MBA: Road Diet
What’s a road diet? Quite simply, traffic-calming expert Dan Burden told Streetfilms, “A road diet is anytime you take any lane out of a road.”
The first time people hear about a road diet, their initial reaction likely goes something like this: “How can removing lanes improve my neighborhood and not cause traffic backups?” It seems counterintuitive, but taking away lanes can actually help traffic flow smoother while improving safety for everyone.
Road diets are good for pedestrians: They reduce speeding and make vehicle movements more predictable while shortening crossing distances, usually through curb extensions or center median islands. They’re good for cyclists: Many road diets shift space from car lanes to create bike lanes. They’re good for drivers: Less speeding improves safety for motorists and passengers, and providing left-turn pockets allows through traffic to proceed without shifting lanes or waiting behind turning vehicles.
And here’s something to keep in mind during this era of lean budgets: Road diets are a highly-effective infrastructure improvement that can be implemented quickly and at low cost.
Streetfilms would like to thank The Fund for the Environment & Urban Life for making this series possible.
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Dan Burden: [00:11] A road diet is anytime we take any lane out of a road. If you have, say, four lanes and you knock it down to just two lanes, you’ve put the road on a diet. I first coined the phrase and used it in 1996 in an article that Peter Lagerwey and I wrote together. It had sticking power, people liked the term, they could understand what it meant. The most common road diet is converting four lanes to two and then putting in the third lane for turning. And then with the extra space adding in bike lanes.
Mike Sallaberry: [00:43] It’s a way to reallocate space so the street performs more efficiently. And it also allows spaces to be allocated for bicycle/pedestrian measures. As a motorist you have fewer lane changes and you now have a dedicated left turn pocket, so when you want to make a left turn, you have the space to do that and you don’t feel any pressure from behind to hurry up. And that improves safety for the motorist and pedestrians who are crossing the crosswalks.
Charles Gandy: [01:06] We’ve reallocated the space in the street to accommodate those that live here, that work here, that buy things here versus privileging those that would just drive through here fast. We used to have a sidewalk where the curb went right through here. We extended it all the way out, so we still have through two car travel lanes here, but we’ve shortened the distance for pedestrians by about 50%.
Dan Burden: [01:28] When you have a road diet, typically you have one lane in each direction, and now the prudent driver is setting the speed and not the imprudent driver. So crashes come down. Another real benefit is it makes it much easier to get across the street if you’re a pedestrian, you end up with less distance to cross. It’s quieter, and you end up with more people walking and bicycling. We typically see more people socialising. And generally we see the value of properties going up. One city that’s way out in front of other cities is San Francisco.
Mike Sallaberry: [01:59] San Francisco is up to about 40 road diets, which I believe is the most of any North American city. We have all sorts of road diets where we went from four lanes to three, three to two. We are working on one that goes from six to four. Back in the 1990’s Valencia Street was a four lane roadway and the Bicycle Coalition in particular wanted to have a bicycle facility on this street because it was already very heavily used by bicyclists. So the bike lanes went in as a trial. We went from four to three lanes with bike lanes and there is a report rate and after one year, we found that the number of cyclists increased by about 140%. And we were finding that the emergence along the roadway were actually very open to the idea of keeping the road diet.
Dan Burden: [02:38] After the road diets go in, because motorists are driving more prudent, people can shop for parking spaces, and the retail life of the street also improves. So the businesses typically do better after a road diet. To a lot of people it’s a surprise if you take half of something away, the number of lanes, that you actually end up with more performance for a street. And it just simply gets right down to the crunch of the numbers. In science, if you have fewer of something, it can be more efficient.
Mike Sallaberry: [03:08] Road diet is one of the most cost efficient ways to improve a roadway. You can do a mile of roadway for about $50,000, which is the cost of one sidewalk bulb out, or to compare it, a traffic signal could cost $300,000 or $400,000.
Dan Burden: [03:23] So we’re in New Haven looking at some roadways that are way overbuilt. We’ve got, as you can see, the road’s empty a lot of the time, and then all of this space in between these two roads on either side was at one time all housing, and they bulldozed all of it in order to put a freeway in. Well the freeway never came, never will come, and now we still have these very fast, very wide streets.
Speaker: [03:51] Earlier we were recording some cars that were going 50 miles an hour down this corridor.
Dan Burden: [03:56]
One major reason for road diets is safety. We’ve had several
people killed within a block of right where we’re standing now, doctors
who work here in the hospital. So we’re really looking at all
the ways we can get out those lanes we no longer need, which when you
have too many lanes you induce more speeding and more risky behaviour.
As we’re making the move back to cities, as people want to live more
and more in cities, so many of the streets in our cities, 30, sometimes
40% of the streets could operate better with fewer lanes. And
otherwise change the street back to a quieter version of its former
self. And it’s working.
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