Secret habits of timid cyclists studied

If you're a cyclist who rides fewer than four days a week, Jennifer Dill would like to track your movements using satellite technology.


Published August 15, 2007 by The Oregonian
By Patrick O'Neill

Urban transportation – A PSU researcher's GPS units will reveal local routes used by less-confident riders

If you're a cyclist who rides fewer than four days a week, Jennifer Dill would like to track your movements using satellite technology. Dill, a transportation researcher at Portland State University, wants to see how moderate cyclists use Portland city streets and bike paths in hopes of boosting the use of bikes as alternatives to cars.

The study also will help planners understand more about the value of bike lanes, a subject examined in a previous Dill study that showed the number of bike lanes within a quarter-mile of a person's home had no bearing on the amount of cycling the person did.

The new study drills deeper using global positioning system units. During the past few months Dill has captured the movements of more avid cyclists, issuing 130 of them GPS units to carry on trips around the city.

After it's analyzed, Dill hopes the data will help show city bike planners where to locate bike paths, bike lanes and directional signs to help riders find their way. In this second phase of the GPS research, Dill wants to get a snapshot of the routes that less-frequent cyclists use to get from place to place.

For this phase of the study she's looking for cyclists who are at least 18 years old, live within the Portland-area urban growth boundary and don't ride bikes for a living. She'll choose just one volunteer per household.

Dill shares a cozy office with her Breezer Uptown 8, a purple commuting machine that she often rides to work at Portland State University's Toulan School of Urban Studies and Planning.

If it were up to her, a lot more people would share offices with their bikes. Dill says the locators will fill in crucial gaps in knowledge she has gained about bicycle use from telephone surveys of 566 Portland-area residents.

The units record the rider's location, speed and direction every three seconds. The volunteers carry a GPS device for a week, turning it on every time they climb on a bike.

Surveys are useful, Dill says.

"But there's only so much people can remember about their rides," she says. With the GPS units, she says, "We'll know how far and how fast they're going."

And most important, which routes they travel. The devices enable the researcher to draw a computerized map of each trip.

Participants also log in the reasons for their trip and weather conditions at the time.

Roger Geller, bicycle coordinator for the Portland Office of Transportation, says Dill's research will add important knowledge about the patterns of bike use in the city. Geller said the city has surveyed bicycle use extensively and has maps of the most popular bicycle routes.

"But we don't have data on the intensity of the use," he said. "Jennifer's study will tell us that."

In addition, he said, the GPS data will give planners a more precise idea of the lengths of bicycle trips.

So far, Dill said, most of the volunteers have been experienced cyclists. But in recruiting several hundred more riders for the study she hopes to find those who have less experience and self-confidence. That will give her an idea of the differences in the choice of routes between experienced cyclists and those who are more fearful of riding in traffic.

Dill hopes to find out how far cyclists will go out of their way to travel on streets where there's less competition from cars.

Do cyclists choose different routes in different kinds of weather? The study will show that, too.

The GPS study likely will help answer another puzzling question: How much do bike lanes encourage people to cycle on the streets?

"The jury's still out on the amount to which bike lanes contribute to cycling," Dill said.

"I'd hope we'd find out what types of infrastructure the city should build to get the most bicyclists," she said. "Bike lanes work for some but not for others."

Her GPS study could show the relative popularity of bike lanes and "bike boulevards," neighborhood streets that can be used as cycling routes where cars are few and slow.

Knowing the lengths to which cyclists will go to avoid heavy traffic is important. Almost half of noncyclists would like to take up bicycling if there weren't so much traffic, Dill found. And most of those who ride bicycles would ride even more if it weren't for competition with cars.

Dill and others say more people could be lured onto bicycles if only they knew how to find back streets, mostly free of traffic, that would take them where they wanted to go.

A survey by the Portland Office of Transportation found that 67 percent of respondents had at least some interest in getting on a bike. Of those, 7 percent characterized themselves as "enthused and confident" and less than 1 percent called themselves "strong and fearless" in traffic.

Other surveys have found that the fear factor is a major deterrent to cycling among those who were interested in riding but concerned about their safety.

The Robert Wood Johnson Foundation, which promotes research into health-related fields, supported the study to figure out how the built environment affects bicycle riding and how to encourage physical activity.

Support for the second part of the GPS study comes from the Oregon Transportation Research and Education Consortium.

Patrick O'Neill; 503-221-8233;