6 ms·

I can’t speak to the aggregate, but going from two to three lanes in each direction on I-90 in northern IL has cut travel times for us by about 8% despite incre

I can’t speak to the aggregate, but going from two to three lanes in each direction on I-90 in northern IL has cut travel times for us by about 8% despite increased total traffic. This is because trucks passing now leave the left lane open and because the speed limit was increased 5MPH.

rplst8 8y ago
Yeah, I think that saying more lanes means more traffic is just ignoring the fact that the current road system never met the original demand. Also, we obviously have to plan for growth. We do have more people on the roads than we did in decades past. I haven't checked the numbers but I bet highway-lane-miles has not kept pace with population growth.
- sliken 8y ago
  Well say you have a particularly busy 10 mile section of highway. You spend $millions adding lanes. Commuters are no happier because their commute time is unchanged. Riding on public transit drops which is worse for the environment. Was adding the lanes a win for the city? The commuters? The environment? It is counter intuitive, but if you think about it. Everyone has a commuting pain threshold that will cause a change in behavior. If a stretch of highway takes 10 minutes less because of additional lanes, then people will start commuting from 10 minutes further away. Fortunately it's really easy to exactly quantify trip times, cars per lane, and similar. Quite a few studies have shown short term benefit, but within a year the traffic is within 0.1% of what it started with before adding the lanes.
  - Rescis 8y ago
    > Was adding the lanes a win for the city? The commuters? The environment? It was a win for the local economy. By allowing more people to drive to and from locations they please, you are allowing more people to work jobs they otherwise wouldn't be able to, and purchase goods and services they wouldn't otherwise. I'm rarely a fan of government spending; but, roads, police, and firefighting are probably some of the least evil.
    - lhopki01 8y ago
      Why not public transport? Over the long term it's cheaper.
      - AlgorithmicTime 8y ago
        It's pretty inflexible. Public transit generally feeds into a hub from the outlying areas. If you need to go from one of the spokes to another, it will generally be incredibly inconvenient to make the trip via public transit. I don't see increased funding really fixing that.
    - CalRobert 8y ago
      Giving people an all-you-can-eat buffet of asphalt encourages extremely inefficient resource allocation. Doing this without asking for anything to offset the negative externalities exacerbates the problem. So far the negatives of increased vmt have been completely ignored - they are not minor. Ask yourself - would you enjoy living on a busy street, or a quiet one? A wide one, or a narrow one? Which would you rather see your kid walk or cycle to school on? Which will have cleaner air? More noise? Would you rather your 85 year old parents or grandparents had to walk across an 8 lane road or a 2 lane one to get to the post office from their home?
      - freehunter 8y ago
        You're comparing streets with roads, here. Fundamentally I agree with you, big roads divide communities and make cities unwalkable. But they are necessary. A street is made for transporting humans first and foremost. It has sidewalks, driveways to houses are accessed directly from the street, and pedestrians can cross with relative ease, to the point that crosswalks are basically unnecessary. A road is made for transporting cars first and foremost. There shouldn't be many residential driveways directly leading into a road, there may be sidewalks but they're not going to get used often, and you should rarely see pedestrians trying to cross. Crosswalks are very necessary on roads. There's no getting around the fact that we need roads. Cars and trucks need ways to move long distanced quickly. The problem becomes when city designers try to mix streets and roads (to make a stroad), leading to massive arteries running through the heart of a residential neighborhood. Proper city design puts roads outside of pedestrian-heavy neighborhoods and fills them with easily and safely walkable streets instead. There's nothing wrong with an 8 lane road, as long as that road isn't supposed to be used as a street as well. https://www.strongtowns.org/journal/2018/3/1/whats-a-stroad-and-why-does-it-matter https://www.strongtowns.org/journal/2018/3/1/whats-a-stroad-...
- dawnerd 8y ago
  A lot of people here in Portland don't seem to grasp that. They go, well adding an extra lane will just make that lane full... yeah... exactly otherwise whats the point of building another lane? Mass transit is a great idea in theory, but when it doesn't run 24/7 to areas you want to go or has a problem with homeless and other crazy people harassing you [1, 2, 3, 4] it just doesn't work out. A good solution for a lot of places with tight space is to just stack the highways. Doesn't make sense endlessly making roads wider on both sides - it can only go so far. 1. https://www.kgw.com/article/news/crime/trimet-barber-gets-2-years-for-cutting-womens-hair-in-public/283-454639803 https://www.kgw.com/article/news/crime/trimet-barber-gets-2-... 2. https://www.oregonlive.com/portland/index.ssf/2017/05/police_responding_to_ne_portla.html https://www.oregonlive.com/portland/index.ssf/2017/05/police... 3. http://www.wweek.com/news/2017/06/02/man-pummels-max-train-operator-while-screaming-about-first-amendment-rights/ http://www.wweek.com/news/2017/06/02/man-pummels-max-train-o... 4. https://www.oregonlive.com/portland/index.ssf/2018/05/crime_increases_as_trimet_weig.html https://www.oregonlive.com/portland/index.ssf/2018/05/crime_...
  - Thlom 8y ago
