Bike lanes experiment measures cyclist response to infrastructure design

According to the Pennsylvania Department of Transportation (PennDOT), Philadelphians were involved in 740 crashes between 2011-16—killing 20 cyclists and causing a major injury to 80 more.

For pedestrians, those numbers are measured in the hundreds. Thus, making cycling safety not just a problem but, increasingly, a priority.

Enter, Megan Ryerson, an assistant professor of city and regional planning at PennDesign, research director of the $14 million PennDOT-funded Mobility 21 transportation research center, and, uniquely, director of a brand-new project that attempts to document not just these crashes, but the many more near-crashes that happen every day.

Her pilot study, launched in October 2017 as a course alongside PennDesign students, is, to her knowledge, first-of-its-kind research that uses eye-tracking glasses—purchased with a seed grant from the Perelman School of Medicine to support interdisciplinary public health research—to study the movements of urban bikers who use the city’s bike lanes. The first 10 volunteer bikers for that test, vetted for their cycling skill level, rode a loop around University City from 30th Street to 45th Street, using the parking-protected Chestnut Street bike lane and the buffered-yet-unprotected lane on Walnut Street. During their ride, participants wore glasses equipped with inward- and outward-facing cameras that measure pupil dilation, head movement, where they were looking at any given time, and how long they held a gaze.

The research is the kind of field-to-spreadsheet data that may allow for building, if not exactly a leisurely experience for urban bikers and pedestrians, then at least a safer one.

“Cyclists—and I’m a cyclist—know protected bike lanes are safer, but why?” muses Ryerson, also an assistant professor in the Department of Electrical & Systems Engineering in the School of Engineering and Applied Science. “The only metric we as planners have now about safety is crashes. Imagine being able to analyze intersections or roadways, for example, by how much stress and uncertainty they create for cyclists and correlate that with crashes. It gets us much more nuanced data about our urban infrastructure.”

It is significant, then, that the pilot includes real bikers, in real situations, in real bike lanes. The study documents not just crashes that make morning headlines, but the ones that nearly happened but go unreported. Ryerson says her research adds a new, quantifiable layer to the field of study.

“My method can generate empirical proof of things we might anecdotally know,” she says, though careful to caution the research is still in the proof-of-concept stages.

But there were a few key takeaways from the fall 2017 data. Prime among them are that bikers are constantly looking around for threats while in an unprotected lane—thus, susceptible to hitting pedestrians or potholes—while those in the protected lane were less intensely focused ahead, but more at ease.

Bikers also spent a lot of time looking down or to the right—potholes and fast-moving car traffic on the right makes this a necessity. Yet, in University City, Ryerson notes, many signs require bikers to look up and to the left.

“Signs should be placed where cyclists are looking at them—on the ground,” she says. “The preliminary results show that cyclists aren’t looking at the signs, such as on Chestnut and 33rd streets when cyclists need to know the bike lane is moving from the left side to the right side of the street. Our results can help the city understand when and where they should stripe to provide critical information to cyclists. Overall, what I hope to do here is start to evaluate Philadelphia’s infrastructure and question, ‘What are the interventions that would improve safety and navigation here, based on how different travelers take in information?’”

The current crop of results, in that sense, are just the beginnings of bigger research.

For the spring 2018 semester, with a team of eight students, Ryerson is testing the soon-to-come protected bike lanes on South Street and a portion of Lombard Street between 27th and 21st streets. This go-around, because of the construction schedule for the lane, she is able to test the bike lane before and after being transformed into a protected bike lane, for more precise data of how the intervention improves the quality of life for bikers and what signage is working.

Moreover, thanks to a grant from Penn Medicine, Ryerson has been able to invest in lightweight, top-quality, wireless eye-tracking glasses, allowing for even sturdier results than the fall 2017 pilot was able to provide.

But it’s not just a matter of Penn Medicine gifting glasses,” she says. It is, symbolically, a promising new approach to urban design as a public-health intervention.

