Moreover let's assume robotaxis are cornering the market and make all other forms of transport non viable. Why would the public then maintain the roads? So at that point at least costs are suddenly going to explode.
Sigh. People are WAAAY too accepting of urbanist propaganda.
Buses are _barely_ more effective than cars. A regular passenger car with 4 people is more efficient than a city bus. An EV needs 2.5 people (these numbers are for the US).
The explanation is simple:
1. Buses have to drive _all_ _the_ _time_, even when there are few passengers. As a result, the average bus load tends to be around 10-20 people. And you can not increase the bus interval to compensate for it because it makes off-rush-hour bus commutes impractical.
2. Buses have INCREDIBLY polluting components: 2-3 drivers for each bus needed to provide the service. They are by far the dirtiest part of the bus. This part can be removed with the self-driving hardware, but...
A full self-driving bus also makes no sense. It defeats the main advantage of self-driving: door-to-door transportation.
That being said, self-driving mini-buses seating 6-10 people are a good idea for rush hour transit.
> Sigh. People are WAAAY too accepting of urbanist propaganda.
>
> Buses are _barely_ more effective than cars. A regular passenger car with 4 people is more efficient than a city bus. An EV needs 2.5 people (these numbers are for the US).
>
> The explanation is simple:
>
> 1. Buses have to drive _all_ _the_ _time_, even when there are few passengers. As a result, the average bus load tends to be around 10-20 people. And you can not increase the bus interval to compensate for it because it makes off-rush-hour bus commutes impractical.
>
> 2. Buses have INCREDIBLY polluting components: 2-3 drivers for each bus needed to provide the service. They are by far the dirtiest part of the bus. This part can be removed with the self-driving hardware, but...
>
> A full self-driving bus also makes no sense. It defeats the main advantage of self-driving: door-to-door transportation.
Even if you focus only on emissions this completely ignores the cost of congestion, which is huge.
Your complaint about self driving buses makes no sense either. If the most polluting part of the bus is the driver then removing the driver makes the bus far, far less polluting.
When your arguments don't even make sense on their own terms it suggests that you're making them from an emotional position instead of a rational one. That's ok: if you don't like buses just say so, but be honest about it instead of making spurious arguments.
> Even if you focus only on emissions this completely ignores the cost of congestion, which is huge.
Congestion should be fixed by removing buses, de-densifying city cores, and forcing companies to build offices in a distributed fashion.
Meanwhile, replacing buses with shared taxi-style vehicles will do most of the job, while _reducing_ congestion. It's a bit complicated, but it's entirely possible.
The reason is simple, there is an unavoidable tension between the density of bus stops and the average speed. As a result of frequent stops, in most cities buses move at an average speed of less than 20 km/h.
For example, in Seattle it's 15 km/h. This is just 3 times faster than a rapid walk!
If we reduce the number of cars by 2x by adding mild car-pooling during the rush hour, then we'll have more than enough throughput to eliminate congestion _and_ buses in Seattle. This does not generalize to all cities in the US (e.g. Manhattan needs a serious demolishing to become sane) but usually, it's in the same ballpark.
> Your complaint about self driving buses makes no sense either. If the most polluting part of the bus is the driver then removing the driver makes the bus far, far less polluting.
Sure. But why stop there? Buses have an INCREDIBLE impact in the number of lifetimes wasted during commutes.
> When your arguments don't even make sense on their own terms it suggests that you're making them from an emotional position instead of a rational one. That's ok: if you don't like buses just say so, but be honest about it instead of making spurious arguments.
Nope. There are no rational arguments _for_ urbanism. It's a failed obsolete ideology, and it's leading to the downfall of democracty and the rise of populism.
Bus stops are often set too close by municipalities, but that’s driven by the lack of density in US housing. Density drives efficiency.
> Manhattan needs a serious demolishing to become sane
Ah yes, lets demolish one of the most economically productive regions of the USA, both in GDP / capita and GDP / km^2 in order to make it easier for people to drive through it.
> Sigh. People are WAAAY too accepting of urbanist propaganda.
>
Sigh people just like to make statements without evidence to back them up.
> Buses are _barely_ more effective than cars. A regular passenger car with 4 people is more efficient than a city bus. An EV needs 2.5 people (these numbers are for the US).
