Considering a New Way to Combat Traffic
guest post by Larry Cole
Transportation planners often say we cannot build enough roads to fix congestion. In fact, building new roads or expanding existing roads accommodates growth but can also encourage people to move farther out. The result is more people driving longer distances, more carbon emissions, more wasted time in traffic. This effect can be amplified when increased traffic on widened roads lessens the desirability of established neighborhoods.
We believe that there is a better way. This week, we will present the Planning Board with preliminary recommendations for a countywide transit network. Our goal is to increase the appeal of transit serving our activity centers, such as Silver Spring, Bethesda, White Flint, and Germantown, and to move people faster.
The recommended transit corridors would accommodate all-day service with 10- or 15-minute wait times, stations or stops every half-mile or mile, and high-quality vehicles that resemble streetcars rather than traditional buses.
As always when considering public transportation, we estimated the number of potential riders. Sparsely populated areas donâ€™t warrant frequent transit service, but densely populated activity and employment centers generate a greater number of transit riders in a smaller space and warrant more frequent service by high-quality transit. Pairing high-quality transit with growing mixed-use centers brings truly sustainable development, by making the best use of available road space. Itâ€™s also more sustainable from the standpoint of County finances since these high-density mixed-use centers also generate the highest tax returns per square foot, lessening the need for subsidies for transit service.
Where Should We Place Transit?
While it makes sense to put transit where people are and want to be, fitting it into existing roads will be a challenge. Our recommendations identify roads within first-ring communities inside and near the Beltway, as well as along the I-270 Corridor, where we could convert travel lanes to bus service.
As we considered where to place BRT service, we concluded that it made most sense to work within our existing master plan rights-of-way by repurposing existing lanes to serve transit, which will minimize impacts to property owners. By working within our existing roadway pavement wherever possible, we can avoid large capital costs, environmental impacts, and the problem of induced traffic. Where we can move more people in a travel lane via transit than private automobiles, we believe that repurposing lanes is a more sustainable solution than obtaining more land and constructing new lanes.
In our analysis, the threshold for dedicated lanes was 1,000 passengers per hour in the peak direction in the peak period. In areas with lower levels of forecast transit demand, we recommend that buses generally operate in mixed traffic but prioritized at traffic lights.
Our studies showed:
- Highest forecast ridership (49,000 riders a day) along MD355 between Friendship Heights and White Flint. Dedicated lanes or a dedicated busway would provide frequent all-day service in this corridor.
- To accommodate high ridership on more commuter-focused corridors we recommend a mix of options. For example, along US29, with 17,000 forecast daily riders we recommend a mix of dedicated lanes (south of Lockwood Drive), mixed traffic (on Lockwood Drive and Stewart Lane in the area of the White Oak Transit Center), and a median busway north of Stewart Lane.
We ran our transportation model both with and without a test of lane-repurposing on segments of four corridors: MD355/Rockville Pike, MD97/Georgia Avenue, US29/Colesville Road, and MD650/New Hampshire Avenue to determine the relative impacts on transit ridership, vehicle miles traveled (VMT), and vehicle hours traveled (VHT) in the year 2040. Our results varied by area but were generally favorable, and the benefits were greatest in the down-County area; in Silver Spring alone, VMT would be reduced by six percent.
Sufficient forecast ridership is needed to justify transit, but we need a pedestrian-friendly environment to succeed in attracting that ridership. Safe, handicapped-accessible pedestrian facilities are needed at a minimum, but so are attractive shelters and landscaping, and sufficient bike access to the stations. Refining the standards for these items is one of our tasks for the next phase of our work.
The master plans in some of our activity centers set an ambitious goal of up to half of all travelers using alternative transportation modes â€“ transit, walking, cycling, carpooling â€“ rather than driving alone in a vehicle. Half of all travelers is a large share, but this goal is grounded in our desire for long-term sustainability. BRT is perhaps the best option to get us there and we recommend moving quickly to implement transit improvements on the corridors where we currently have the highest demand.