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
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!
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
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
Anything that contradicts these principles will result in confusion (read: accidents)
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
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
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.
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
Dashes should be standard, long passing-zone dashes which everyone
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.
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
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.