>
Evidence? Moreover you know that average occupancy rates of cars are around 1.5 [1], for short trips like commuting it's more like 1.1 [1] so that's a factor 2 off from your 2.5. So even if we believe your numbers you have to explain how you're going to increase occupancy rate by a factor of 1.5 to 2 before they become just better (not even blowing out of the water).
[1] https://www.eea.europa.eu/publications/ENVISSUENo12/page029....
Note I could not find numbers on buses, but trains in the above source have occupancy rates of 50%.
> The explanation is simple:
>
> 1. Buses have to drive _all_ _the_ _time_, even when there are few passengers. As a result, the average bus load tends to be around 10-20 people. And you can not increase the bus interval to compensate for it because it makes off-rush-hour bus commutes impractical.
>
And robotaxis have to drive empty to and from the person they are picking up.
> 2. Buses have INCREDIBLY polluting components: 2-3 drivers for each bus needed to provide the service. They are by far the dirtiest part of the bus. This part can be removed with the self-driving hardware, but...
>
Not sure how we should account for bus drivers, considering that even if they are not working as bus driver the person is still around (also should we include the emissions from all the engineers working on self driving tech at the moment then) . However your statement is also false in most western countries, at least green house gas emissions of private households are dominated by transport (i.e. Cars).
> A full self-driving bus also makes no sense. It defeats the main advantage of self-driving: door-to-door transportation.
>
You're contradicting yourself. If the bus driver is the most polluting part of the bus (according to your statement above), then it would definitely make sense to get rid of them.
It would be great if your statement was true and robotaxis are the most efficient thing ever. I'd love to see well laid out evidence for this, but from what I just found your statement is not supported by reality.
The libertarian answer is yes highways should. Most self proclaimed libertarians refuse to go that far - if you allow for highways to not make money then transit shouldn't be held to the higher bar.
Fair, but how unprofitable should they be? -$5/passenger-mike? -$12/passenger-mile? I think we can do a lot better than the current US mass transit status quo.
In 2022, the NYC Subway budgeted about $0.75 per passenger-mile (and that was during Covid, when ridership was very low) [1]. You’re really overestimating how much public transit costs to run. Private vehicles are an extremely inefficient way to move people around, hence the cost of Uber/Lyft/taxis.
> The vehicle is battery-powered, eliminating the need for overhead wires. It features an innovative turning system, enabling it to handle 15m radius curves. This allows for installation in tight corners within the existing highway. The Council intends for it to operate at a high frequency, providing a turn-up-and-go service. The vehicle has a capacity of 56, is comfortable and has low floors to enable passengers to embark and disembark easily. The vehicle has been developed to allow autonomous operation in future.
> The new track is laid just 30cm within the road’s surface, minimising the need to relocate pipes and cables, which is time-consuming and expensive. It achieves this by leveraging cutting-edge materials science, while still utilising standard rail parts to ensure ease of manufacture.
At last they were not trying to use agile!
It feels like that's putting this into a really awkward place in the tradeoff space. Trams work because they can scale higher than buses. That scale comes at the cost of more up-front infrastructure, much less flexibility, and needing dedicated lanes. So cities don't have trams everywhere, but they're only installed on routes that can support the scale.
For these you still have the up-front investment (just less of it) and inflexibility, but don't get the efficiencies of scale due to how small the capacity is.
Is this really just a bet that they can get autonomous tram-driving on city street approved a decade+ sooner than autonomous buses?
The ability for the tracks to be laid so shallow is in my view, the entire innovation and cost is the reason for this approach.
Also, because of the expensive infrastructure that can only be used by trams, there’s a permanence there that prevents future politicians from ripping it out to put more cars on for a quick political win with drivers.
Going back to point 1: having a line means that any route needs to be properly planned because you never have an escape hatch of “just stick them on the road.” Example: where I live, the council installed a bus lane and a cycle lane. Where it pinches in (planning fuck up), it dumps all the traffic into a shared route with 2 roundabouts and 5 exits, each with an insane amount of traffic coming to or from them. Buses that are forced to use that route are always late. It takes me just as long to drive as it does to take the bus, faster if you factor in me waiting for a late bus.
Like many tram lines, CVLR is being laid in-road and not segregated. In fact, while not mentioned here, the it's 15 m turning radius is so important is because it's planned to traverse roundabouts in-lane.
