Maps of traffic stress show where improvements can help build a better bicycle network.
City streets can be scary places, especially when you're on a bike and everyone else is rushing past you in cars. Our streets can also be deadly places: in 2010 [PDF] 618 U.S. cyclists were killed on roads. Fully one-third of bike fatalities happen within intersections. The prospect of getting smashed into the asphalt keeps all but the most fearless cyclists off of many city streets. Scary streets mean a less bikeable city.
"Nobody wants to ride their bike in the left lane of a six-lane road with 40-mile-an-hour traffic. It's crazy," says Peter Furth. He's a civil and environmental engineering professor at Northeastern University and co-author of a new report out from the Mineta Transportation Institute that looks at how varying levels of "traffic stress" on different city streets can limit where people are willing to ride.
Furth and his colleagues mapped out the different levels of stress on the streets of San Jose, California, and they find that while many streets are calm enough for most riders, they're sliced up by streets with high levels of stress. High-stress streets are measured as those with high speed limits, limited or non-existent bike lanes and signage, and large distances to cross at intersections.
The map below shows how high stress streets create islands of low-stress bikeability that are disconnected from each other.
Though 67 percent San Jose's streets were measured as low or very low stress streets by Furth and his colleagues, 20 percent were measured as high stress streets. These are the main traffic corridors and major roads that help connect the city. But for bicyclists, a low-stress ride across town basically does not exist.
"The difference between bicycling and other modes of transportation is that if you aren't willing to risk your life on a dangerous road, you often simply can't get from here to there," says Furth.
Furth says that much of the problem has to do with typical transportation planning in the U.S., where streets are designed primarily as pathways for cars to move across as quickly as possible. The residential streets that make up most of a city's road system are much more amenable to bike riding than the larger traffic streets, but when residential meets arterial the network of bikeability is breached. That means fewer parts of the city are easily connected and fewer people are likely to consider a bike as a viable transportation option for going across town.
But the stress levels that create these barrier can be reduced. Furth and his colleagues note that with a modest investment, the city of San Jose could dramatically improve the connectivity of its bike network. Suggested improvements include traffic calming measures, intersection safety measures like median refuge islands, bike lanes and separated cycle tracks.
The maps below show the parts of town that can access the campuses of San Jose City College and San Jose State University using only low stress streets, and how that could change if the suggested improvements were made. The low-stress bike network expands significantly.
These improvements are just suggestions to prove a point, and Furth and his colleagues haven't penciled out the specifics of how they could be paid for or built. But he argues that most of the suggestions have low or moderate costs. "Even the higher cost solutions are still an incredible bargain, 10 times less expensive than the kind of infrastructure we do for transit or highways," Furth says.
A previous study looking at his hometown of Brookline, Massachusetts, found that the city's streets could become a nearly complete low-stress bike network at a cost of $20 per person per year for about a decade. That's comparable to what bike friendly countries like Denmark and the Netherland spend, but it's a long way off from what's currently spent on bicycle infrastructure in the U.S.
"At the federal funding level, we're spending between 50 cents and 75 cents per person," Furth says. "It's a drop in the bucket."
Kicking that up a bit could help bring about the sorts of improvements many cycling advocates clamor for. But making the jump from 50 cents to $20 per capita isn't likely to happen any time soon. Using maps like these, the little money that's available can be better targeted to improve a city's bike network. That may not turn everyone into a fearless urban cyclist, Furth says, but it could help make the city streets seem a little less scary.
Top image: weegeebored/Flickr; Maps courtesy Mineta Transportation Institute