    WTF. Mass transit is a great idea period. It works in numerous places around the world. Even if it doesn't run 24/7 or everywhere it runs most of the day and to many places. Meaning less cars and less need to "stack the highways"(!!!), meaning less space used for parking and roads and more space available for humans.
    - rplst8 8y ago
      It doesn't work for outlying areas. The further you get form a hub, the more varied the travel plans are. Express services work for connecting hubs. But it's the 30-60 mile out suburbs that are a challenge. Note, they are only a challenge if bureaucrats and big business continue to pour money into centralizing resources in giant cities. In a modern Internet connected economy, there is very little reason to colocate so many government services and large corporations.
  - Broken_Hippo 8y ago
    Mass transit isn't perfect, so it shouldn't be had? That seems like flimsy logic when a number of the issues can be fixed. Move to smaller over-the-road mass transit for off-hours or have fewer busses. You don't need to have full-size busses at 2am when you can use the smaller busses that schools use at times, for example, or simply have a bus that runs once an hour. You can make sure that major employers are serviced by busses either regularly or at times when their shifts start and stop (factories, for example). You can use van-sized taxis for smaller areas and adjust the routes to meet needs in smaller areas or have electric, automatic trams that run at specific times through the day and less so at night. Intercity travel can be more restricted if the demand isn't there. Amsterdam has folks scan their ticket for the trams on their way out ... so they can see where folks are going to and from, in general, to better meet demand. Something like this can surely be done in different ways. Even more, you can create safe walking and cycling paths so folks are more likely to be able safely get to public transport. Have bus shelters many places. Perhaps don't expect it to make a profit. Perhaps tax vehicles to help pay for them when they are available to the user - after all, if you own a car when public transport will adequately fit your needs, the car is a luxury. Perhaps utilize more tolls to help pay for them. I've never had someone harass me on a bus where I am at now. In fact, I didn't have this issue in the states either when I was lucky enough to live in a place with busses. It would seem the solution would be to actually take care of folks that are homeless and mentally ill. It would make sense to call the police if someone is causing an actual disturbance to others. These aren't problems with public transportation, these are problems with society.
baddox 8y ago
How long ago were the lanes expanded? According to the general concept of latent demand, I would expect it to take perhaps a few years for the latent demand to manifest.
- 1123581321 8y ago
  About two years. I agree it should continue to increase over the next several years as homes and businesses are located with the wider highway in mind. However, if latent demand takes too long to manifest, the lane expansion has saved driving time for a significant fraction of its life and shouldn’t be thought of as ineffective.
  - TheCoelacanth 8y ago
    Adding a lane to an urban highway is immense. There is not only the cost of building the actual road, but the cost of acquiring the land which often requires displacing people from their homes via eminent domain and the cost of the disruption caused by the construction. Just providing some benefit is not enough to justify the cost; it must provide an enormous benefit.
repsilat 8y ago
Also: induced demand is a good thing. Even if travel time were the same with three lanes instead of two, that's 50% more people moving down that road. That's a quantifiable social benefit.
- joe_the_user 8y ago
  Even if travel time were the same with three lanes instead of two, that's 50% more people moving down that road. That's a quantifiable social benefit. Well, maybe those 50% achieve some benefit to themselves and society once they arrive at their destination. Keep in mind, if those people happen to be arriving at jobs they had previously, that's not a greater benefit than before. However, the movement of people down the road itself is a social detriment. Most people don't to spend time in traffic for kicks and the cost of fuel consumption, pollution, wear on highways and wear on cars is significant. I mean, if somehow I could spend only five minutes in my car per day and still get to my destinations, the benefit would clearly be far greater.
- sjwright 8y ago
  > That's a quantifiable social benefit. Only if you know how the occupants in these additional vehicles were transiting previously. If they were previously carpooling, or if they moved away from a good (but slightly less time efficient) public transport option, then the social benefit would be somewhere between minimal and nil.
  - chii 8y ago
    But presumably the new occupants compared their existing old travel method, and deemed the new one better. If the old method had some "social benefits", it must mean that the old method's social benefit came at a cost in benefit to the occupants. Otherwise, they would not have chosen the new method!
    - JumpCrisscross 8y ago
      > the new occupants compared their existing old travel method, and deemed the new one better You’re leaving out the taxpayers subsidising their commute.
gascan 8y ago
There definitely seems to be a couple of functionally optimal road sizes, where extra pavement dramatically improves flow and by doing so at least appears to greatly improve throughput. In our town, the city has been switching from tight two lanes each way to one lane each way, plus turning lanes and bike lanes, and these new layouts are significantly more pleasant to drive with none of the old left-turn snarls of the past.

