Reversible Lanes

DDOT Memo on Connecticut Avenue's Reversible Lanes

(scroll down to see the statistics about accidents on Connecticut Avenue, NW)



Transportation Policy and Planning Administration


TO: Karina Ricks, Manager Neighborhood Transportation Management Specialists

FROM: Jeff Jennings

DATE: September 28, 2007

SUBJECT: Connecticut Avenue reversible lanes


Connecticut Avenue located in Northwest Washington, DC has had a reversible travel lane since the mid 1950’s or earlier. There is little documentation on the actual date when the reversible lane began operating.

The reversible roadway on Connecticut Avenue is one in which the direction of traffic flow in one lane is reversed to the opposing direction for the period of time known as rush hour (7-9:30AM and 4-6:30PM). Its utility is derived by taking advantage of the unused capacity of the minor flow direction to increase capacity in the major flow direction. This is known as a 4:2 reversible operation (without parking) during commute hours. Although there is the need to construct additional lanes to add capacity, DDOT works off a grid system in an urban environment that precludes widening the existing roadway.

The Connecticut Avenue reversible lane was designed for accommodating the directionally imbalanced traffic associated with daily commuter periods.

The history of reversible lane systems (RLS) dates back more than 75 years and includes applications on all roadway classifications, from local city streets to freeways. Despite the long and diverse history of RLS, it is interesting to note that the practices that guide its application are not nearly as well defined or studied as many other techniques of traffic management.

Reversible lanes also have been used regularly in construction work zones, during major events and, more recently, for the evacuation of major metropolitan regions threatened by hurricanes.


The apparent reason for using a reversible lane on Connecticut Avenue is to add capacity.

It has not been practical, and is not possible, to add lanes to the existing roadway to increase capacity. The most important factor that has been influencing the operation of the reversible lane is the volume of vehicles that use it. There are over 38,000 vehicles per day that travel Connecticut Avenue.

Connecticut Avenue is a six lane roadway with the reversible lanes occupying about 3 miles of it. The reversible lanes have boundaries of Livingston Street to the north and Woodley Road to the south.

Additionally, a needed separation to maintain a safe operation between opposing traffic streams has never been installed. There are prohibitive costs and overwhelming logistical concerns in creating such a system.

The ratio of major traffic volumes had to be a factor upon the design and implementation of the reversible lane on Connecticut Avenue. However, there is significant volume in each direction during many hours of the day.


The safety of the Connecticut Avenue reversible lanes remains a major concern. From 2004 to 2006, there were over 750 reported vehicle crashes on Connecticut Avenue. That is an average of about 1.5 crashes per day. Additionally, over 10 pedestrians were involved in crashes during the same time period. Within the operating time of the reversible lane, there were 270 vehicle crashes.

Driver confusion is cited as a concern with the reversible lanes. Drivers who are unfamiliar with the reversible lane system tend to have no knowledge of the boundaries and the associated turn restrictions with the reversible lanes.

Lastly, many drivers have a tendency to exceed the posted 30MPH during the morning and evening rush while the reversible lanes are in effect.


The reversible lanes create a constrained environment with restricted turn movements during the morning and evening rush hours. The opportunity for better access is regarded as a positive step for businesses along the 3 mile stretch. Eliminating the lanes may also enhance business activity near the street.


The Connecticut Avenue reversible lanes have achieved an operational objective but not without serious consequences. Lack of safety for vehicle drivers and pedestrians is indicative with the Connecticut Avenue reversible lanes. There is a detrimental quality of life for the surrounding neighborhoods to the reversible lanes.

Furthermore, the economic development aspects of removing the reversible lanes are attractive and may provide an added pulse to the businesses along the corridor.

Safety Data Relating to Reversible Lanes in Washington, DC from the DDOT Report, "Reversible Lanes -- The Washington, DC Experience"

    • 45% of all accidents in the reversible lane sections on Connecticut Avenue, NW take place while the reversible lanes are in operation.
    • On Wisconsin Avenue and Massachusetts Avenue, where there are no reversible lanes, the accident rate was 27% and 25%, significantly less than on Connecticut Avenue, NW
    • Between 2003 - 2006 there were 16 head-on crashes in the reversible lanes.
    • Moving violations (red light running, left turns from the middle lane, driving in the wrong late) are highest on Connecticut Avenue when the reversible lanes are in operation.

You can read Bill Adler's article about the reversible lanes at

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Read about how Washington, DC would be like if it was a more pedestrian friendly city: