Those Weird Curves on the New Bike Lanes Are Just Good Design

By John Hennelly

If you build a bike lane, people are gonna talk about it. One comment I hear a lot about the new bikes lanes along Chicago Ave. is why do they do that weird curve at each intersection? To slow down bikers? For pedestrians? Or just because?

There is a reason, and it is a good one. By having the bike lanes kick out at intersections they create space between the lane and right turning cars. This helps drivers better see bikers (and pedestrians), and have a chance to stop before they hit them. 

Compare the bike lane at Chicago and Church, across from Whole Foods, with the bike lane at Sherman and Church, by the Barnes and Noble. At Sherman, eastbound drivers must look back over their right shoulder, through their car (and its view-obstructing roof support), past parked cars, and peer down the bike lane, to spot a trailing bicyclist. While doing this they must still worry about pedestrians and other cars. This is hard for even the most conscientious driver. 

In contrast, the Chicago/Church intersection makes it much simpler for drivers. First, bikes have a separate light, and are not to cross when cars are turning right. Nor are cars to turn when bikes have the green light. But even if someone were inclined to break the traffic rules (it does happen), there is good visibility and room to stop and avoid a crash. 

Second, the curve adds just a few feet of space, but an important few feet. Intersections are where most crashes happen, often when cars are turning right. Here’s why: drivers look left when they turn right. It seems counterintuitive, but it is natural: that is where the traffic is coming from. Many drivers never even glance to their right, the direction they are headed, until they have started their turn. This is poor behavior, but pervasive. No law will change it. But good design can help prevent injuries. 

The new lanes are well-designed, and the weird curves are part of that good design. We need more of the same, and not just for future bike lanes. The city should reconfigure busy intersections across the city so pedestrian crosswalks are offset in the same way the Chicago bike lanes are. This would make life safer for everyone on the street.