rplst8 8y ago

Yeah, I think that saying more lanes means more traffic is just ignoring the fact that the current road system never met the original demand. Also, we obviously have to plan for growth. We do have more people on the roads than we did in decades past. I haven't checked the numbers but I bet highway-lane-miles has not kept pace with population growth.

sliken 8y ago
Well say you have a particularly busy 10 mile section of highway. You spend $millions adding lanes. Commuters are no happier because their commute time is unchanged. Riding on public transit drops which is worse for the environment. Was adding the lanes a win for the city? The commuters? The environment? It is counter intuitive, but if you think about it. Everyone has a commuting pain threshold that will cause a change in behavior. If a stretch of highway takes 10 minutes less because of additional lanes, then people will start commuting from 10 minutes further away. Fortunately it's really easy to exactly quantify trip times, cars per lane, and similar. Quite a few studies have shown short term benefit, but within a year the traffic is within 0.1% of what it started with before adding the lanes.
- Rescis 8y ago
  > Was adding the lanes a win for the city? The commuters? The environment? It was a win for the local economy. By allowing more people to drive to and from locations they please, you are allowing more people to work jobs they otherwise wouldn't be able to, and purchase goods and services they wouldn't otherwise. I'm rarely a fan of government spending; but, roads, police, and firefighting are probably some of the least evil.
  - lhopki01 8y ago
    Why not public transport? Over the long term it's cheaper.
    - AlgorithmicTime 8y ago
      It's pretty inflexible. Public transit generally feeds into a hub from the outlying areas. If you need to go from one of the spokes to another, it will generally be incredibly inconvenient to make the trip via public transit. I don't see increased funding really fixing that.
  - CalRobert 8y ago
    Giving people an all-you-can-eat buffet of asphalt encourages extremely inefficient resource allocation. Doing this without asking for anything to offset the negative externalities exacerbates the problem. So far the negatives of increased vmt have been completely ignored - they are not minor. Ask yourself - would you enjoy living on a busy street, or a quiet one? A wide one, or a narrow one? Which would you rather see your kid walk or cycle to school on? Which will have cleaner air? More noise? Would you rather your 85 year old parents or grandparents had to walk across an 8 lane road or a 2 lane one to get to the post office from their home?
    - freehunter 8y ago
      You're comparing streets with roads, here. Fundamentally I agree with you, big roads divide communities and make cities unwalkable. But they are necessary. A street is made for transporting humans first and foremost. It has sidewalks, driveways to houses are accessed directly from the street, and pedestrians can cross with relative ease, to the point that crosswalks are basically unnecessary. A road is made for transporting cars first and foremost. There shouldn't be many residential driveways directly leading into a road, there may be sidewalks but they're not going to get used often, and you should rarely see pedestrians trying to cross. Crosswalks are very necessary on roads. There's no getting around the fact that we need roads. Cars and trucks need ways to move long distanced quickly. The problem becomes when city designers try to mix streets and roads (to make a stroad), leading to massive arteries running through the heart of a residential neighborhood. Proper city design puts roads outside of pedestrian-heavy neighborhoods and fills them with easily and safely walkable streets instead. There's nothing wrong with an 8 lane road, as long as that road isn't supposed to be used as a street as well. https://www.strongtowns.org/journal/2018/3/1/whats-a-stroad-and-why-does-it-matter https://www.strongtowns.org/journal/2018/3/1/whats-a-stroad-...
dawnerd 8y ago
A lot of people here in Portland don't seem to grasp that. They go, well adding an extra lane will just make that lane full... yeah... exactly otherwise whats the point of building another lane? Mass transit is a great idea in theory, but when it doesn't run 24/7 to areas you want to go or has a problem with homeless and other crazy people harassing you [1, 2, 3, 4] it just doesn't work out. A good solution for a lot of places with tight space is to just stack the highways. Doesn't make sense endlessly making roads wider on both sides - it can only go so far. 1. https://www.kgw.com/article/news/crime/trimet-barber-gets-2-years-for-cutting-womens-hair-in-public/283-454639803 https://www.kgw.com/article/news/crime/trimet-barber-gets-2-... 2. https://www.oregonlive.com/portland/index.ssf/2017/05/police_responding_to_ne_portla.html https://www.oregonlive.com/portland/index.ssf/2017/05/police... 3. http://www.wweek.com/news/2017/06/02/man-pummels-max-train-operator-while-screaming-about-first-amendment-rights/ http://www.wweek.com/news/2017/06/02/man-pummels-max-train-o... 4. https://www.oregonlive.com/portland/index.ssf/2018/05/crime_increases_as_trimet_weig.html https://www.oregonlive.com/portland/index.ssf/2018/05/crime_...
- Thlom 8y ago
  WTF. Mass transit is a great idea period. It works in numerous places around the world. Even if it doesn't run 24/7 or everywhere it runs most of the day and to many places. Meaning less cars and less need to "stack the highways"(!!!), meaning less space used for parking and roads and more space available for humans.
  - rplst8 8y ago
    It doesn't work for outlying areas. The further you get form a hub, the more varied the travel plans are. Express services work for connecting hubs. But it's the 30-60 mile out suburbs that are a challenge. Note, they are only a challenge if bureaucrats and big business continue to pour money into centralizing resources in giant cities. In a modern Internet connected economy, there is very little reason to colocate so many government services and large corporations.
- Broken_Hippo 8y ago
  Mass transit isn't perfect, so it shouldn't be had? That seems like flimsy logic when a number of the issues can be fixed. Move to smaller over-the-road mass transit for off-hours or have fewer busses. You don't need to have full-size busses at 2am when you can use the smaller busses that schools use at times, for example, or simply have a bus that runs once an hour. You can make sure that major employers are serviced by busses either regularly or at times when their shifts start and stop (factories, for example). You can use van-sized taxis for smaller areas and adjust the routes to meet needs in smaller areas or have electric, automatic trams that run at specific times through the day and less so at night. Intercity travel can be more restricted if the demand isn't there. Amsterdam has folks scan their ticket for the trams on their way out ... so they can see where folks are going to and from, in general, to better meet demand. Something like this can surely be done in different ways. Even more, you can create safe walking and cycling paths so folks are more likely to be able safely get to public transport. Have bus shelters many places. Perhaps don't expect it to make a profit. Perhaps tax vehicles to help pay for them when they are available to the user - after all, if you own a car when public transport will adequately fit your needs, the car is a luxury. Perhaps utilize more tolls to help pay for them. I've never had someone harass me on a bus where I am at now. In fact, I didn't have this issue in the states either when I was lucky enough to live in a place with busses. It would seem the solution would be to actually take care of folks that are homeless and mentally ill. It would make sense to call the police if someone is causing an actual disturbance to others. These aren't problems with public transportation, these are problems with society.

