phi (totient) wrote,

prepared remarks

First, some background. A quick Google News search suggests that Beacon Street in Somerville has been paved exactly twice in its entire history: once in 1925 and again in 1957. Streets like this need to be repaved every 20 years and when I arrived in Boston in 1988 Beacon was already in desperate need. The city did trick Level 3 Communications into repaving about 1/4 of the surface as part of a fiber laying operation around the turn of the century but even this portion of the street is beginning to fall into disrepair.

Residents have been pushing for a reconstruction project for at least 20 years and perhaps longer. For a time the promise was that this project would also eliminate the utility poles lining both sides of the street, relocating the power and telecom lines underground as Cambridge did when it resurfaced the continuation in the late 1990s. Repaving the street will cost something like $5 million. Relocating the utilities would be $10 million. Various smaller improvements to the streetscape might come to another $1 million or so. The city would, naturally, prefer for the state and federal governments to pick up the tab, and they appear to be willing to do so, to the tune of $6 million or so, as part of an "improvement". I don't really understand what kinds of features have to be included for this project to qualify but other such externally funded projects recently have included Somerville Ave (which added bike lanes) and Magoun Square (which did not).

You will notice that the $6 million on offer does not begin to cover relocating utility lines. Beacon St and its right of way are pretty narrow and the 1957 repaving already widened the roadway as much as possible, pushing the curbs right up to the poles. There is lots of bike traffic and only parts of the street are wide enough to support even substandard-width bike lanes. So the city has come up with a proposal to eliminate parking on one side of the street for about 1/3 of the length of the street, and use the 7 feet of space gained to replace our 4-foot bike lanes with cycle tracks, 6 feet wide on the no-parking side and 9 feet wide on the other (to allow for a door zone). Naturally the residents are furious at the prospect of losing over 100 parking spaces, and with good reason. Given that off street parking spaces rent for $90/mo the present value of all of the parking on the street is about $12 million and removing part of it puts the cost on the residents and business owners. But it's worse than that: Beacon has very few parking alternatives as the side streets on one side are mostly private ways and the other side is the Cambridge line so residents can't park there either. Restricting parking to one side means that when the other side has a street sweeping day there is simply nowhere to put hundreds of cars. And that's not even addressing the issue of handicap parking on the wrong side of a busy street with no crosswalks and no good way to put in crosswalks once cycle tracks are in place.

Some might say that making life harder for drivers is worth it if it made life better for the cyclists, but it doesn't even do that. Cycle tracks swap the parking lane and the riding lane, which can be better for some cyclists in some situations but is not appropriate here. The reasons why not are a little nuanced and I'll get to that in a bit.

Pedestrian advocates are generally against cycle tracks and one of them spoke eloquently at a preliminary meeting last week, suggesting that narrowing the sidewalks from 10 feet to 7 would be better than effectively sharing space with 300 high speed cyclists per hour. This would save parking and allow safe bike lanes with buffer zones on either side. The city says they can't do that because of the utility poles. But some residents looking to preserve parking have pointed out that that's only true if you make the curb a straight line. Good traffic design already suggests that curbs should not be straight lines but instead should curve toward the street for 20 feet on either side of an intersection or 10 feet on either side of a hydrant -- anywhere that cars aren't allowed to park. Many utility poles are in such bump-out locations already, so that they can feed utilities down side streets. A few more bump-outs could be created without costing parking, for example in locations where driveways are separated by 1.5 car lengths and the pole is not centered in the space. Remaining utility poles could be relocated or cost a parking space depending on the relative difficulty (and expense) of moving that particular pole and the level of pressure on (and implicitly, cost of) parking spots at that particular point along the street.

Last night was the DOT hearing for the Beacon Street Reconstruction Project. I strongly prefer the alternate proposal but from a cyclists' and overall safety perspective rather than because of the parking. Pat Jehlen encouraged me to prepare some remarks not just because she is also primarily concerned with safety but also because she wants to blow a hole in the cyclists-vs-nimbys narrative.

I got there good and early and sat in a spot that would ensure I could speak at the beginning. We were asked to limit ourselves to 2-3 minutes and the first speaker rambled on about parking for 5 minutes, never really touching on any of the specific problems with the city's proposal. I went next and also took 5 minutes to give all of my remarks, knowing that I was going over but also knowing that there had not been an admonishment to the speakers on time and also that such an admonishment coming after my speech would help the points I was making rather than hurting them (other cogent speakers who went over time were cheered for doing so). Speaking before any of the other cyclists seemed to take the wind out of a lot of "cycle tracks are good so this cycle track is good" speeches, and generally I feel like I set the tone by focusing on safety. I hope it works.

