Cambridge Civic Journal Forum

May 20, 2011

Response to City officials’ comments about Concord/Follen

Robert Winters has posted a comment (#3 here) to my post about bicycling issues on the May 16 City Council agenda. Robert quotes Assistant City Manager for Community Development Brian Murphy and Traffic, Parking & Transportation Director Susan Clippinger about Follen Street and Little Concord Avenue. Their response, by way of the City Manager, is addressed to the City Council at next week’s meeting.

Their response (again, in comment #3 here) addresses some of the issues with the Follen Street/Concord Avenue installation, and reflects some progress.

Serious design issues, however, will still remain:

  • The configuration still has the same blind corners.
  • Because of the location of the curb cut into the brick plaza, bicyclists traveling away from the Common must still swerve to the right, toward approaching motor traffic, to reach the curb cut at the crosswalk on the far side of Follen Street. Bicyclists entering from the brick plaza are still close to a wall which also obscures motorists’ view of them.
  • Motorists approaching on Follen Street still won’t have a stop sign — see this Google Street View — despite the blind corners.
  • The contraflow bike lane adjacent to wrong-way parking remains.
  • There is another blind corner at the Garden Street end of the pedestrian plaza, particularly for cyclists who continue toward the Radcliffe Quadrangle on the sidewalk (and many do, though that is inadvisable).
  • The “bike box” on Concord Avenue leads to more confusion than anything else, as described here. Also, many cyclists ride east on the north sidewalk, so they can access the plaza directly, posing a risk of head-on collisions with westbound cyclists and pedestrians at the blind corner between the sidewalk and the plaza.

Contraflow bicycle travel would be safer if parking were removed from one side of Follen Street — however, the public insists on using public street space for private car storage. As a bicycling advocate and former Cambridge resident who owned a (rarely used) car and had no other place to park it than the street, I can see both sides of this issue. It is not going to go away. The people who laid out Cambridge’s streets could not foresee the deluge of private motor vehicles that would descend on the city, and had no plan either to accommodate it or to forestall it.

I do think that a very significant safety improvement could be made without removing parking, by reversing the direction of one-way motor traffic on Follen Street and Little Concord Avenue. Then cyclists headed toward the blind corner would be going in the same direction as motorists. The motorists would be going very slowly here, and cyclists could easily merge toward the center of the roadway. A curb cut into the plaza in line with the center of the roadway would avoid cyclists’ having to swerve right. This curb cut would lead cyclists traveling toward the Common to the right side of the street.

A contraflow bike lane could then be installed on the south side of Little Concord Avenue, but it would still be adjacent to wrong-way parking. I’d rather see shared-lane markings far enough from parked cars to allow a motorist to start to exit a parking space without running head-on into a cyclist or forcing that cyclist into oncoming traffic. One-way, slow streets where bicyclists are allowed to travel contraflow are common in Germany, without bike lanes, and research has demonstrated their safety.

As to Murphy’s and Clippinger’s comments:

Motor vehicle volumes on the street are very low and most drivers are ones who live there and use the street regularly. The contraflow lane was installed to improve safety for cyclists by creating a dedicated facility for them to ride in and through the presence of pavement markings to remind motorists that bicyclists are traveling there.

The low motor-vehicle volume argument is an example of what I call “bean counter” safety analysis. I have heard the same argument before from Cara Seiderman, in connection with the wrong-way contraflow lane on Scott Street. This approach offers cyclists and motorists only statistical comfort, leaving them defenseless against actually preventing a crash through their own actions — as in “well, I can’t see over the SUV parked in front of my car, but probably no cyclist is coming so I’ll pull out.”

The bike lane does serve as a buffer to help prevent collisions between cars and other cars, but it doesn’t pass the test of preventing collisions between cars and cyclists. The comforting words “dedicated facility” don’t actually describe how it works in practice. Reminding motorists that bicyclists are traveling in the bike lane doesn’t count for much if the motorists can’t see the bicyclists.

Clippinger describes a safety analysis which looked at generalities about traffic volume. The claim that the dedicated facility was installed to improve safety may describe intention, but it does not describe either the design, or the outcome. This is a crash hotspot, remember. I have described design issues, and some solutions that look rather obvious to me. The city, as usual, installed a boilerplate bike lane design without much insight into whether it actually would be functional and safe.

May 16, 2011

About bicycling issues on City Council agenda tonight, May 16, 2011

A cyclist and a motorist approach the blind corner at Concord Avenue and Follen Street

A motorist cuts off a cyclist at the blind corner of Concord Avenue and Follen Street

The city's own picture of this scene shows a cyclist happily steering straight toward a curb.

A picture of the same scene from the City's Web site shows a cyclist happily steering straight toward a curb, which is cropped out of the picture.

