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Some questions for the
Cambridge bicycle program

October 9, 1995

[ I am not sure whether I distributed this to members
of the committee, but it does represent the concerns
I was articulating at the time]

The Cambridge bicycle program is planning a celebration for October 14, for the opening of the new bike lanes. Let's get to the point: I don't think that we have much to celebrate.

In my opinion, some fundamental questions about the program's approach and underlying goals need to be answered. The program's first major products -- both on the streets and on paper -- reveal a seriously confused approach.

The goal of the program should, in my opinion, be to improve conditions for bicycling. This is to be distinguished carefully from two other approaches:

to be anti-car, seeing bicycling as a tool for reducing use of cars and thereby improving urban social structures and land use, reducing air pollution, etc. etc. In the anti-car view, improving conditions for bicycling is undertaken as a means to other ends, when it serves those ends.

to encourage people to ride bicycles even when this involves measures which actually worsen or do not improve conditions for bicycling. This "the ends justify the means" approach leads to larger numbers of bicyclists but with no corresponding improvement in their behavior, accident rate or acceptance by society.

I see strong elements of confusion, and of the two mistaken approaches in the program's actions, and they disturb me. Now, for some specifics:

The Mount Auburn Street bike lane doesn't cut it!

Why not?

It's a poorly designed and conceived one.

The most shocking thing about it is that it has one block over which almost its entire width is within the range of opening doors of parked cars. How do we increase bicyclists' safety by instructing them to ride in a parking lane where car doors can open in front of them at any time?

A bicyclist died in Roslindale several years ago running into a car door. Though the Bicycle Coalition has been trying to get one passed for years, there is no law in Massachusetts requiring motorists to look before flinging their doors open. The Roslindale bicyclist's widow was therefore unable even to collect an insurance settlement from the motorist.

Now, by intentionally creating a hazardous situation, the Bicycle Program has created a different target for lawsuits: the City.

Some principles for traffic operation are

  • positioning by speed between intersections,

  • positioning by destination before intersections.

Anything that contradicts these principles will result in confusion (read: accidents) and/or delays.

Bicycles usually travel more slowly than other motor vehicles, which should therefore overtake them on the left. But this is not the case when a motor vehicle stops to pick up or discharge passengers, when the right lane is blocked by a vehicle waiting to turn right or for any number of other reasons.

Motor vehicles should merge to the right curb before turning right. Bicycles should merge to the left (or else be walked in the crosswalk) when turning left or when overtaking a lane of vehicles waiting to turn right.

Some additional specific problems with the bike lane:

  • It zigzags with no transition. The block of parked cars breaks it up, .

  • The solid striped line with bicycle symbols implies that bicyclists are to keep to its right. They can't possibly do this, as the lane is too narrow for one bicycle to overtake another. The lane's width is the minimum intended for rural roads without curbs. However, bicyclists must ride farther from the edge on this urban street, which has curbs.

  • The solid line marked with bicycle symbols implicitly contradicts the traffic law which gives bicyclists every right to use the next lane when necessary and appropriate. It is an invitation for serious trouble to encourage bicyclists to overtake stopped vehicles (e.g. taxis discharging passengers) on the right. Accidents occurring under these conditions pose a liability risk.

  • While an attempt has been made to indicate that motor vehicles and bicycles must merge before intersections, this attempt is ineffective for the following reasons:

Dashes indicating the merge are short, non-standard ones which confuse motorists, and the dashed part of the lane is too short to allow a merge at normal riding speeds. This poses a liability risk!

Many bicyclists do not understand that they should not overtake a right-turning motor vehicle on its right. Even with the dashes before intersections, the bike lane adds to this confusion.

Most motorists do not understand that they should merge into the bike lane before turning right. Even with the dashes, the bike lane adds to this confusion. Now, with the bike lane, most motorists make their right turns from the lane to the left of the bike lane. Traffic is repeatedly blocked by motorists waiting for bicyclists to pass them on the right, and by bicyclists who decline to overtake a right-turning car on its right.

No laws exist in Massachusetts to define appropriate behavior of either motorists or bicyclists in a bike lane. However, even in California where such laws do exist and a question on them is in the driver's license manual, motorists don't understand them.

Suggested remedies:

  • Guide stripes without bike lane symbols, as on Broadway, are OK. Everyone understands their purpose.

  • Putting down bicycle symbols creates only confusion except on bridges and other long stretches with no cross streets and little pick-up and drop-off traffic. On other streets, dashes without bicycle symbols are a workable alternative to guide stripes. Dashes are used on Commonwealth Avenue in front of B.U. (west of the B.U. Bridge) and work fine there. The dashes reflect the reality that, while bicyclists generally ride to the right of the line and motorists drive to its left, both should and must cross the line (for example, when cars are pulling to the right to park -- there are parking spaces on Commonwealth Avenue.

  • Dashes should be standard, long passing-zone dashes which everyone understands.

  • Please, no more bike lanes inviting bicyclists to be doored. Where there is no room for a safe bike lane, either discontinue it or make the room. Bicyclists should ride no less than:

One foot to the left of a soft (poorly rideable) shoulder at the same level as the pavement

Two feet to the left of a curb, due to the hazard of pedal interference

Three feet to the left of parked cars

Read John Forester's Effective Cycling, p. 325 ff and pp. 540 ff, for a deeper discussion of bike lane problems.

The Craigie Street/Sparks Street/Brattle Street intersection: promise(s) unfulfilled

Assurances were made to me, and to other members of the Bicycle Committee, that bike lane stripes would be dashed at this intersection to reduce confusion about correct paths through the intersection.