I had to leave after about an hour of comment and there was still quite a line, though some people had had time to get through it twice. As I was leaving several people asked me for copies of the speech, for more information (I had some studies with me), or for my email address. I also made sure that the project folks and the reporter from the Somerville Journal had copies of my remarks. You all should have them too, so here they are.

Are cycle tracks safe?

The literature on this appears to be mixed.  Proponents and detractors can easily cherry pick studies that show that cycle tracks are safe or unsafe.  They can also easily cherry pick studies with flawed methodology showing their opponent’s point of view and claim that this means that their opponents’ claims are invalid.  Even within a single study outcomes are often varied from one cycle track to another.

Does this mean cycle track studies are useless?  No.  Generally, studies of the same cycle track or group of cycle tracks are consistent.  Montreal cycle tracks are safer than Berlin cycle tracks.  Within Montreal, cycle tracks on one way streets are three to four times safer than ones on two way streets.  And overall, correcting for obviously flawed studies, more studied cycle tracks are safe than unsafe.  Like any transportation infrastructure, safety of cycle tracks depends on their design and their suitability for their environment.

Only a few studies have attempted to discern the safety impact of design features of different cycle tracks.  And unfortunately the study which best measures the safety impact of cycle track design uses a flawed statistical model in an attempt to claim that all cycle tracks are unsafe.  The city’s Design Exception Report corrects these statistics to show that this is not so; the raw data show that many designs of cycle track are in fact safe.

But two particular design features that this study identifies still make a difference to cycle track safety.  The first of these design features is the presence of turn lanes.  Drivers leaving the main road on a path that will cross the cycle track often do not expect or cannot easily see bicycles on the cycle track.  Drivers also often expect cyclists to the right of parked cars to be moving at pedestrian speeds, and miscalculate whether they have time to make a turn.  This is shown by the number of collisions blamed on “excessive speed” on the part of a cyclist going 10 to 12 miles per hour.  Cyclists in Boston know to look out for turning traffic, but here in Somerville many motorists do not use their turn signals.  Having a dedicated turn lane helps cyclists identify turning motorists and avoid accidents, even when the cyclist has the right of way.

The other design feature is a cycle track that reenters the roadway before intersections.  Motorists turning off the main roadway have better visibility of cyclists, more correct understanding of the cyclists’ speeds, and for right turning traffic a greater distance to get to the right of bicycle traffic so that the path crossing is not constrained to a particular point in space and therefore time.  This is called a “shortened” cycle track, as opposed to an “advanced” cycle track which runs right up to the intersection.

Even applying the city’s statistical corrections, the Copenhagen data show that to be safe, a cycle track must have at least one of these two features.

Not identified by this study but easily discernible in the raw data from other studies is that the safety of a cycle track depends on the number of driveways that cross the cycle track to enter the roadway.  

Cycle tracks in Cambridge are all shortened, and located on roads with few driveways or intersections.  The Vassar Street cycle tracks leave the roadway 200 feet after each intersection and reenter the roadway 300 feet before the next intersection.  Vassar Street also features left turn lanes at Massachusetts Avenue.  This is a shining example of how to build a cycle track.

Examining the streets of Montreal and Berlin supports this conclusion.  Neither city uses shortened cycle tracks, but Montreal generally has turn lanes, especially on one way streets where it is easier to find room for them, while Berlin does not.

There is no room on Beacon Street for turn lanes, so to make a cycle track safe would require using a shortened cycle track.  But the intersections on Beacon Street are generally less than 500 feet apart.  Even allowing for advanced cycle tracks at intersections where traffic flows only toward Beacon St, a safe design would result in no cycle track at all in the outbound direction.  The only part of Beacon Street that is safe for a cycle track is a 1500 foot section inbound between Museum St and Washington St.

A cycle track in some other location in Somerville could be safe.  For instance, Washington St between Union Square and Sullivan Square is wide enough to support turn lanes, and even without turn lanes it has few enough cross streets into which traffic can turn to permit a safely constructed cycle track.  With the expected construction of Green Line, this would connect three MBTA stops and transform a route currently cycled only by the brave into something everyone could use.  But a cycle track on Beacon St would not be safe for anyone.

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