My comments on the Longfellow Bridge reconstruction

Note: the report on which I commented is online at this address:

Comments must be received by tomorrow, so you still have time if you really hurry!


March 19, 2012
Pamela S. Stephenson,
Division Administrator,
Federal Highway Administration,
55 Broadway, 10th Floor,
Cambridge, MA 02142

Attention: Damaris Santiago

Re: Longfellow Bridge reconstruction, MassDOT Project File No. 604361

Dear Ms. Stephenson:

I think you for the opportunity to comment on this project. I also accept most of the responses to my comments of May 7, 2009 [in the project report linked above], and I am especially pleased that two-way bicycle access across the bridge will be maintained during construction. I support the preferred alternative, with a few exceptions which I will note in this letter.

I am also especially pleased that the preferred alternative maintains flexibility for changing volumes in different modes. As the price of fuel continues to rise, increasing use of light motorcycles, electrically-assisted bicycles and motor scooters is to be expected. A roadway accommodating all of these avoids the awkward issues that arise when vehicle types are segregated by a curb or barrier.

I am concerned about the following issues, most of which I also addressed in my earlier comments (included in the project report — I am, however, identified there only as “bike rider.” My credentials are available for review at

I agree with the lane positioning in Option 1 at the Boston end of the bridge, which has motorists merging across the path of bicyclists who are headed for Cambridge Street, but I am concerned with the proposed bike box installation.

Bike boxes are a trendy concept which directs bicyclists to swerve in front of motor traffic. Without a special traffic signal, the proposed bike box offers no way for bicyclists to know when the motor traffic will start to move on a new green. Motorists are required to look back for bicyclists, at the very time when attention needs to be focused on traffic ahead. This is troubling. Also, experience with bike boxes already installed in Boston shows that motorist encroachment is endemic. I am not convinced that bicycle traffic volume will be so high as to require any storage option other than the bike lane itself, and a right-turn lane with shared-lane markings

The pedestrian plaza to between the inbound lanes and the Storrow drive off-ramp is within the scope of the project, but I see no discussion of how inbound bicyclists will transition from the road to the new bicycle-pedestrian bridge over Storrow Drive. There needs to be a ramp from the inbound lanes angled toward approaching bicyclists.

I also see no mention of a crosswalk on Charles Street between the Storrow Drive off-ramp and Charles Circle at one end, and the traffic island east of Charles street and the other. This would greatly decrease pedestrian travel time and could also serve bicyclists who are uncomfortable with riding around the circle. The crossing must in any case be signal-protected, as traffic cannot flow from the bridge and the off-ramp at the same time.

I disagree with the following response to my earlier comment suggesting a bike lane against the median in Charles Circle:
Bicycle traffic approaching the bridge outbound from Charles Circle will be able to negotiate the intersection and join the bicycle lane on the right side of the bridge with limited conflicts.

Four lanes of heavily-used off-ramps that diverge to the right do not constitute “limited conflicts”. As in my earlier comments, I suggest instead that bicycle traffic on Cambridge Street approaching the bridge be directed to continue at the left, adjacent to the Red Line station. Then there is only one conflict, with traffic turning left onto Charles Street – but this traffic is relatively light and slow. A bike lane on the left side of a one-way roadway is not novel or unusual. There is one on Commonwealth Avenue in Boston, and there are many in New York City.

The report includes a voluminous discussion, with numerous illustrations, of the Boston end of the bridge. There is only a brief discussion, with a couple of illustrations, of the Cambridge end. Neither illustration extends west far enough even to show the full scope of the project. Yet there are very serious issues of traffic safety at the Cambridge end.
The proposed outbound bike lane to the right of the off-ramp to Memorial Drive at the Cambridge end is a deadly hazard. Bicyclists will be traveling at speeds up to the 30 mph speed limit as they descend from the bridge. Motorists preparing to turn right will have to look behind themselves to the right, and in their rear-view mirrors, in the hope of seeing bicyclists in time to avoid collisions, at the same time they need to look ahead to negotiate their way onto the off ramp and yield to pedestrians in a crosswalk. Motorists will have to stop in the travel lane, blocking all following traffic, to yield to bicyclists.

This is the same type of conflict which resulted in a bicyclist fatality in Portland, Oregon, and led to the elimination of the right turn option for motorists, see

A rash of such fatal collisions is occurring in cities around the world which have placed right-turning motor traffic to the left of through-traveling bicyclists. A traffic signal with separate intervals for bicycle and motor traffic would in theory resolve the conflict, but would result in serious delay for both modes, and scofflaw behavior. Removing the right turn from the Longfellow Bridge would lead to significant inconvenience, and displaced traffic.

More-knowledgeable bicyclists will merge left out of the bike lane to avoid the conflict. A right-turn lane to the right of the bike lane, or discontinuing the bike lane before the ramp and installing shared-lane markings, could encourage this behavior. These solutions do not, however, serve the novice and child bicyclists whom the project is intended to attract.

A more promising option, as I described in my earlier comments, is the continuation of my proposed left-side bike lane to run alongside the Red line reservation on the bridge. This option would completely avoid the conflict at the Memorial Drive off-ramp and other conflicts downstream in Cambridge. The next conflict would then be at Third Avenue, where much bicycle traffic will in any case be turning left across a plaza onto Main Street. Before reaching that point, bicyclists would have a long stretch in which they could merge to the right to continue on Broadway.

It is to be anticipated that there will be considerable bicycle traffic on the bridge sidewalks, and especially on the wide promenade on the outbound side. Transitions to/from these and the parklands either side of the bridge will be of special interest to casual and recreational bicyclists, and their safety and convenience need to be addressed. I am especially concerned about the stairways leading down from the bridge sidewalks into parkland. Bicyclists can easily fail to notice that they are approaching a flight of stairs from the top. I suggest not only signage, but also partial barriers, suitable to be traversed by pedestrians, though not by bicyclists.

As I said at the start of these comments, I am pleased with the basic elements of the preferred options; and I also note that none of the changes I propose require structural changes to the bridge or its approaches.

Very truly yours,

John S. Allen

cc: Thomas F. Broderick, P.E.,
Acting Chief Engineer,
MassDOT Highway Division,
10 Park Plaza,
Boston, MA 02116,
Attention: Kevin Walsh,
Project File No. 604361.

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