“There’s ‘not getting hit by a car,’ the base-level public health goal of mine, but then also the idea of public health creating healthy people and healthy environments to promote more active lifestyles,” Ryerson explains. “That reduces obesity, health issues, improves quality of life, and provides access to opportunities.”

Healthy environments as a design principle, she says, is the idea that creating a safer intersection promotes a “spiral” of completely improving a neighborhood. People feel safe, so they feel good about their neighborhoods, and, therefore, they do good: They clean up streets, start neighborhood groups, and maybe advocate for a new speed bump on their street. From a public health standpoint, this encourages low-mobility neighbors—particularly the elderly, who Ryerson says can be discouraged by design details as seemingly minor as a traffic light that turns over too quickly—to spend more time outside.

In truth, Ryerson says it was a surprise that Penn Medicine was willing to invest in a transportation project—though a delightful one, of course.

“We had the traditional cardiac disease pitches and air pollution pitches, and they were all interesting public-health pitches, but then in came Megan and she was really sort of out of the wheelhouse of what the committee had been addressing, but unbelievably compelling and so passionate about what she was doing,” says Jennifer Pinto-Martin, executive director of the Center for Public Health Initiatives and part of a Penn Medicine Strategic Plan 2.0 subcommittee tasked with awarding funds for West Philadelphia public-health interventions. “She made such a strong case for why safe mobility is one of the biggest problems we will continue to face. She wowed the committee.

“This, I thought, is someone I want to know.”

Flaura Winston, a Penn Medicine public health researcher also involved in the committee, says the award came as part of a two-year project to develop impactful interventions in Philadelphia.

“What’s so cool about this is there’s no place else we can think of, except for Penn, that can be such a great place for studying this,” Winston says. “It brings together the School of Design, the Medical School, Engineering, CHOP—all within a couple blocks with very complicated roads, bikes, trains, a highway, pedestrian crosswalks. All these great things are here where we can study and not just understand, but also make Philadelphia safer.”

In a practical sense, Winston says solutions may involve getting a better understanding of how safe intersections around the Hospital of the University of Pennsylvania are. That could, in theory, inform how much more at-home care the hospital decides to offer patients with low mobility.

Looking ahead, Ryerson hopes to develop a testing lab at the Pennovation Center for the biking experiment. Due to the difficulty of testing actual interventions in real-world settings, she says the thought is to take insights from field testing and use a lab at the center to test with signage, paving, and more. Those results can be shared with the city’s Vision Zero initiative, which Ryerson has already begun consulting and collaborating with, as it pushes toward eliminating all traffic-related deaths in Philadelphia by 2030.

“One of our missions, with Mobility 21, is to do research with impact,” she says. “I feel really committed to that mission, and I’m working with the city on defining research questions where the outcome can truly be of value to their decision-making. It’s exciting to be in this role—to have a research team, and support and find partners who I can empower with answers to their questions.”

Carrie Sauer, a PennDesign graduate student involved with both semesters' studies, says the big-picture goal is to better take advantage of the city's infrastructure and landscape, uniquely suited to biking with its flat geography, narrow streets, and density. It's a city ripe to be more navigable, but also safer--“a city with good biking bones,” she says.

“We're not quite Copenhagen,” Sauer says, laughing. “There are a few people who’ve studied abroad in these cities and mention them, but the rest of us are like 'Well, bicycle highways are cool, but let’s focus on how to make Philadelphia’s streets safer for all modes and all types of users.’

“We don’t need to turn Philly into Denmark, but we can feel safe biking to school.”

Photo at top: Carrier Sauer, research assistant for PennDesign assistant professor Megan Ryerson’s bike lanes pilot research, is cut off by a school bus while cycling in the 27th and South streets bike lane earlier this year.

Homepage photo: PennDesign assistant professor Megan Ryerson, who leads a pilot study measuring cyclist behavior in both protected and unprotected bike lanes, bikes along Walnut Street in a buffered but unprotected bike lane.