Making cities bikeable

Bicycles are the most efficient mode of transportation for traveling short distances. They occupy less space on and off the road; there are no greenhouse gas emissions; and they help keep cyclists healthy. Yet most cities don’t design bicycle infrastructure in a strategic manner that improves mobility for everyone on the road—cyclists, drivers, and even pedestrians.

Using Pittsburgh as a testbed, Sean Qian, a professor in civil and environmental engineering at Carnegie Mellon University, is manipulating large transportation datasets to reveal information that will make the city more “bikeable.” In 2017 he will provide cyclists with road and transit information to improve safety and reduce their stress, and furnish city officials with smart options for spending scant bicycle infrastructure funding.

The first arm of his research evaluates how safe it is to cycle in Pittsburgh by analyzing 911 incident reports and PennDOT crash data. By looking at where and when accidents happened and deducing their frequency, Qian can tell which streets are safer for cycling. Other metrics that play into his analyzes are hourly traffic volume, vehicle speed, the grade of the streets, and bus coverage. All these factors contribute to stress that cyclists experience. For example, a cyclist on their way home from work, may find it unsettling to navigate Pittsburgh’s steep hills during rush hour. Or, if a thunderstorm pops up, that cyclist may want to load his bike onto a bus that’s outfitted with a bike rack and head home.

Using a variety of datasets, Qian is building a website that will tell riders the safest route from Point A to Point B, based on personal preferences. Cyclists will enter their trip specifications, such as starting and stopping points, time of day, desire for flat terrain, etc. The system will then calculate “bikeability scores” for various routes. The scores will help cyclists choose routes that suit their needs. Qian’s approach to providing route guidance is different from other mapping applications because it considers matters that are important to cyclists, such as safety, ride easiness, and the other factors reflected in the bikeability scores.

The second part of Qian’s research deals with improving bike infrastructure. In addition to considering the monetary costs of building bike lanes, he is studying the social costs. For example, if a car lane is converted to a bike-only lane, how will that affect the flow of vehicle traffic? Will it create more congestion? If bike lanes are built near local retail areas, will that increase business in our communities?

Qian is developing an optimization model that will help the city determine the best ways to spend money on bike infrastructure, while evaluating the pros and cons for bikes, cars, and pedestrians. His work will uncover the most cost-effective places to build new infrastructure or where to convert car lanes into bike lanes, all while evaluating the safety and social implications of these changes.

Qian’s work is well underway, and the website is projected to launch in 2017. Deployment partners for his research are the City of Pittsburgh, BikePGH, and Pittsburgh Bike Share. While Qian is focusing on Pittsburgh, his research will serve as a model for other cities.