man on bike in dense city traffic

Seattle residents were shocked when they discovered how much two new bike lanes in the downtown core cost to build — about $12 million per mile. Were the new lanes gold-plated? In a city suffering constant disruptions by major construction projects and beset by routine gridlock, people are quick to judge transportation projects.

Can a $12 million-a-mile bike lane be justified, or is it as bad as it sounds?

What’s in a Lane?

They aren’t exactly gold-plated, but these bike lanes are not your parents’ bike lanes. Before 2010, the design guidelines that transportation engineers followed rarely included accommodations for cyclists. If they did, the bike lane was to be created by painting a stripe three feet inside the curb.

In the U.S., the theory of “vehicular cycling” dominated both cycling culture and urban design. Cyclists were supposed to bike like they were driving a car. They were told to take space in the car lane and cycle fast enough to keep up with motor vehicles. Most people are not capable of and often not interested in riding this way. In America, cycling became a niche activity. Meanwhile, people of all ages comfortably pedaled through European cities.  

Then, in 2010, the National Association of City Transportation Officials (NACTO) began to study bike lane designs from around the world and across the United States to develop the Urban Bikeway Design Guide. They copied the success of bike-friendly cities like Copenhagen and Amsterdam.

The new guide called for protected bike lanes, dedicated light signals, and routing bike lanes behind bus stops. Cities that adopted the new standards experienced significant increases in urban cycling. Around the country, construction of modern, protected bike lanes costs between $133,170 per mile and $536,680 per mile.

Seattle’s Bike Lanes

In Seattle, where traffic is better than Los Angeles but worse than Dallas, residents have plenty of incentive beyond the regular benefits of cycling to get out of their cars. But everything in Seattle is expensive (even more so than LA), and that includes bike lane construction. For example, traffic control for lane closures during construction of one of the bike lanes cost a quarter of a million dollars.

Still, these two bike lanes are expensive even by Seattle standards. The discovery of sinkhole-prone soils added $2.4 million to one project; retrofitting streetlights and adding traffic signals accounts for 40 percent of the cost of the other project. The city’s department of transportation director acknowledges that the city could have used a less aggressive design. He admits some choices, such as building raised walkways alongside the lane, may not have been worth the additional cost.

Calculated Costs, Externalized Savings

In Copenhagen, ranked the best city in the world for cyclists, the cycling population contributes $261 million in public health savings each year. That’s enough to pay for their protected bicycle infrastructure in under five years.

Even greater, but harder to quantify, is the potential for saving lives.

Seattle’s new lanes have only been open a short time, but they already have had a measurable effect. Along their routes, vehicle collisions decreased from 4.6 per month to 2.5 per month — none of the crashes involved bikes.

Seattle had experienced three bicycle fatalities in 2016, with a 16.5 percent overall increase in serious bicycle injury collisions. Statewide, more than half of Washington State’s fatal and serious injury bicycle crashes in 2017 involved factors like bicycles riding on the road, indicating that protected bike lanes are key to reducing cyclist fatalities.

Even though safe, modern bike lanes usually cost less than Seattle’s new lanes. But the results show the city is right in thinking that the benefits of bike lanes are priceless.

By Gemma Alexander

Gemma Alexander has an M.S. in urban horticulture and a backyard filled with native plants. After working in a genetics laboratory and at a landfill, she now writes about the environment, the arts and family. See more of her writing here.