Even with single people in cars you can move wayyyy more than 100 people per hour in the top left.
Assume 25 mph speed and 30 feet between cars, each car crosses 30 feet in about a second. 3600 seconds in an hour, times 2 for both directions and you have 7200 people that can move on that little road.
Now add additional passengers…buses…it can move a decent amount more. There’s lots of reasons cars suck but let’s not make up math to prove the point.
It’s not saying that the top row can support at most 100 people.
Just that if you have 100 people per hour, you need something like what’s in the picture. The train tracks aren’t being fully utilized in the top pic, either.
As an aside, you’re forgetting that cars are ~15 feet long on average. So you’ve got an hour of traffic with consistently 1 car following distance, which is fairly unrealistic. Real world capacy of a lane is closer to 2k people per hour, or 4k both directions.
Yeah and the big road below can hold WAY more than 10,000 too. The numbers here are all made up and it doesn’t really do a good job of making the point the creator wants to make.
Yeah.
I think I count 23 lanes in the bottom pic.
Ignoring the effect of heavy vehicles and assuming a free flow speed of 70, the federal highway authority’s numbers would be 2400 vehicles per lane or 55k vehicles per hour. Assuming an average occupancy of 1.5 people per vehicle, that’s nearly 83k.
I’m having trouble finding actual sources right now for max rail capacity, but https://en.m.wikipedia.org/wiki/Passengers_per_hour_per_direction claims 60-90k passengers per direction on 3.5 meter lanes for “suburban rail”.
Although 83k people per hour is 41.5k people per rail track. Assuming a 360 person train like the Bombardier BiLevel Coach, that’s only 115 train cars per hour per track. If each train has 11 cars, that’s 10 trains per hour or a train every 6 min. Not really that unreasonable, and the tracks will look mostly empty unlike that monstrosity of a road.
At 25mph, the safe distance between cars is closer to 60-70 feet. Add the length of the cars for another 15-20 feet and your throughput calculations drop by a factor of 2.5-3 already.
It gets worse once you start considering comparable velocities. Trains go way over 25mph.
Also assume that no one is turning onto or off of the road?
Theoretically the highway I can see outside my window could handle tens of thousands of passengers per hour moving at over 60mph. But for some odd reason when I look out my window on workday it’s moving significantly less than 25 mph. Some days is not even moving at all.
Yeah but for long term growth is not ideal, the tracks will do a better job in long run.
No matter the math, trains move more people, faster and safely. What you should use for your argument is that it’s easier and better to low capacity roads in rural areas (low population) than building trains to replace the car everywhere. Either way there is no argument against trains from city to city or a metro. Cars get out competed there.
Quick search gave this number:
Theoretical maximum saturation flow rate per lane (this will allow you to do quick calculations in your head to check reasonableness at big events): 1,900 vehicles per hour per lane
So the bottom would probably be more like 25K each way. Lightrail is only about 4-8k? Meanwhile a single subway lane each way could do more than that thing on the bottom left.
I’m guessing you found this source: https://www.mikeontraffic.com/numbers-every-traffic-engineer-should-know/
The number from that page he should actually be using is more like this one:
Planning level daily capacity of a road (Round numbers based on Level of Service D/E thresholds in HCM 6th Edition)
- 2 lane (w/ left turn lanes): 18,300 vehicles per day
(Source: I’m a former traffic engineer.)
I really wish I could use those roads for transport using a bicycle. I just don’t feel like being passed by a truck moving at 80km/h just a few centimeters away in a curve with bad visibility, potentially even with fog in the morning.
You can make multiple extra lanes for cars, but not a single lane for bicycles?
TBH, where I live, those 80km/h roads aren’t as bad as you would think. Cars slow down before bends because they anticipate that a bicycle, hiker, tractor or whatever slow moving vehicle and usually pass them with decent space.
But that is only true for less frequented roads, if there is heavy oncoming traffic and save overtaking is not possible, people will still try to squeeze through and there separated bike lanes are really important.
You’re making the right point, BUT pretty much every train service provider would add more parallel tracks if they increase the number of trains to a certain point, because they start getting in the way of each other
As always, the problem with commuter trains is the last mile. If you work in the city, there is probably some form of bus or subway, but if you work in an unwalkable suburb, you’ll need an Uber for that last mile which cuts into the benefit.
that’s not a problem with trains it’s a problem with unsustainable land use
@themeatbridge @sexy_peach Commuter driving has the same ‘last mile’ problem, but it’s parking.