But rather, this is giving up the benefit trams have over buses, without gaining any new edge to replace it. So why is it a good tradeoff? And why now, not 20 years ago?
The autonomous driving angle is the only idea I have.
For comparison, the most frequent London underground service is 100 seconds per train and the system moves about 50k passengers an hour (based on a 21% increase representing 10k passengers, I couldn't find a direct figure), presumably that being both directions.
Even if all that falls through, I'm not gonna complain about it. We sorely need more public infrastructure in the UK. Even if an experiment like this fails, at least you actually get a tram line and experience out of it. Much better than a project which sucks up million then gets cancelled. (Cough cough HS2.)
You can run them at high frequency though.
I definitely agree that the dedicated right of way is the main thing. It's why some of San Francisco's trams are so slow outside of the city centre (where they run in a tunnel) and why Manchester's trams are so slow through the city centre (where they run at surface level sharing the street with pedestrians.)
It’s a worthwhile read BTW
I suspect these are too small to carry a significant number of passengers per hour
They’ll also probably never be autonomous as the challenge with autonomous is less the driving and more with passengers getting on and off, getting trapped etc
Having to hold on to something discards it from my preferred list of solutions.
Battery powered trams have real potential, now that batteries with 5 to 7 minute charging and large numbers of charging cycles are a thing. That's compatible with typical end of line holding times. Steel wheel on steel rail is low friction, and you get most of the energy used to go uphill back when you go downhill. This could work out.
[1] https://youtu.be/XKN0MTCUSV0?t=265
If you were going up and down hills, would you still use steel wheel in steel rail unless you had some sort of cable to work with? I always thought the Muni did relatively level routes for that reason? The Lausanne m2 for example uses rubber (well, ideally you’d be able to just balance the train going up with the train going down, but that only works for simple inclines with limited stops). Actually, a battery powered rubber wheeled tram service on some sort of steep incline like SF’s cable car routes could get some wicked regen going down.
Even if level, they could still get some regen from making stops.
Revolutionary as the turning circle will be used at speed with passengers to traverse roundabouts in-lane. CVLR doesn't need turning loops, as the vehicles can be driven from either end.
I haven’t found the projected figures for Coventry but it would be very, very awkward if they can’t beat the numbers above with a supposedly much cheaper track.
https://en.wikipedia.org/wiki/Trams_in_Besan%C3%A7on?wprov=s...
Still, there's no point comparing build costs between France and the UK as they're completely different cultures and jurisdictions. Instead, a more reasonable approach is to compare to recent similar project in the UK.
Edinburgh's tram covers 18.5 km and cost at least (they're still uncovering overruns years later) £1 BN. That's ~£50 MM or ~€60 MM per km. That's what CVLR should and will be benchmarked against.
VLRT seems gimmicky at first but the more I look at it the more sense it makes.
The answer is of course that rails provide major advantages on their own, primarily by allowing vehicles to travel much more efficiently thanks to the low friction of running steel wheels on steel tracks
“Thanks to the very low friction between the steel wheel and steel rail, railways can move a load using as little as 15% of the energy that road haulage needs.”
Gareth Dennis, How Railways will Fix the Future (https://www.penguinrandomhouse.com/books/761930/how-the-rail...)
They make all kinds of claims that don't stand up to over 100 years of history running trains. The claim they are innovative, but there is nothing new here, and no evidence they have looked at the real problems of transit systems. Someone is going to make a lot of money on this at the expense of the community that loses.
Trains have been around for a long time. You can buy all the parts you need for a good system off the shelf. You won't be saving money by designing something new, you just waste money on engineers to design something and then lose the scale factors you could get from buying the same thing as everyone else. If you buy the same thing as everyone else that means there will be a market for spare parts and thus in 20 years when (not if!) something breaks you can keep the system running.