baddox 8y ago

How long ago were the lanes expanded? According to the general concept of latent demand, I would expect it to take perhaps a few years for the latent demand to manifest.

1123581321 8y ago
About two years. I agree it should continue to increase over the next several years as homes and businesses are located with the wider highway in mind. However, if latent demand takes too long to manifest, the lane expansion has saved driving time for a significant fraction of its life and shouldn’t be thought of as ineffective.
- TheCoelacanth 8y ago
  Adding a lane to an urban highway is immense. There is not only the cost of building the actual road, but the cost of acquiring the land which often requires displacing people from their homes via eminent domain and the cost of the disruption caused by the construction. Just providing some benefit is not enough to justify the cost; it must provide an enormous benefit.

repsilat 8y ago

Also: induced demand is a good thing. Even if travel time were the same with three lanes instead of two, that's 50% more people moving down that road. That's a quantifiable social benefit.

joe_the_user 8y ago
Even if travel time were the same with three lanes instead of two, that's 50% more people moving down that road. That's a quantifiable social benefit. Well, maybe those 50% achieve some benefit to themselves and society once they arrive at their destination. Keep in mind, if those people happen to be arriving at jobs they had previously, that's not a greater benefit than before. However, the movement of people down the road itself is a social detriment. Most people don't to spend time in traffic for kicks and the cost of fuel consumption, pollution, wear on highways and wear on cars is significant. I mean, if somehow I could spend only five minutes in my car per day and still get to my destinations, the benefit would clearly be far greater.
sjwright 8y ago
> That's a quantifiable social benefit. Only if you know how the occupants in these additional vehicles were transiting previously. If they were previously carpooling, or if they moved away from a good (but slightly less time efficient) public transport option, then the social benefit would be somewhere between minimal and nil.
- chii 8y ago
  But presumably the new occupants compared their existing old travel method, and deemed the new one better. If the old method had some "social benefits", it must mean that the old method's social benefit came at a cost in benefit to the occupants. Otherwise, they would not have chosen the new method!
  - JumpCrisscross 8y ago
    > the new occupants compared their existing old travel method, and deemed the new one better You’re leaving out the taxpayers subsidising their commute.

gascan 8y ago

There definitely seems to be a couple of functionally optimal road sizes, where extra pavement dramatically improves flow and by doing so at least appears to greatly improve throughput. In our town, the city has been switching from tight two lanes each way to one lane each way, plus turning lanes and bike lanes, and these new layouts are significantly more pleasant to drive with none of the old left-turn snarls of the past.