#18 – Contraflow Bicycle Lanes on Urban Streets

Cambridge, Massachusetts

Cara Seiderman, Transportation Program Manager, Cambridge, MA


Cities that have extensive one-way street systems can be very frustrating for cyclists to maneuver, especially because they often are more affected by major detours or out-of-the-way travel than motorists, both because the time difference is greater and because the alternative routes are often more stressful or less safe. In addition, because of the inherent greater flexibility of the bicycle, many cyclists will simply ignore the one-way restrictions and travel against traffic, particularly when traffic volumes and speeds on the preferred route do not present a deterrent.

Sign indicating contraflow bike lanes on Scott Street. Bike lane is highlighted with blue pavement.

There are some options available in looking at ways to accommodate cyclists on one-way street systems. Many cities and towns in Europe explicitly allow cyclists to travel in both directions on a one-way street. This usually occurs on very narrow streets with very slow traffic, typically in the core areas of older cities and towns. Another option is that specific designated facilities be created to permit travel in the opposite direction. The contraflow bike lane is a designated facility marked to allow bicyclists to travel against the flow of traffic on a one-way street.

There are, of course, safety concerns associated with contraflow bike lanes. Motorists and pedestrians do not expect bicyclists to be traveling in the opposite direction of traffic on one-way streets. However, contraflow bike lanes have been used successfully in some cities in the United States (Boulder, CO; Eugene, OR; Portland, OR; Madison, WI). Building on evaluation criteria developed for Eugene, OR, the city of Cambridge looks at the following conditions when evaluating a potential contraflow lane location:

In addition, the following features should be incorporated into the design of the street with the contraflow lane:

It is preferable also to have a separate bike lane in the direction of motor vehicle traffic, striped as a normal bike lane. Where the roadway width does not allow this, bicyclists will have to share the road with traffic.


There now are four contraflow bicycle lanes in Cambridge: on Concord Avenue between Follen Street and Waterhouse Street (often referred to as “Little Concord Avenue”); on a portion of Waterhouse Street off of Mass. Ave (it is a very short stretch without much evaluation information so this will not be discussed here); on Scott Street between Beacon Street and Bryant Street; and on Norfolk Street south of Broadway. These contraflow lanes meet the criteria detailed above, although Norfolk Street was somewhat of an exception in that not many cyclists were riding against traffic on this street.

1. Concord Avenue

In 1994, a major street renovation project created changes in the street pattern in the area of Arsenal Square. This route is a direct connection for east-west travel in the city as well as a main route from one part of the Harvard University campus to the main campus. Concord Avenue not only provides the most direct connection, but also allows cyclists to avoid riding on a street with major traffic and no space between the travel lanes and the parking lanes. It also allows cyclists to avoid riding in an underpass where cars reach speeds of up to 50 mph (the city speed limit is 30 mph).

Concord Avenue contraflow bike lane.

Larger numbers of cyclists already were traveling in both directions on this one short block of a residential street to make the direct connection. There are only two driveways for single-family residences along the street.

A 1.5 m (5 ft) contraflow bicycle lane was created with two solid white lines, bicycle symbols and arrows at very frequent intervals. The reason for using white rather than yellow, which one normally would use to separate the directions of traffic, is because there is parking between the contraflow bike lane and the curb, so motorists needed to be permitted to pull over and park in the direction of travel. A stop sign for cyclists was put up at the end of the block so that cyclists would look for traffic before proceeding across the street.

Signs were installed on the approach to the intersection. The intersection is a non-conventional situation, more of a bend in the road than a real intersection. Motorists must proceed slowly. The street is a U-shaped one, only serving residents along the street, and has very low traffic volumes (under 1000 VPD).

Sign indicating contra-flow bike lanes on Norfolk Street.

Scott Street bike lanes.

2. Scott Street

Sewer construction and roadway paving on this street offered the possibility of implementing traffic calming and other changes. Scott Street offers a direct connection between a minor arterial that is one of the area’s most used bicycle travel corridors and Harvard University, Harvard Square, and other destinations. It is a wide one-way street with little-used parking on both sides. A contraflow bike lane was marked and blue thermoplastic included to remind motorists to look for cyclists and not to drive in the bicycle lane. A sign was included, stating “Do Not Enter Except for Bicycles.” Traffic volumes are less than 2,000 vehicles per day.