Yes overhead wires are expensive - but they are a rounding error compared to track. Batteries are expensive too, and you have to buy a lot of them. Batteries need to be recharged which means these trams will be out of service often so they have to buy a lot more so that when one is out of service for charging the others can work. (you still need a few extra for maintenance, but battery charging is more common so you need a lot more)
If you want to build a train the best way to save money is to build exactly the same as everyone else does: standard off the shelf trains, running on standard off the shelf rails, and standard off the shelf overhead rail. If you want to innovate make sure that everyone is fluent in Spanish, Turkish, Korean, or Italian - because places where those languages are spoke build and run trains much cheaper than other places you can think of so you want to learn from them. (note that French or Japanese are not on the above list - while those areas do cheaper than English speakers, they are still expensive)
I'm not sure about the UK, but in the US most of the cost blowout for trains seems to be in stations, so focus all your innovation there: don't make them monuments to how much money you can spend. (The UK has cost problems almost as bad as the US, but I'm not aware of any study on where the issues come from, while at least in the US there are studies).
Anyway everyone is pretty sure that that something is wrong with the standard train economics as you describe them, because if there wasn't something wrong with it there'd be a lot more trains. I can't tell from the site, or from your comment, if this is the solution, or even worth doing as an experiment... but "don't change anything ever" doesn't strike me as productive either.
Innovation should require some knowlegde of what is already done - otherwise you invent square wheels.
Adding a bus line isn't sexy, even bus rapid transit (BRT) sounds like a wet fart. They work, they can work extremely well, but nobody gets excited about it.
This thing is just like a monorail; something worse than a bus but that sounds sexier.
I agree with much of your sentiment, and hope that the Coventry council is being challenged in these sorts of ways, but at the same time I recognise that each city is going to have quite different requirements for trams driving down the roads in its centre.
Perhaps a better push back is: why isn’t this just a better bus network?
There are different modes of operation that differentiate them but fundamentaly they are all trains and face the same issues
Again I sorta see what you mean, but feel you’re massively over simplifying this.
Ceci n'est pas une tram: https://www.youtube.com/shorts/kMUANU9H6aw
https://en.wikipedia.org/wiki/Rubber-tyred_metro and https://en.wikipedia.org/wiki/Guided_bus also exist.
(For me, the big thing about trams and trains and subways, etc is that the track is a kind of social construct - the track tells me that eventually a vehicle will come for me - no need to really worry about timetables, etc. A bus, a bus may come, maybe it won't. It's all psychoillogical but it's there the same.)
The second sentence is partially true: they do have different modes of operation.
But no, they don’t face entirely the same issues. Trains should hopefully never routinely encounter cars sharing their track and they don’t have to make tight turns to follow existing roadways.
In Australia, highest cost is buying up required land and construction of buildings. We spent ~100mil USD on a single, open air platform for a line extension of exactly that one station. It was about 5 km of extra track. It is amazing we have any trains at all.
Eliminating overhead wires isn’t about cost. It’s about being able to build in existing urban areas that don’t want high voltage live wires everywhere, and likely already have above ground infrastructure they would interfere with.
There’s nothing stopping a road from being smooth but, logistically, there’s clearly no reason to rush to repair roads when they deteriorate. That means potholes get tolerated, potholes means suspension, and both of those mean bus-like rides instead of suburban light rail rides.
Railway track has to be flat. Anything less than perfect is intolerable so it tends to hold its maintainers to a higher bar.
I've found the new battery buses to be far more comfortable to ride in than older diesel buses since they remove the vibration when idling. The extra weight might mean more potholes to repair though.
And lastly badly maintained railway lines are just as prone to causing motion sickness as badly maintained roads.
The fact that buses are so flexible and easily (and cheaply) rerouted makes developers less likely to build developments that rely on access to transit, but once a community spends a hundreds of millions of dollars on a light rail line, they know it's there for the long term.
https://www.washingtonpost.com/dc-md-va/2025/05/27/steetcar-...
Jarrett Walker has a good piece about it: https://humantransit.org/2025/05/what-was-wrong-with-the-was...
I agree with him that in order to endure and justify a permanent operating subsidy a transit service needs to be useful and used by many people. Most American light rail doesn't meet that bar.
I think there is another aspect that usually goes unstated, which is the vibes. If you're a mayor you want to build a tram. If you're a tourist you want to ride a tram. If you're a prospective resident you want to live near a tram. Yes, it's smoother and yadda yadda, but really it's because it has more sex appeal. A technically equivalent bus may well be _technically_ equivalent but could never be truly equivalent. Nobody would write a play entitled A Technically Equivalent Bus Named Desire. In a way, spending money on a tram is similar to spending money on parks or flowers or public art. And so we will spend the money; and we will build the streetcar; and damn the technical equivalence.
