Marc Lefkowitz | 09/09/16 @ 11:00am
There’s evidence that road diets have a positive effect on traffic crashes while addressing important questions of equity and climate change, an official with the Federal Highway Administration told a group in Cleveland this week.
Road diets—defined as the “narrowing or elimination of travel lanes on a roadway to make room for pedestrians and bicyclists”—are a hot topic as cities strive for a balance between vehicle access and improving a street’s livability and safety.
For the last 50 years, the trend was to widen roads. The data on that mass movement to “add capacity” suggests conditions got worse, says Keith Harrison, an engineer and safety expert with FHWA. He led a session on implementing road diets to mostly traffic engineers and public works officials at the Northeast Ohio Areawide Coordinating Agency.
"A street is a place," Harrison said, "it's not just serving a transportation function. We can see in it an opportunity to improve economic activity, livability, and the presence of biking and pedestrians."
He pointed to a groundbreaking 1999 study performed by Tom Welch, an official with Iowa Department of Transportation who compared 12 road diets with cases of road expansions from two to four lanes. The results showed how widening roads pumped up traffic volume by 4% and induced 14% more crashes.
There was no remedy until road diets first appeared in the early 1980s in places like Billings, Montana and Seattle, Washington. Since then, more than a thousand road diets have been completed and evaluated. A national database of all the road diets completed in the U.S. shows a safety improvement overall. Ohio participated in a ten state study of road diets by the Highway Safety Information System. Thirty road diet sites in suburban locations produced an average of 29% reduction in crashes, the study found, with some cases reaching a 70% reduction.
Still, road diets are met with skepticism -- usually, merchants and local residents who worry about a loss of on-street parking. In places that are resistant to change, safety is not enough to brush aside hyper local resistance to, for example, swapping parking for bike lanes, Harrison claims. Seattle was able to raise rates of cycling dramatically after a road diet, but it was the outreach and diffusing the resistance of a stubborn few that made all the difference, he added.
If one can characterize the attitude of the mostly suburban and small town traffic engineers at the NOACA workshop, they seemed on board and willing to advocate for road diets. The work to be done, Harrison confirmed, is in reaching out to neighborhood leaders and the old timers who like to perpetuate myths that road diets can’t work and will only make traffic worse when the data shows the opposite is actually the case.
For a great set of resources on planning and implementing road diets, visit the FHWA Road Diet area online.