In an effort to combat wasted space on our roadways, several streets in Louisville have been put on diets. In Louisville’s experience, these road diets typically shrink a four-lane street into three lanes with a central turning lane. The extra space can then be used for bike lanes or widened sidewalks.
Research has shown that redesigning our streets in this manner does not impact travel times, but does help promote safe streets and accommodate more road users. According to Gretchen Johnson and Aaron Johnson at FiveThirtyEight:
Bike lanes don’t cause a lot more congestion if you put them on the right streets. If you cut down the size of streets that are already near capacity, you’ll create severe congestion. But if you start with roads that are well under capacity, you’ll only increase the congestion a little bit. And it may not even be noticeable. Slimming down these roads that are too “fat” is known as a road diet — and yes, that is the technical term.
Looking beyond Louisville’s standard road diet reveals a number of different street design strategies. Here, urban planner Jeff Speck, author of Walkable City, worked with artist Spencer Boomhower to create an easy-to-understand video about the different types of road diets available to urban designers and traffic engineers.
As Louisville grapples with how to increase safety on its very deadly streets, we should look at how such road diets can improve our built infrastructure—especially arterials in the suburbs where a large portion of injuries and deaths occur.