I wonder what the world would be like if we were honest with ourselves.
Modern urban light rail is also typically electric, using overhead power. Although buses can also use this.
This is one of the main reasons the super dense Japanese cities aren't as air poluted as other urban centers.
Bus rapid transit, when done right (basically, almost like a tram) can be quite successful: https://www.youtube.com/watch?v=fh1IaVmu3Y8
Since it's harder to make that choice when you're building rail, it's more likely to be done right.
Not really that efficient...
And, as has been rediscovered about 200 times in Southern California (by the drivers, not by the sstate government), you can add additional lanes almost indefinitely, and it doesn't really help congestion that much.
Busses aren't much more efficient when riding down a lane than lower occupancy vehicles, but streets aren't bottlenecked by their roads, they're bottlenecked by their intersections. The key advantage of a bus is at the intersection. A bus holds the intersection for far less time than the equivalent passenger capacity of cars.
The problem bus lanes try to solve is dominantly that without them the traffic advantage of people riding busses mostly goes to people not riding busses, and this makes for a pretty terrible incentive structure. Busses are intrinsically disadvantaged against cars (schedules, uncertainty, routes), so if you don't help them, then people will prefer to drive. Bus lanes internalize the externality.
And your bus only lane has a lot more options. If there is a major disaster you can divert other traffic (not necessarily all traffic though that is an option) into it which might be a useful compromise at time. If you need to repair your bus only lane you just divert the bus to regular traffic. For that matter most places there isn't any traffic and so a bus in mixed traffic has no downsides thus not costing you that whole lane (or track), just build the bus-only lane where it is needed.
Trains are a good thing when they do something a road cannot. However the common bus can be just as good for much less. If you have the money and want good service and ride quality the bus can do it too, and typically for much less cost than a train.
Trains are good where they don't mix with traffic (meaning elevated or underground) because they can then be automated (and also faster). Alternatively a train can hold more people, so if you are in the rare situation where a 100 passenger bus every 5 minutes can't handle the passengers a train is good. Most of the time though you are not in either situation and so a bus can do everything a train can.
Unless the track is just in a regular lane that can be full of cars/busses/trucks whenever there isn’t a light train. Like how trams work in most of the world
While that bus lane may look empty most of the time it likely carries far more people per hour than the congested car lane next to it.
> While the Lincoln Tunnel’s car lane can only move 3,000 people per hour in each car lane, its bus lane moves 30,000 people per hour.
https://transalt.org/blog/bus-commutes-are-significantly-lon...
> Now the XBL handles 1,850 buses that carry more than 70,000 passengers from 6 a.m. to 10 a.m. each weekday, which comes to 600 buses an hour. The bus lane operates at its maximum capacity for 90 minutes of its four-hour operation.
https://www.govtech.com/transportation/fed-funds-study-of-ai...
Here in San Francisco along Mission St we have about 20 articulated buses an hour in each direction. These have a planning capacity of 94, 85% load standard 80, 125% crush capacity 119 according to https://www.reddit.com/r/AskSF/comments/445xdg/what_is_the_m....
While mostly a bus and taxi lane Mission St allows local traffic within each block so buses are still a minority of the vehicles in the lane.
Meanwhile the main 2 lanes in each direction street nearby has 1020 vehicles an hour in the peak direction. At 1.6 people per vehicle that's only about 830 people per lane at rush hour. So even at 'standard capacity' the buses in a regular city street not completely dedicated bus lane carry double the number of people. (From experience I suspect it is somewhat more than that.)
That's a bus every 5.1 seconds. In a single lane. (and at 30mph it'll take 1.5 of that 5 seconds just for the bus itself to pass. That's very marginal braking distance).
Also, 1850 / 4 is 453, not 600.
The article I quoted to which you are replying suggests 600 busses an hour. I don't think that is unreasonable for a dedicated highway lane into a bus terminal. There's a nice picture of it here: https://abc7ny.com/port-authority-lincoln-tunnel-technology-...
> Also, 1850 / 4 is 453, not 600.
Quoted in the post you are replying to:
> Now the XBL handles 1,850 buses that carry more than 70,000 passengers from 6 a.m. to 10 a.m. each weekday, which comes to 600 buses an hour. The bus lane operates at its maximum capacity for 90 minutes of its four-hour operation.
