In 2007, WMATA and DC introduced several measures to improve service in the 7th Street/Georgia Ave. corridor: Metro Extra Route 79, signal priority at 28 intersections, and bus lanes on 7th street and 9th Streets downtown. Some of them have helped, while others have failed. Why?
Signal priority was introduced on the corridor for Route 79 only, but has only yielded a 1.5% time savings per trip and those results were not deemed totally reliable. That’s because DC and WMATA tried a one-size fits all approach.
Each of the 28 intersections provide the same 10 second green extension in either direction. They also can’t be triggered more than once every ten minutes in both directions combined — a bus northbound that triggers it will then prevent southbound buses as well as northbound buses from taking advantage for 10 minutes.
The bi-directional approach means that buses traveling counter-flow may trigger the signal when the need for extension is in the peak travel direction. Bus stops were also not relocated to take advantage of the signal extension.
Stop location has been another impediment to reaping the full benefits of signal priority as no stops have been relocated to take advantage of the extra signal time. The photo shows a crowded bus stop at Georgia and Kennedy that regularly causes buses to miss the light. Moving the stop to the far side would take better advantage of the signal priority.
The experience in Portland where they installed a similar system with 55 intersections on a single route may provide some insight. They not only added signal priority, but included special lanes, curb extensions and stop relocation. The Portland pilot routes experienced a 10% reduction in travel time in the peak period, peak direction and an 8-10% improvement in on time performance.
They found that they had to analyze mounds of data and do an intersection by intersection analysis to determine the correct signal phasing and stop location. They found that similar appearing intersections are not similar at all. They found that close cooperation between the staffs of traffic and transit agencies was an absolute necessity and found that the process is incremental and takes time to reach the final objective.
The 7th Street and 9th Street bus lanes also provide lessons. The lanes are not well designed. It is not clearly marked where cars are permitted to enter the lane to make right turns. Bus lane signage prohibiting autos could also be improved.
Enforcement has also been poor to nonexistent. The District needs to pass a specific ordinance to prohibit cars from bus lanes and it needs to settle on enforcement mechanism(s), such as cameras mounted on bus shelters similar to speed and red light cameras, or assigning of ticket writers specifically to enforce the lanes.
The 9th Street lane has been largely a failure due to very few buses using the lane, poor lane design and no enforcement. In contrast, the proposed ¾-mile stretch on I Street from 13th to 19th St NW has an average of 30 buses per hour and the time savings per bus would be close to 3 minutes per bus. With good enforcement and design, an I Street lane could make bus travel much more pleasant and speedy while saving money at the same time.