Only the stripes on Sparks Street are dashed, with the same short, nonstandard dashes as on Mount Auburn Street. All of the bike lanes on Brattle Street carry solid lines right up to the intersection. At several corners, the bike lane is striped as a channel between solid lines to its right and left, so that motorists must cross not one but two solid lines to turn right. The outer of these lines curves into the right curb, indicating that bicyclists as well as motorists should NOT merge as close as practicable to the curb, as is the standard approach for a right turn required by law for BOTH.

West of Sparks Street, the bike lane continues into a space which is too close to parked cars, just like the one on Mount Auburn Street. I find this especially disturbing. With relatively light traffic and its single guide stripe just to the left of the relatively few parked cars, the section of Brattle Street west of Craigie Street is bicycle-friendly just as it is. The bike lane, if extended as it has been started, will encourage bicyclists to ride too close to parked cars, and closer to through motor traffic where there are no parked cars. The lane will also encourage motorists to turn right from bicyclists' left side.

Suggested Remedies

The intersection: Stripe all bike lanes through the intersection with standard traffic dashes, or else eliminate them.

Rest of Brattle Street: leave well enough alone.

Crosswalks vs. Overpasses: Anti-Car or Pro-Neighborhood?

I have long seen evidence of an anti-car rather than strictly pro-bicycle approach in Bicycle Coordinator Cara Seiderman's views. The most concrete example of this, in my opinion, is her distaste for grade-separated crossings, which she has voiced repeatedly in connection with discussions of Alewife area improvements.

I have on repeated occasions pointed out that a grade-separated crossing of Fresh Pond Parkway would provide a useful connection for bicyclists and pedestrians between West Cambridge and Fresh Pond Park. I have also pointed out that a grade-separated crossing of Alewife Brook Parkway just east of the (former, like Prince) Route 2 Rotary would provide a much more direct and safer link between the Linear Park bicycle path and the Minuteman path than the existing roundabout routes through the Alewife Station area. Every time I have brought this up, Cara has replied that she dislikes grade separations, that people don't use them, people cross the street at grade anyway, and that crosswalks are preferable because they knit neighborhoods together.

I agree with this point most of the time. But, in my opinion, Cara carries it to an unreasonable extreme. Where crosswalks were removed years ago because the volume and speed of traffic made them too hazardous; where even Boston-area residents refuse to jaywalk; where attractive parklands exist on one side of a highway and are not frequented by by the residents of the neighborhood on the other side, I am forced to ask, "isn't the idea of restoring neighborhood values by installing a new crosswalk and crossing signal a bit far-fetched?" In my opinion, the interests of motorists using the highway guarantee that a crosswalk would not be installed; but it would be impractical and unsafe even if installed.

The only purpose which crosswalks here would serve well would be anti-car -- to discourage motor travel.

Using Cara's anti-car logic (as it appears to me), we have to argue that the Fiedler Footbridge and other overpasses between Back Bay and the Esplanade should be replaced by crosswalks. Then, Storrow Drive would be an urban boulevard rather than a limited-access arterial. This would perhaps be preferable from an urban design perspective, but the improvement would be purchased at the cost of the safety of bicyclists and pedestrians, travel delays for motorists, bicyclists and pedestrians alike, and the Esplanade's reduced connection to its neighborhood because it would be accessible primarily by car and shaped to serve the needs of people who arrive there by car. This is the present situation with Fresh Pond Park and with the Charles River parklands in Watertown, Newton, and Allston, considerable parts of which have been paved over to provide parking lots for the cars which people use to reach them.

Carried to extremes, what I perceive as Cara's anti-car position results in conversion of parts of the parks into parking lots. In the Alewife area, it results in poor access for neighborhood residents and roundabout routes for through-traveling bicyclists.

The Bicycle Plan: what's cookin'?

In general: I think that the draft Bicycle Plan made a good and positive statement, but there are many technical details that need refinement. The central emphasis on bike lanes needs to be replaced by one on a broad range of improvements appropriate to the conditions at hand. In addition, some statements were poorly researched or simply off-base.

A couple of highlights of the comments I submitted to the City at the July meeting:

The section about accidents is almost exclusively about motor-vehicle-bicycle collisions, though these are only 10 to 18% of all serious bicycle accidents. There are some seriously incorrect statements about accident rates, too.

Many of the citations of laws are not from Massachusetts Law and are therefore incorrect and not applicable.

The unqualified statement that “the appropriate facilities for bicyclists are bike lanes on urban arterial and collector streets.” is a very sweeping and one-sided statement with which many cyclists strongly disagree and which does not hold water based on studies of accident rates or motorist and bicyclist behavior. I agree with the idea that "every street is a bicycle street" expressed by Cara. But this is not the same as "bike lanes wherever possible." My comments above give an idea of the problems with the bike lane approach. The flip side of the prejudice toward bike lanes is expressed in the statement in the draft Bicycle Plan that “A wide outside lane that accommodates both cyclists and motor vehicles is one way of designating a shared roadway.” But a wide outside lane is also also a way of improving a shared roadway. The error of omission is serious.

A challenge to the Bicycle Coordinator and the Traffic Department:

The first few facilities which the City constructs will be judged as a model for future facilities. People's lives, the mobility of bicyclists and the success of the City's bicycle efforts are at stake. Secondhand information is not a sufficient basis for the Bicycle Committee's evaluation of design strategies. Please be more careful about forging ahead with poorly-conceived projects which will only boomerang against us. Please explore and promote improvements which truly improve bicycling conditions. There are plenty of these to be done without getting the City's bicycle promotion efforts into trouble.

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