I read that as they reach the maximum capacity of 600 buses an hour only for the 90 minutes of rush hour. Across the 4 hours it operates each bus averages 38 passengers (70000/1850). It seems reasonable to assume that the rush hour buses are more packed given they are looking at ways to increase capacity and have you ever taken a rush hour bus in a big city?!
From the picture linked above these seem to be 53 seat coaches for longer distance routes rather than city buses which would carry more passengers with some standing. 50 * 600 = 30,000. It's in the ballpark!
A rail track for the same route sits empty just as much.
> you can add additional lanes almost indefinitely, and it doesn't really help congestion that much.
I don't think adding bus-only lanes would have that effect. Adding lanes for private vehicles reduces congestion, which encourages people to move to places along the route until the congestion reaches the previous barely-tolerable level (as I understand it).
Other advantages: people who don't drive, which includes children can get about. Lots of public transport can compensate alot for un walkability of suburbia.
You can make the same argument (in terms of space) about a train track. The real advantage of trains (light or heavy) is permanence. It's easy for the next government to remove the bus lanes because "OMG too much traffic, one more lane will fix it." It's much more difficult to rip out a rail line and convert it to a road.
Getting 1000 people downtown could be up to 2,000 Waymo trips (one trip to drop off the worker, another trip for the car to go back out to pick up another passenger). While one of these 56 passenger very light rail cars can do it in 18 trips. A light rail vehicle like the Siemens trains used in San Francisco can carry up to 200 people at crush loads, so that's 5 trips.
* Think having much higher speed limits (as far as humans are concerned, nonexistent), or mass coordinating movement over the entire traffic.
** We can reasonably estimate the minimum without bothering to ask how fast the tech will improve: Even if the tech were available now, think about fleet replacement costs which no one group would be too eager to pay. Best case, it's the typical 'make a concentrated pressure group lose for societal benefit' and we know how that politics goes. It will happen, but slowly.
*** Another thing to account for is that there's no good reason to design an AV car like a normal car, and there'll be some iteration time over that too.
I don’t think fixed route transport infrastructure is going to have trouble competing on efficiency.
They were targeting $7.5k for their in house honeycomb lidars and they have 12 of them - that’s 90k already.
https://www.theverge.com/2021/8/27/22644370/waymo-lidar-stop...
They also aren’t close to the $7.5k target (there isn’t any public source for that so you’ll have to take my word for it).
Also $30k wouldn’t even cover the base vehicle.
The price is somewhat of a guess, several years ago, the hardware in Waymo was priced at $130k by Munro&Associates. But since then the cost of the LIDAR sensors fell by 90% or so, reducing the main expense.
And Baidu has cars on the road that cost $30k for the _entire_ car. So presumably, so even a couple of pricier sensors won't affect the estimate too much.
> The price is somewhat of a guess, several years ago, the hardware in Waymo was priced at $130k by Munro&Associates
10 years ago they had even more sensors dotting the car, instead of one honeycomb on each corner they had 2, so I find $130k hard to believe given what we know about the sensor kit today.
> But since then the cost of the LIDAR sensors fell by 90% or so, reducing the main expense.
I do not know of any lidar that has done that, and Waymo makes their own and we know their price(-ish) (and quantity). I think they’ve actually gone up in price (but also capability - honeycomb 1 vs gen 2).
Waymo uses brand-new electric Jaguars.
But there is no _reason_ to use Jaguars and not specially-built smaller and less powerful cars, when Waymo finally starts a real rollout.
I'm not including the base vehicle in the cost. It's highly variable, and can be as low as $10k for small personal intra-city taxis.
China has already launched a $30k taxi: https://www.forbes.com/sites/bradtempleton/2024/05/14/baidu-...
This _completely_ blows any transit out of the competition. Literally nothing can come even close in the end-to-end efficiency.
Buses are _barely_ more effective than cars. A regular passenger car with 4 people is more efficient than a city bus. An EV needs 2.5 people (these numbers are for the US).
The explanation is simple:
1. Buses have to drive _all_ _the_ _time_, even when there are few passengers. As a result, the average bus load tends to be around 10-20 people. And you can not increase the bus interval to compensate for it because it makes off-rush-hour bus commutes impractical.
