Reuters

Bike lanes could keep accident rates low, even without helmets.

Citi Bike, New York City's long-awaited bike share program, is launching in July. Earlier this month the program released a draft map of bike share stations; all told Citi Bike will boast 600 stations and 10,000 bikes. In short, the Citi is about to get a lot more Biki. So what does that mean for safety?

Two new studies illuminate potential public safety concerns that the city will have to consider as the bike share program gains popularity. The first is getting users to wear helmets. While state law only requires helmets for riders under age 14, Citi Bike encourages the practice among all users. The official bike share site even sends visitors to another city site that explains how riders can be fitted for and receive a free helmet.

Whether or not that effort will be sufficient is unclear. Both Hubway (Boston) and Capital Bikeshare (D.C.) also steer users toward nearby helmet vendors, yet a great deal of them still fail to helmet-up, according to research in press at the Annals of Emergency Medicine.

For the study, a group of doctors and medical researchers from the Boston and Washington areas observed more than 3,000 bike riders at 36 locations in September and October of last year. While roughly half of people riding their own bike wore a helmet, 81 percent of bike share users went helmet-less, the researchers report. All told, bike share users were 1.6 times less likely to wear a helmet than people who rode a personal bike.

Part of the disparity can be traced to what our Emily Badger has called the "cootie conundrum": a general reluctance to rent helmets from a vending machine near a bike share docking station. Cities can consider stricter helmet laws, but that means more enforcement, diverting resources from bike infrastructure, and could even discourage bike share use, which defeats the whole point. As the researchers writing in Annals conclude, the "optimal way to achieve higher rates of helmet use is not clear."

A second concern is whether more bike riders necessarily means more bike-related accidents. Or, to put it more precisely, whether the rate of bicycle accidents in New York will increase once the rush of bike share users hits the streets. The question is hard to answer conclusively, since the bike share movement remains in its infancy, but there's reason to believe that New York's abundant bike infrastructure will continue to mitigate the hazards of riding in the city.

In a recent issue of the American Journal of Public Health, a group of researchers led by Li Chen, who studies civil engineering at City College of New York, analyzed the impact of bike lanes on accident rates. Chen and colleagues tallied accidents before and after the installation of 43 miles of bike lanes across New York's five boroughs between 1996 and 2006. They also compared these rates to locations with similar traffic characteristics where bike lanes were never built at all.

The results are a bit complicated, but the researchers believe they shine a positive light on bicycle safety in the city. When Chen and colleagues modeled the differences between street types — in simple terms, compared those streets where bike lanes were added to those where they were not — they found that bicycle crashes seemed to increase a bit, but that this increase was not statistically significant.

"Our results indicate that the installation of bicycle lanes does not lead to an increase in crashes despite the likely increase in the number of bicyclists after the addition of such lanes," Chen and colleagues conclude. Moreover, the researchers think that if they had been able to control for the increased number of bike riders who emerge once bike lanes are built, they might actually have found a decrease in the accident rate. (The research, it must be pointed out, was funded by the New York City Department of Transportation.)

All things considered, the findings suggest that as long as bike share users stick to bike lanes — and as long as New York City keeps building bike lanes at pace with growing ridership — accident rates won't soar, even if the Citi Bike program becomes as popular as many predict. (To further decrease bike-car conflicts, the authors suggest creating "bike boxes" at intersections, so cars can become more aware of riders.) When it comes to biking in the city during the Citi Bike era, there may be some relative safety in numbers.

Photo credit: Chip East/Reuters

About the Author

Most Popular

  1. Design

    A History of the American Public Library

    A visual exploration of how a critical piece of social infrastructure came to be.

  2. Equity

    Berlin Builds an Arsenal of Ideas to Stage a Housing Revolution

    The proposals might seem radical—from banning huge corporate landlords to freezing rents for five years—but polls show the public is ready for something dramatic.

  3. A photo of a design maquette for the Obama Presidential Center planned for Jackson Park and designed by Tod Williams Billie Tsien Architects with Michael Van Valkenburgh Associates.
    Design

    Why the Case Against the Obama Presidential Center Is So Important

    A judge has ruled that a lawsuit brought by Chicago preservationists can proceed, dealing a blow to Barack Obama's plans to build his library in Jackson Park.

  4. Maps

    Mapping the Growing Gap Between Job Seekers and Employers

    Mapping job openings with available employees in major U.S. cities reveals a striking spatial mismatch, according to a new Urban Institute report.

  5. Design

    The Curious Politics of a Montreal Mega-Mall

    The car-dependent suburb it’ll be built in wants to greenlight Royalmount against the city government’s wishes but it needs them to pay for the public infrastructure.