The photo doesn’t include the $250 million worth of carparks for those 10,000 cars that has to exist at the other end of the highway.
I agree with you, but employers are solving that problem by leaving densely developed places for suburban and rural locations. This contributes to sprawl and compounds the complexity of the problem. All because public transit can’t solve the last mile problem.
We need adaptive infrastructure and regulated development to coincide with public transit, but at least in the USA, I might as well be talking about flying to Mars on unicorn farts.
Regulatory capture isn’t just a thing that happens, it’s the very foundation of our political system. Like a house grown from fungus, it’s not “corrupted” because the corruption is all there is.
The problem is the unwalkable suburb that doesn’t make any sense. It never made sense either.
It’s not only bad for commuting. It’s a mess for groundwater, pollution of all type (noise, microplastics, air, etc.) It has an impact on the wildlife including reproduction, on plants, etc.
It’s just a bad use of space? No, it’s bad socially by isolating people. It creates urban traps. I will stop here otherwise I will continue on the fact it’s a myth created by the capital…
surely you can bike 2 miles in the burbs? One of the upsides of suburbs being so painfully sprawly is that barely anyone lives there, so you shouldn’t have a tremendous amount of traffic on those 2 miles to the train station.
And even if you’d fear for your life biking there now, it’s not like you need to build bike paths along every little residential street to fix it, start with the largest most high-traffic roads and build your way down until people feel safe biking to the train station.
Sure, but then you have to carry your bike with you on the train. There is no workable solution to suburbia that doesn’t involve cars because it was designed and built around them. Unfortunately, they’re now home to tens of millions of people, and any quick solution would most likely end up hurting a lot of them.
Bike parking at the train stations. You bike to the train station, lock the bike up, take the train, take the second bike from the destination train station, bike to the office. See videos on how the Dutch do it. Even with multiple bikes it’s incredibly cheap in terms of money as well as climate impact compared to even the cheapest cars.
Actually, you can leave a bike at the bike garage near the station or rent one on a monthly basis. That’s what they do in Japan.
Well, in the Netherlands and at least some other EU countries most train stations have a bike rental system that works by just using a card to unlock the bike for a couple of Euros for 24 hours. So there is a possible solution.
Many people here use that system. It’s also possible to buy a (second-hand) bike and park it at the station where you need it, if you’d like.
Edit: Didn’t see the post below… but exactly that.
My nearest bus stop is four miles away and I would definitely die if I tried to ride a bike there. These roads are crazy dangerous.
The whole point of this sub is advocating for changing that and getting rid of car centric development.
I think, eventually, this is where autonomous vehicles will really come into their own.
You are absolutely right that first mile/last mile is a barrier for rail travel - but imagine if we could design the station around a fleet of AV’s.
Imagine:
Your AV takes you to the station, and parks right next the platform at the exact location along the train for your seat reservation.
You wait in your nice climate controlled AV for the train to arrive - hope out and onto the train.
Meanwhile somebody else gets off the train and uses the AV you’ve just vacated to complete their journey.
These things all complement each other. Busses are great in urban areas, but they don’t work well in rural areas, they just don’t compare well vs private car when you look at generalized journey times (GJT).
but why on god’s green earth would you spend the money on autotaxis rather than buses and/or bike infrastructure?
All these things should work on harmony. In some situations busses and bikes don’t work as well. Let’s say you are going on holiday with luggage.
The end game is to reduce the the reliance on personal cars. Right now most people feel they need their own car. Much of this is down to first mile / last mile arguments.
Long headways, and high friction interchanges are things AVs could potentially help to eliminate one day. I would actively encourage consideration of multiple pickup and drop off by those AVs - key is we probably want to get people to their doors and we need high frequencies, or ad-hoc departure times to complete with car.
Yes, exactly, this would solve the last mile problem and solve the AV problem with long-distance trips. To get there, though, you might need to make certain areas exclusively accessible via autonomous vehicles. For instance, make certain cities AV only, and free up some road space for walking and biking.
But I recognize that this is about as likely as getting everyone to stop turning green space into parking lots.
Remember when Robert Moses intentionally made the parkways hostile to buses and trains? There’s a bit in The Power Broker about how his engineers wanted to put trains in, or at least build the roads so it would be easy to do later. Moses said no.