3. Norfolk Street

One block of this one-way street was striped as a contra-flow lane to allow cyclists to avoid an arterial street without shoulders or bike lanes and with large traffic volumes, including trucks. A sign with a graphic representation of the contraflow lane was installed at the intersection entering the street. Blue thermoplastic was added to each end of the lane to call attention to its presence. Traffic volumes are below 2,000 vehicles per day.

Evaluation and Results

No formal evaluations have been done for these streets. City staff have observed the locations, Cambridge Bicycle Committee members, and members of the traveling public have offered comments, and we have performed before and after bicyclist counts for two of the streets. Cyclists are continuing to use the streets in both directions and are using the designated contraflow lanes.

On Concord Avenue, some cyclists have been observed riding in the contra-flow lane but in the direction of traffic, despite the extremely frequent occurrence of arrows. Anecdotal comments are that the lane has bike symbols, so it seemed to those traveling the wrong way that they were supposed to be in that lane.

On Concord Avenue, there is also a sight-line issue created by a combination of the angle of the street and a private property fence. Concerns were reported by regular users of the street and additional signs were put up to remind motorists to watch for bicyclists.

Scott Street counts

Before and after counts were performed for cyclists riding on Scott Street. These showed an increase of cyclists riding against traffic (using the contraflow lane in the after counts). Given origins and destinations in the area, it would be expected that more people would be using the contraflow lane in the morning peak period, and this was affirmed in the data (see following table).

Before and After Scott Street Contraflow Lane Bike Counts
AM Peak Hour
Before 20 peak, 16 traveling southbound (against traffic), 4 northbound (with traffic)
After 34 peak, 30 traveling southbound (in contra-flow lane), 4 northbound (with traffic)
PM Peak Hour
Before 17 peak, 4 traveling southbound (against traffic), 13 northbound (with traffic)
After 19 peak, 7 traveling southbound (in contra-flow lane), 11 northbound (with traffic)

Concord Avenue counts

Before and after counts are not exactly comparable because they were performed at different times of the year. However, the counts consistently showed that there were about the same number of cyclists in both directions of travel, before and after. Peak hour counts were about 62 cyclists (occurring at midday rather than morning or night, presumably because of the student population).

Conclusions and Recommendations

Contraflow bike lanes can be used successfully in circumstances similar to the ones described here if they meet the criteria outlined. There may be additional designs or circumstances that would merit testing as well.

Pavement markings and signs should be thought through carefully in the design. It is preferable to implement the lane when longer-lasting pavement marking materials can be installed (thermoplastic or in-lay tape). Otherwise, a strict maintenance program to keep paint highly visible will be required. Bicycle symbols and arrows should be created at frequent intervals (far more frequently than standard AASHTO recommendations). Consideration should be given to adding color (blue is most visible) in the lane. Signs should be installed wherever motorists would be approaching the street (at the beginning of the intersection and at any intersecting roads or major driveways).

Where there is room for bike lanes on both sides of the street, they should be included to clarify where cyclists should travel. If there is no room for a full bike lane, other pavement markings or signs should be considered to clarify direction.

Costs and Funding

In general, the costs for implementing a contraflow lane are fairly straightforward and easy to calculate when they involve standard pavement markings and signs. The costs would increase somewhat from a standard bicycle lane because it is preferable to use more frequent bicycle symbols and arrows as well as more signs. Additionally, some signs might be custom-made rather than standard. Costs would increase if blue thermoplastic paint is used.

Sample costs for Cambridge in 2002:

Thermoplastic Bike Symbols $80 each
Thermoplastic Bike Arrows $60 each
Inlay Tape Bike Symbols $200 each
Inlay Tape Bike Arrows $150 each
Blue Preformed Thermoplastic* $10.00/square foot
*Not including installation — All others include installation


Cara Seiderman
Transportation Program Manager, Cambridge, MA
Environmental & Transportation Planning
Community Development Department
Cambridge, MA 02139

Wayne Amaral