Friday, February 19, 2010

Rethinking Coolidge Corner Lane Scheme

I have some serious concerns about the latest Transportation Board proposal for lane changes at the Harvard/Beacon intersection at Coolidge Corner.

The most recently proposed plan, to reduce the number of southbound Harvard Street lanes to one on the north side of Beacon St., remove the median on this same side of the intersection and add an additional northbound lane,  has come about as a result of focusing entirely on trying to solve the problem of gridlock or “blocking” that occurs regularly at this intersection. While this is a serious problem, I do not think the proposed solution will be effective, nor does it address the most prominent contributing factor. However, in addition to these shortcomings, I fear we have overlooked some of the serious negative consequences likely to result from this narrowly focused attempt to “fix the problem”.

We can surely all agree that there is a heavy volume of vehicle traffic flowing North on Harvard St. Beyond this point, I fear there are as many opinions as there are individuals. My professional experience leads me to the conclusion that there are two principle reasons why the traffic fails to clear the intersection before the green signal activates (and then frustrates) the westbound Beacon St. flows. Number one is the simple fact that two lanes of traffic must merge into one. Allowing a bit more space for this to occur by having an additional lane accepting traffic on the far side of the intersection will not sufficiently accommodate the merging traffic. To complicate things, your proposal retains curbside parking here. While I support maintaining the parking for its traffic calming and pedestrian buffer functions, the “friction” caused by parking vehicles and the inevitable double parkers will minimize the effectiveness of the scheme you are proposing if your goal was to maximize traffic flow through this bottle neck.

A much more effective solution would be to eliminate the two to one lane merge all together by making the northbound right hand lane on the south side of Harvard for right turns and buses only. That way only one through lane would be crossing Beacon St. to begin with. Yes, this will extend queue’s on Harvard St. A don’t block the box treatment and enforcement would be necessary at Longwood. Otherwise, there is sufficient storage capacity for the resulting queue. Yes, traffic will back up on Harvard, it already does, but the “flow” will be regulated before it enters the intersection at Beacon and the problem will be eliminated.

Another contributing factor to the gridlock problem relates to the width of Beacon St. It appears that the signal timing does not adequately compensate for this. It appears that some vehicles entering the intersection on the yellow (and sometimes red) do not have adequate time to travel the full distance to clear the intersection, regardless of or made worse by the delay at the merge. If the clearance time were lengthened, that is if the signal on Beacon St. simply stayed red longer, drivers would be spared the frustration.

Even if, after considering my comments you still believe the proposed changes will work for the limited goal of moving more vehicles through this very small segment of our roadway network, I ask that we take a moment to stand back and ask ourselves what our overall goal should be and what the wider consequences from this change may be.

Coolidge Corner is, for many a vital transportation and commercial hub. Thousands of commuters from the T stream through daily, stopping at shops and restaurants on their way. Thousands more visit daily from home on foot. It is for their comfort and safety that I object to this scheme. The median in the middle of Harvard Street is a vital refuge for many a pedestrian, especially those who have difficulty speedily crossing in front of impatient drivers. I think it should be extended rather than eliminated. Consider also the effect of combining the through and right turn lane in the southbound direction. Who hasn’t been walking across the street, only to hear the car behind the car waiting for you lay on its horn? The volume of pedestrians is heavy at this intersection. We should be really glad for the high pedestrian volume because if each one those people were in a car, they would be taking up 60 times more space than they do on foot, none of us would be going anywhere.

Because of the heavy volume of pedestrians, right turning vehicles will sometimes wait a long time before they can turn, thus blocking the through travel. How patient will those drivers be after waiting through a light or two? How safe, comfortable or relaxed will the pedestrian crossing the street in front of those drivers be?

Already, the automobile is favored over the pedestrian at this intersection. There is no protected pedestrian phase, despite the heavy pedestrian volume. Many times car drivers play dodgem trying to turn through a group of pedestrians. All of this is particularly menacing for elderly or disabled people. Most people have no idea that they must press the very distant button (which is often blocked by snow mounds) to get a walk signal. They either wait and wait, or finally give up and go. This is especially problematic for parents with young children who are trying to teach their kids how to cross safely using the signal. If we make it more difficult and dangerous and unpleasant to walk, which I think this scheme does, we are “shooting ourselves in the foot” in terms of mitigating congestion or maximizing the capacity of our infrastructure, as walkers will take to cars because they no longer feel safe. Infrastructure is a precursor to activity. Make room for more cars and you get more cars. Make it more pleasant to walk and more people will walk. It is that simple. Make Coolidge Corner more people friendly and you get more people.

Paying attention to and giving greater accommodation to those on foot focuses our attention on the human scale and impacts the quality of everyone’s experience in Coolidge Corner. We have a choice. Can we find a balance between accommodating the through traffic and making Coolidge Corner a people place? I hope so.


A walker from Somerville said...

Have they fixed the pedestrian signals at this intersection and others yet?

Before the intersection was redone, there were countdown signals that automatically said walk with each light cycle, and always gave people enough time to fully cross Beacon St. They were replaced with non-countdown signals that require pedestrians to push a button (including a second button in the Beacon st median!!!), and many cases do not leave enough time for pedestrians to fully cross Beacon St without waiting through an entire other phase.

With the high number of pedestrians, the fact that the pedestrian signals all up and down Beacon Street were actually made WORSE for pedestrians is a complete outrage, particularly for the amount of money that was spent on this project. The fact that they've remained so poorly configured after the project is long complete is even more insulting.

Pamela Rosenthal said...

This is a great post. Thank you putting it together. I think you’re right on track.

I think you have some very sound suggestions that should be tried out before we go to the expense of changing the lanes and removing the median from Harvard St. One suggestion should be tried before all others: extending the length of the red signal to allow the northbound Harvard St. drivers to finish crossing Beacon.

Another potential tweak is to properly synchronize and time the lights at Babcock St. Even if two lanes are introduced on Harvard northbound, these cars will still get stuck at Babcock or even further down at subsequent lights if the light patterns are not addressed first.

I would also be worried that having two dedicated lanes would result in increase driving speeds, which could become a potential hazard for people who are trying to cross at the cross walk a little further down the street near the corner of Green St as well as for people trying to park.

I agree that it seems like it would be better to funnel the cars into one lane on the south side of Harvard before the Beacon Intersection rather than try to do this on the north side where the street seems narrower in general and the concentration of cars, businesses and people is higher.

I also think the situation could be improved by changing the pedestrian traffic signals or even combining the pedestrian crossings for both directions into one crossing which would allow people to cross diagonally as well. That way, when the vehicles had the light, they would be able to pass freely without having to negotiate the pedestrians. This is especially a problem with westbound Beacon St. traffic trying to turn right onto Harvard.

Gina said...

Excellent explanation. Thank you.

Gina said...

Excellent explanation. Thank you.