What exactly is being proposed by a Better BRT?
The Better BRT plan calls for reducing Route 29’s current travel lane widths by one foot (1’) in most areas. Currently, Route 29 north of Sligo Creek Parkway carries at least six travel lanes, with the standard widths being 12′ right lanes and 11′ center/left lanes. Implementing Better BRT on Route 29 would involve narrowing the right lanes from 12′ to 11′, and narrowing the other lanes from 11′ to 10′ to save at least three feet of room on either side of the road, and six feet total.
Use the slider on the street cross section below to compare the lane widths of the existing conditions versus of Better BRT plan.
Are narrow lanes safe?
In urban settings with pedestrians and local cross streets, narrower lanes can actually improve safety! When designed correctly, roads with lane widths less than 12′ increase driver awareness and discourage speeding, resulting in less severe collisions. For urban arterials such as Route 29 south of Tech Road, the Federal Highway Administration recommends lane widths of 10′ to 12′.
Narrow lanes are not always safer: they can be dangerous on roads with speed limits greater than 45 mph, undivided highways (i.e., roads without a median) and controlled-access freeways. The Better BRT plan does not propose lane narrowing north of New Hampshire Avenue (Route 650) for these reasons.
Are 10-ft wide lanes used on Maryland state roads?
Lanes widths of 10′ and 11′ are common throughout Maryland state-maintained road network. In fact, Route 29 already has 10′ wide lanes between Sligo Creek Parkway and downtown Silver Spring.
Another state road with 10′ wide lanes and significant amounts of commuter, bus, and truck traffic is Route 1 in Hyattsville, College Park, and Beltsville. However, Route 1 did not always have narrow lanes: the State Highway Administration narrowed the lanes on certain segments from 12’ to 10’ in the 1970s to create a center turn lane out of the existing 48’ curb-to-curb width due to excessive rear-end collisions caused by cars stopping in the left lane to make left-turns.
Can large vehicles drive on narrow lanes?
The maximum allowable vehicle width by the Federal Highway Administration (FHWA) is 102″ or 8.5′. This is a foot and a half narrower than the narrowest proposed lanes in this plan. As shown in the figure below, even with outside mirrors included, vehicles such as trucks and buses typically do not exceed 10’ in width. A guided busway may minimize the width required for the bus lanes.
What about Connecticut Avenue in Chevy Chase? Doesn’t it have really narrow lanes?
Yes, but that is not what is being recommended by the Better BRT plan.
Connecticut Avenue (MD-185) in Chevy Chase is an anomaly in the Maryland road network. South of East-West Highway (MD-410) Connecticut Avenue’s lanes are just 8-9′ wide, with most being about 8.5′ wide. The distance between the curb and the median on Connecticut Avenue south of Bradley Lane is just 26′ on each side; five feet narrower than the width of the curb to the median proposed on Route 29 under the the Better BRT plan (31′). The lanes on Connecticut Avenue are so narrow that the State Highway Administration (SHA) bans heavy trucks on the road south of MD-410.
The lane widths on Route 29 under the Better BRT plan will be nowhere near as narrow as those on Connecticut Avenue and will have enough room for cars, trucks, and buses.
Further reading
More information about lane widths can be found on the following websites:
- Federal Highway Administration, US Department of Transportation
- National Association of City Transportation Officials
- Academic Articles
- Potts, I., Harwood, D., & Richard, K. (2007). Relationship of lane width to safety on urban and suburban arterials. Transportation Research Record: Journal of the Transportation Research Board, (2023), 63-82.
- Harwood, D. W. (1990). Effective utilization of street width on urban arterials (Publication No. 330). Transportation Research Board.
- Karim, D. M. (2015). Narrower lanes, safer streets. Canadian Institute of Transportation Engineers Annual Conference.
- News/Blog Articles
- The Urbanist: Let’s Talk About Lane Width
- CityLab: Why 12-Foot Traffic Lanes Are Disastrous for Safety and Must Be Replaced Now
- CityLab: When Adding Bike Lanes Actually Reduces Traffic Delays
- World Resources Institute: Bigger Isn’t Always Better: Narrow Traffic Lanes Make Cities Safer