In urban areas, public transit is a primary mode of transportation for people to commute to work, complete errands, and connect with their community. If transit isn’t reliable, people may choose other forms of transportation that could negatively affect riders, transportation agencies, and communities.
Dedicated transit rights-of-way (ROWs), such as bus-only lanes, improve reliability by enabling buses to bypass traffic congestion and maintain schedules. But establishing dedicated ROWs is a substantial and often costly undertaking. To gauge the real-world benefits of dedicated transit ROWs, the Minnesota Department of Transportation (MnDOT) sponsored a study led by CTS scholar Ying Song, an associate professor in the U of M’s Department of Geography, Environment, and Society.
“Many studies have found that attracting people to transit—and getting them to stick with it—depends a lot on its reliability,” Song says. “In addition to boosting ridership, reliable transit service can improve housing values, reduce travel costs, and improve job access along service routes. We wanted to determine how dedicated rights-of-way might be used in the Twin Cities to best harness these benefits.”
The research team’s goal was to learn how dedicated transit ROWs could improve reliability in the Twin Cities. They looked closely at specific stretches of road between bus stops rather than the entire transit system. This was a new approach, since most past studies focused on the impact of dedicated transit ROWs on the system as a whole, not on individual routes or segments.
To determine the benefits of a transit ROW, researchers computed route segment reliability using high-resolution automatic vehicle location and automatic passenger count data. They next conducted a spatial analysis to define bus service characteristics, operating environments, traffic conditions, and land-use features along route segments. Finally, they used a model to learn how these factors were related to transit reliability.
“Our model allowed us to identify the route segments in which a specific type of ROW, such as a bus lane, would improve reliability and benefit riders the most,” Song says.
By pinpointing specific routes that could benefit the most from a dedicated ROW, the study’s findings will help inform budget and priority decisions about ROW projects. Corridors that could realize the greatest benefits include Lake Street, Hennepin Avenue, and South 7th and 8th Streets through downtown Minneapolis.
“This project validated work that is planned and can serve as a valuable tool for determining what transit service would benefit from dedicated rights-of-way,” says Amrish Patel, a senior engineer with MnDOT’s Metro District. For example, Hennepin County has implemented bus lanes along Lake Street as part of the new Metro B line, which will serve the corridor beginning June 14.
The research also provided insight on which segments tend to be most (and least) reliable, along with the key factors contributing to reliability. Among the findings:
- Suburban route segments were the most reliable, likely because of light traffic in those areas.
- Commuter express route segments were the least reliable, possibly because they operate during morning and afternoon peak travel times with heavy traffic.
- Bus rapid transit routes were slightly faster and more reliable than local urban routes, even with more frequent service and higher ridership. This is likely due to signal priority and the design of stops along BRT routes.
Transit ROWs had different relationships with reliability: a higher ratio of bus lanes led to higher reliability, as did the presence of high-occupancy vehicle and high-occupancy toll lanes. The presence of shoulder lanes did not improve reliability significantly, as they may only help during congested periods. Other factors that boosted reliability were higher free-flow speeds, fewer traffic signals, and longer route segments.
In the future, the researchers plan to analyze additional routes to identify route segments in need of greater reliability. They also plan to create an interactive map with a more user-friendly interface for decision makers to examine the data and results.
—Megan Tsai, contributing writer
