How data leads to more bike lanes

Andrew Zaleski Issue 2 0 Comments

Five bridges span the Schuylkill River near Center City, and since 2005 the Bicycle Coalition of Greater Philadelphia has counted bike traffic on all of them. In that time, cycling rates have increased by 260 percent — 870 bikes crossed the river per hour during peak times in 2013, according to the Coalition’s count — but the strongest show of cycling takes place on the South Street Bridge, and for one reason: It’s the most bike friendly.

By contrast, bicycle traffic on the Market Street Bridge has fallen. Per the Coalition’s 2014 report, the reason is obvious: “Ridership on all bridges shows a direct correlation with the quality of bicycling infrastructure.” Therefore, the presence of bike lanes and bike racks tends to increase the number of cyclists counted during the annual tallies.

But does the equation work in reverse? Does counting data — trends in ridership gleaned from tallying cyclists during rush hour on weekday mornings — ever dictate where new cycling infrastructure gets built?

“You’re never going to find a one-to-one linear path between any piece of data and a transportation investment,” says Greg Krykewycz, who manages transit, bicycle and pedestrian planning for the Delaware Valley Regional Planning Commission (DVRPC). “Where the data comes in is in giving us a really nice way to understand usage, and then we can figure out whether we were right or not after we build the infrastructure.”

In other words, cycling infrastructure hews closely to a “Field of Dreams” methodology: If you build bike lanes, cyclists will use them. More lanes attract more cyclists, which in turn could potentially attract even more lanes. Of course, it’s not like any of this goes through ordinary people’s minds as they pedal out on their daily commutes.

“We generally find that when you build bike facilities, the bike traffic generally doubles. But we’re looking at trends as opposed to, ‘Well, a bike facility should go here,’” says John Boyle, research director at the Bicycle Coalition. “The reason that you put a bike lane on 10th Street as opposed to 11th Street, it often doesn’t come down to how many people are bicycling on each street. It’s more about what’s compatible.”

Sometimes it comes down to plugging the holes in existing cycling infrastructure. This is a job for Jeannette Brugger, a senior transportation planner with the Philadelphia City Planning Commission and the city’s new lead pedestrian and bicycle coordinator. Bike lanes are built when roads are repaved, Brugger explains. This happens in small segments that don’t always align with cycling infrastructure goals.

“Two to three times a year, with lists from PennDOT” — the Pennsylvania Department of Transportation — “we look on the bike/ped plan where the priority infrastructure gaps are, and then we say what’s going to be paved this year or on the horizon,” Brugger says. “We see where those overlaps are and try to build them into the plan.”

On occasion, cycling data fits into the mix. Last September, the Mayor’s Office of Transportation and Utilities received a $300,000 grant from the Commonwealth Financing Authority’s Multimodal Transportation Fund to fill in cycling infrastructure gaps. Brugger says that local count data played a role in allocating the state money.

“When we had to decide where to put the infrastructure that will be funded by this $300,000, we looked at DVRPC count data,” she says. Most of the funding will go toward repainting existing bike lanes and installing new bike infrastructure in the Center City area.

Overall, though, cycling data is still too new to accurately predict where corresponding infrastructure should go.

“We have [car] traffic data going back 50 years, and we have an understanding as an industry how that data trends over time and how to use it,” Krykewycz says. “We don’t have that on the cycling side. All of this data tells part of the story, but we don’t have the ability yet to understand how many more people are going to bike on a street if you add a bike lane. That’s what we’re working our way up toward.”

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