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Dedicated Bicycle Lanes Reduce Injuries & Fatalities 9 June 2019

Researchers at the University of Colorado Denver and the University of New Mexico say infrastructure built specifically for bicyclists make roads safer for everyone. “Bicycling seems inherently dangerous on its own,” says co-author Wesley Marshall, an assistant professor at the College of Engineering, Design and Computing at CU Denver. “So it would seem that a city with a lot of bicycling is more dangerous, but the opposite is true. Building safe facilities for cyclists turned out to be one of the biggest factors in road safety for everyone.”

The study was published recently in the Journal of Transport & Health. One of its key findings is that bike facilities act as “calming” mechanisms on traffic, slowing cars and reducing fatalities. The effect is similar to the effect of grid blocks found in cities with higher intersection density, according to a report by Science Daily.

The researchers investigated over 17,000 fatalities and 77,000 severe injuries over a 13-year period in large US cities like Denver, Dallas, Portland, Oregon, and Kansas City, Missouri. During those years, the United States saw a 51% increase in bicycling to work and the number of protected bike lanes doubled each year starting in 2009.

Originally, researchers believed that more bike lanes and an increase in the number of cyclists would lead to a “safety-in-numbers” effect — the more cyclists on the road, the more likely drivers would slow down and be aware of their surroundings.

Instead, they found that safer cities aren’t due to the increase in cyclists, but due to the infrastructure built for them — specifically, separated and protected bike lanes. They found that such dedicated bicycling infrastructure, which separates motor vehicle and bicycle traffic, is associated with fewer fatalities and better road-safety outcomes.

Portland, Oregon saw the biggest drop in fatalities. Even though the number of bicyclists more than tripled between 1990 and 2010, the road fatality rate dropped by 75%. With added bike lanes, fatal crash rates dropped in Seattle by 60%, in San Francisco by 49%, in Denver by 40% and in Chicago by 38%.

“The U.S. is killing 40,000 people a year on roads, and we treat it as the cost of doing business,” Marshall said. “A lot of the existing research focuses on bicycle safety. With this study, we’re interested in everyone’s safety. Focusing on fatalities — not crashes — is important,” says Marshall. “Over the years, my research has found that safer cities have fewer fatalities but more fender benders.”

Co-author Nicholas Ferenchak, assistant professor in the department of Civil, Construction and Environmental Engineering at the University of New Mexico, says he hopes this study simplifies the ways in which cities move forward. “When we believed it was the old safety-in-numbers concept, that meant we had to figure out how to get more people on bicycles to make a city safer. That’s not easy. But this research has boiled it down for city planners: create cycling facilities, and you’ll see the impact.”

As this study focuses on larger cities, the results may not apply generally to smaller cities. But creating physical separation between bicycle riders and motorists has to be a no brainer for anyone interested in protecting those who choose to ride two wheel vehicles from harm. u