2. Buses have INCREDIBLY polluting components: 2-3 drivers for each bus needed to provide the service. They are by far the dirtiest part of the bus. This part can be removed with the self-driving hardware, but...
A full self-driving bus also makes no sense. It defeats the main advantage of self-driving: door-to-door transportation.
That being said, self-driving mini-buses seating 6-10 people are a good idea for rush hour transit.
Even if you focus only on emissions this completely ignores the cost of congestion, which is huge.
Your complaint about self driving buses makes no sense either. If the most polluting part of the bus is the driver then removing the driver makes the bus far, far less polluting.
When your arguments don't even make sense on their own terms it suggests that you're making them from an emotional position instead of a rational one. That's ok: if you don't like buses just say so, but be honest about it instead of making spurious arguments.
Congestion should be fixed by removing buses, de-densifying city cores, and forcing companies to build offices in a distributed fashion.
Meanwhile, replacing buses with shared taxi-style vehicles will do most of the job, while _reducing_ congestion. It's a bit complicated, but it's entirely possible.
The reason is simple, there is an unavoidable tension between the density of bus stops and the average speed. As a result of frequent stops, in most cities buses move at an average speed of less than 20 km/h.
For example, in Seattle it's 15 km/h. This is just 3 times faster than a rapid walk!
If we reduce the number of cars by 2x by adding mild car-pooling during the rush hour, then we'll have more than enough throughput to eliminate congestion _and_ buses in Seattle. This does not generalize to all cities in the US (e.g. Manhattan needs a serious demolishing to become sane) but usually, it's in the same ballpark.
> Your complaint about self driving buses makes no sense either. If the most polluting part of the bus is the driver then removing the driver makes the bus far, far less polluting.
Sure. But why stop there? Buses have an INCREDIBLE impact in the number of lifetimes wasted during commutes.
> When your arguments don't even make sense on their own terms it suggests that you're making them from an emotional position instead of a rational one. That's ok: if you don't like buses just say so, but be honest about it instead of making spurious arguments.
Nope. There are no rational arguments _for_ urbanism. It's a failed obsolete ideology, and it's leading to the downfall of democracty and the rise of populism.
> Manhattan needs a serious demolishing to become sane
Ah yes, lets demolish one of the most economically productive regions of the USA, both in GDP / capita and GDP / km^2 in order to make it easier for people to drive through it.
Listen to yourself, this is deranged.
How common are those? I always see them with just one person on board.
Sigh people just like to make statements without evidence to back them up.
> Buses are _barely_ more effective than cars. A regular passenger car with 4 people is more efficient than a city bus. An EV needs 2.5 people (these numbers are for the US). >
Evidence? Moreover you know that average occupancy rates of cars are around 1.5 [1], for short trips like commuting it's more like 1.1 [1] so that's a factor 2 off from your 2.5. So even if we believe your numbers you have to explain how you're going to increase occupancy rate by a factor of 1.5 to 2 before they become just better (not even blowing out of the water). [1] https://www.eea.europa.eu/publications/ENVISSUENo12/page029....
Note I could not find numbers on buses, but trains in the above source have occupancy rates of 50%.
> The explanation is simple: > > 1. Buses have to drive _all_ _the_ _time_, even when there are few passengers. As a result, the average bus load tends to be around 10-20 people. And you can not increase the bus interval to compensate for it because it makes off-rush-hour bus commutes impractical. >
And robotaxis have to drive empty to and from the person they are picking up.
> 2. Buses have INCREDIBLY polluting components: 2-3 drivers for each bus needed to provide the service. They are by far the dirtiest part of the bus. This part can be removed with the self-driving hardware, but... >
Not sure how we should account for bus drivers, considering that even if they are not working as bus driver the person is still around (also should we include the emissions from all the engineers working on self driving tech at the moment then) . However your statement is also false in most western countries, at least green house gas emissions of private households are dominated by transport (i.e. Cars).
> A full self-driving bus also makes no sense. It defeats the main advantage of self-driving: door-to-door transportation. >
You're contradicting yourself. If the bus driver is the most polluting part of the bus (according to your statement above), then it would definitely make sense to get rid of them.
It would be great if your statement was true and robotaxis are the most efficient thing ever. I'd love to see well laid out evidence for this, but from what I just found your statement is not supported by reality.
[1]: https://data.transportation.gov/Public-Transit/2022-2023-NTD...