What makes vehicles—cars, buses, and bikes—behave?

If streets aren’t formalized for vehicular movements (such as in this intersection in Bangladesh), vehicles can’t be expected to behave predictably.

By Steve Price

We structure streets for cars, which makes streets safer for motorists and reduces their risky behavior. We paint lines to define travel lanes and put signals at intersections to tell motorists when to stop and go. We install tall street lighting so motorists can clearly see the road ahead. If you take away all that formalized street design for cars, chaos results. By contrast, we generally do not formalize streets to improve bicycle behavior, yet I frequently hear from motorists that bicycle riders are out of control. Our streets are not designed to encourage bicycle riders to follow rules. Predictable bicycling behavior takes more than painting bicycle sharrow stencils on streets.

Researchers in Denmark analyzed video footage of travelers’ behavior at major intersections and found that 14 percent of bicycle riders violated basic traffic rules—lots of bicycling on sidewalks. But when separated bike lanes were present, that dropped to under 4.9 percent. It also found that 66 percent of motorists violated traffic laws, most frequently by exceeding speed limits. Research conducted elsewhere in Europe also found that bicycle riders don’t deserve their bad reputation. Why the bad rap? Bicycle riders’ careless behavior is easier to notice (e.g. riding on sidewalks or going the wrong way on a one-way street) whereas speeding by motorists or driving while texting is harder to notice. In recent years more cities are installing bicycle lanes, but this often stirs up the ire of motorists, many of which think this is prioritizing bicycles over cars, but formalizing a street for all users makes the street safer for all.

Formalizing street for car behavior does nothing for bicycling behavior.