Looking from the opposite direction, this is the path a bicyclist must take, swerving toward traffic to reach the curb cut.

Looking from the opposite direction, this multiple-exposure photo shows the path a bicyclist must take, swerving toward Follen Street traffic to reach the curb cut at the crosswalk.

This post attempts to shed some light on agenda items on tonight’s City Council agenda.

The quoted sections are from another commenter. I’m not sure I know how to reach him, and time is pressing. I don’t know whether I have permission to use his name, so I won’t. The unindented paragraphs  are my own. We’ll start with the other person who commented.

Two of the three items on the city council agenda are interesting examples of problems related to bicycle infrastructure that has been implemented over the past several years.  The third is simply a request to fill potholes, but includes an ignorant comment about bicycles needing to ride near the curb (not true according to Massachusetts law or Cambridge ordinance).

That is agenda item O-7 on the page linked here

The first bicycle facility problem is a contra-flow lane through a blind corner where motorists have no expectation that there will be contra-flow traffic of any sort as they round the corner on a one-way street.

That is agenda item O-3 on the page linked here.

The street view is looking south on Follen Street as it intersects (Little) Concord Avenue.  The bike lane crosses in a contraflow manner from left to right, and then continues across the small brick plaza to the right to join with Garden Street and the continuation of Concord Avenue.  The intersection just beyond the plaza is the same one where Cambridge has installed a bike box critiqued by John Allen


The contraflow bike lane is adjacent to wrong-way parking, another odd feature of this installation — see this for a description and explanation of wrong-way parking:

Upon reaching the corner, bicyclists have to ride out past a stop bar and stop sign before they can see around the corner. A stop sign requires two actions, a stop and a yield. The yield is what actually prevents a collision — but it is only possible where you can see conflicting traffic.

Many if not most of the bicyclists approaching this intersection are Harvard students headed up to the Radcliffe quadrangle. Are we to assume that they aren’t bright enough to figure out that they must yield? The problem is that nobody ever instructed them, and many have little bicycling experience as they suddenly find themselves dependent on a bicycle for transportation. Also, the stop bar isn’t where there’s anything to yield to unless a pedestrian happens to be crossing — it encourages running the stop sign, sort of like traffic ju-jitsu: aha– fooled ya!.

See Google Street View looking toward the stop sign:

I have a discussion of this contraflow bike lane in the page linked below this paragraph. The third photo down the page shows the stop sign. I prepared the page linked below years ago, shortly after the installation. This was clearly going to be a problem location.

The curb ramp on the far side of the intersection is located at the end of the crosswalk rather than in line with the bike lane. Bicyclists must ride toward approaching traffic to reach the ramp.

Bicyclists coming in the opposite direction off the little pedestrian plaza are hidden by a wall and subject to similar risks. This entire treatment is a prime example of Cambridge’s principle of Design by Wishful Thinking.

The second problem is at a rather unremarkable intersection, so it is not clear to me why there would be issues.

See Council Order O-19 on the page linked here.

The street view is looking south on Ellery Street as it approaches Broadway.  Ellery is a narrow one-way street with a bike lane.  Traffic is typically slow, but can be heavy at rush hour.  Broadway is a two-way narrow connecting through street with parking and no bicycle infrastructure in this area.  Traffic typically runs about 25-30mph, slower and heavier at rush hour.  The intersection is also at the corner of a local public high school campus.  Neither street is difficult to cycle on if you have at least modest traffic experience.

There is a flashing yellow and red overhead signal indicating a stop sign for Ellery Street entering from the north.  I tried to find data related to the several accidents cited, but did not see anything apparent on the Cambridge city web site.  I can speculate that most of the car/bike accidents are probably due to scofflaw behavior — either bicyclists in the Ellery bike lane not heeding the stop sign as they continue across Broadway, or wrong-way riders in the Ellery Street bike lane illegally approaching Broadway from the south.  Also likely would be standard right hook, left cross, and failure to yield collisions caused by motorists, but I don’t see why those would be any worse at this intersection.

I see a double-whammy right-hook provocation for bicyclists headed south on Ellery Street, in that the bike lane on the far side of the intersection is to the left of parking (and in the door zone, as is usual in Cambridge), while the bike lane on the near side is at the curb and carried all the way up to the intersection. So, bicyclists are encouraged to overtake motorists on the right, then merge left inside the intersection where motorists turn right.  I think that the high traffic volume and prevalence of high-school students probably also account for the number of crashes. There probably are scofflaw crashes too. Yes, it would be very interesting to see details so as to get a handle on what is actually happening here.

I’m not looking for any answers, but I thought people on this list might be interested in what Cambridge lawmakers are thinking.

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