Wednesday, April 25, 2012

Bikes on the Mass Ave Bridge: Riding in the Street vs. A Protected Path

By: Kevin Carr

The Harvard Bridge along Massachusetts Avenue, commonly referred to as the Mass Ave Bridge, connects Boston with Cambridge across the Charles River.  It consists of a four lane roadway, with two approximately 10 foot lanes in each direction, a roughly 5 foot bike lane in each direction, and 8.5 foot sidewalks on each side.  The bridge is one of the major connections between Boston and Cambridge, and carries roughly 50,000 vehicles across the Charles River every day.  The Mass Ave Bridge also has one of the few entry points to the Charles River Esplanade park , and carries high volumes of pedestrians and cyclists during the warm summer months.

Riding in the Street:
Providing bike lanes in the street is standard in many parts of the U.S.  Some people believe that it is actually safer to ride a bicycle in the street with motor traffic.  Bike lanes were put in on the Mass Ave bridge in order to give cyclists an area to ride without interference from pedestrians, and to reduce the number of bikes on the sidewalk, making the sidewalk better for pedestrians.

Riding in a Protected Path:
Providing protected paths for cyclists, usually referred to as cycle tracks, is common in many parts of Europe, such as the Netherlands.  They are much less common in the U.S. because they are believed to be more dangerous than riding in the street. However, they have been proven to work extremely well in Europe. In The Netherlands, for example,  27% of all trips are made by bicycle, while in the U.S., only 0.9% are.  The sidewalk on the Mass Ave bridge offers the separation and protection of a cycle track, but really acts like a shared use path because the area is shared by both cyclists and pedestrians.

Bikes on the Mass Ave Bridge:
A large percentage of cyclists choose to ride on the sidewalk across the Mass Ave bridge, protected from motor traffic, instead of in the bike lanes. Also, the sidewalk offers an entrance into the Esplanade park while the bike lanes do not. In order to get an idea of how the cyclists were distributed, I decided to collect some data.  Over a half hour period on a warm, sunny Friday afternoon (April 20th), I recorded counts for which area cyclists chose to ride across the bridge: on the protected sidewalk or in the bike lane.  The results are shown in the table below:

As you can see, only 7, roughly 10%, more cyclists chose to ride in the street than on the protected sidewalk.  Riding in the street across the Mass Ave bridge is fairly high stress.  There are 4 lanes of heavy traffic that are usually traveling above the posted 30 mph speed limit.  The lanes are somewhat narrow, and a cyclist can feel squeezed between the fast moving traffic and the guardrail of the sidewalk. The truth is that only an experienced cyclist will feel comfortable in this high stress cycling area. The sidewalk, on the other hand, is very low stress. The biggest obstacle for riding on the sidewalk is avoiding pedestrians. When riding across the bridge, a cyclist will usually encounter several pedestrians or groups of pedestrians. On a nice day, a bike may encounter 10 or more groups of pedestrians when crossing the bridge. However, it typically isn't a hassle for a cyclist to avoid pedestrians.  Since the sidewalk is fairly wide, at 8.5 feet, there is usually plenty of space for a cyclist to navigate the pedestrians. You can see how much space there is in many of the pictures. Only a large group of pedestrians that blocks virtually the entire sidewalk will cause a conflict where a cyclist will have to slow down or stop until the group moves to the side. I also noticed that cyclists travel in both directions on the sidewalks, but only travel in the designated direction with motor traffic in the bike lanes.

By creating bike lanes like this, instead of protected cycle tracks, many users are neglected, such as children and other less experienced or less aggressive riders.  These users would not feel safe riding in the bike lane next to motor traffic.  

Bicycle facilities should be designed to accommodate all users. Bike lanes are better than nothing, but they do not meet the needs of all cyclists, only the minority group of experienced riders. If we had more attractive facilities to all users that were separated from motor traffic (cycle tracks), there would be a much higher percentage of people using bicycles for transportation. This would benefit our society in many ways: less people would be driving cars so we would reduce our emissions and traffic congestion, and they would be getting more regular exercise, which would lead to better overall health and a decrease in obesity rates.


  1. They desperately need to make the bike lanes more attractive and safer on this bridge.

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