When was the last time your city or town built a new, through street?

[massnative71]

Originally Posted by skeddy

more roads = more traffic funny how that works...

More traffic happens whether you build the roads or not. The Boston area is a perfect case study on why failing to expand infrastructure along with the growing demand, has been a mass failure.

[AtkinsonDan]

Originally Posted by skeddy

more roads = more traffic funny how that works...

more people = more traffic

Originally Posted by massnative71

More traffic happens whether you build the roads or not. The Boston area is a perfect case study on why failing to expand infrastructure along with the growing demand, has been a mass failure.

Correct!

[scorpio516]

Originally Posted by skeddy

more roads = more traffic funny how that works...

Originally Posted by massnative71

More traffic happens whether you build the roads or not. The Boston area is a perfect case study on why failing to expand infrastructure along with the growing demand, has been a mass failure.

Originally Posted by AtkinsonDan

more people = more traffic

Nah, it's a pretty standard urban planning rule - if you widen a road, it doesn't lessen traffic, traffic just fills the available space and actually more people start driving on them.
https://www.aeaweb.org/articles?id=1...aer.101.6.2616
https://trid.trb.org/view/1437757

It's called induced demand - when demand is created by increased supply. It doesn't make sense logically, but it's what happens.
The opposite is true too, if you decrease supply: fewer road lanes, decreasing road capacity, reduces traffic.

[massnative71]

Originally Posted by scorpio516

Nah, it's a pretty standard urban planning rule - if you widen a road, it doesn't lessen traffic, traffic just fills the available space and actually more people start driving on them.
https://www.aeaweb.org/articles?id=1...aer.101.6.2616
https://trid.trb.org/view/1437757

It's called induced demand - when demand is created by increased supply. It doesn't make sense logically, but it's what happens.
The opposite is true too, if you decrease supply: fewer road lanes, decreasing road capacity, reduces traffic.

That's a flawed (and now ancient) theory that has been widely debunked.



And FYI, fewer road lanes does not "decrease supply". If you want to do that, you need to either decrease the population or find a way to reduce the average commute distance.



Of course traffic can be mitigated by proper planning, or made worse by poor planning. Greater Boston is unfortunately a perfect storm of growing population, growing commutes, no increase in road/mass transit capacity. End result, the worst traffic in the entire country (by some measures).

[mp775]

Originally Posted by scorpio516

It's called induced demand - when demand is created by increased supply. It doesn't make sense logically, but it's what happens.
The opposite is true too, if you decrease supply: fewer road lanes, decreasing road capacity, reduces traffic.

It makes perfect sense logically. If you increase capacity, people will be less encouraged to carpool, take mass transit, or take discretionary trips at off peak times. Increased capacity also encourages more car-oriented development, which increases car trips. From the other end, wider roads with heavier traffic also actively discourage walking and biking, moving those people into cars.

[massnative71]

Originally Posted by mp775

It makes perfect sense logically. If you increase capacity, people will be less encouraged to carpool, take mass transit, or take discretionary trips at off peak times. Increased capacity also encourages more car-oriented development, which increases car trips. From the other end, wider roads with heavier traffic also actively discourage walking and biking, moving those people into cars.

In theory but not in practice. Again, the current state of eastern Massachuestts proves it totally wrong. Despite the lack of road capacity, people still drive. Because they have to and are given no other option. Boston is one of the worst trafficked cities in the country, with some of the longest commutes. Slow narrow roads clearly didnt prevent that from happening.

[mp775]

Originally Posted by massnative71

In theory but not in practice. Again, the current state of eastern Massachuestts proves it totally wrong. Despite the lack of road capacity, people still drive. Because they have to and are given no other option. Boston is one of the worst trafficked cities in the country, with some of the longest commutes. Slow narrow roads clearly didnt prevent that from happening.

The point is that investing in those other options are more effective than building more roads, because more roads can simply introduce more traffic.

[Lampert]

Originally Posted by massnative71

That's a flawed (and now ancient) theory that has been widely debunked.

Source?

[Boston Shudra]

Originally Posted by massnative71

Of course traffic can be mitigated by proper planning, or made worse by poor planning.

I do think that the stretch of I-95 from Peabody to Salisbury is proof that there's a limit to induced demand. Eventually you can reach a size of roadway where you eliminate traffic. However in major urban areas that upper limit is probably too large to be attainable/reasonable.

In other words, if I-90 were 15 lanes in both directions I'm sure it would never back up. However, of course the highway could never be that big and adding just 1 or 2 lanes would just encourage more people to use it and keep traffic levels similar.

[massnative71]

Originally Posted by Boston Shudra

I do think that the stretch of I-95 from Peabody to Salisbury is proof that there's a limit to induced demand. Eventually you can reach a size of roadway where you eliminate traffic. However in major urban areas that upper limit is probably too large to be attainable/reasonable.

In other words, if I-90 were 15 lanes in both directions I'm sure it would never back up. However, of course the highway could never be that big and adding just 1 or 2 lanes would just encourage more people to use it and keep traffic levels similar.

The focus should be around reducing bottlenecks, ie. the 95/93 interchange. Added capacity in targeted areas like that will have a substantial payoff. Despite the cost overruns and corruption it was notorious for, the Big Dig worked as intended. Even as traffic in the region exploded, the midday backups commonly seen on the old central artery have yet to be realized.