Committee Sends Plans to Selectmen

Summary of the decision: The expanded 18-member committee overseeing the redesign of Mass. Ave. in East Arlington last night (June 24) voted to submit a basic design to the Board of Selectmen.

The plan features two eastbound lanes, one-and-a-half westbound lanes, dedicated bicycle lanes, and traffic signals at all existing locations and at Bates Road.

If the Selectmen submit this plan to Mass. Highway on behalf of the town, and the state highway agency approves it, this design will be the framework within which other design issues are worked out.

Meeting Notes: (to the best of my ability, and completely unofficial. My personal comments are in red.)

The meeting began with a presentation from John Michalak and Doug Prentiss, consultants retained by the town for this project, recapping their work and explaining their requirements, methods, and some of their conclusions. This was for the benefit of those of us recently appointed to the panel, the second of two meetings at which we newcomers essentially dominated the agenda with questions and comments. The main points follow after the break.

1) Design of Mass. Ave is guided and constrained by state and federal requirements and documents. To meet these requirements the consultants have gathered detailed information about the road, traffic signals, and the motor, pedestrian, and bicycle traffic flows. This information is reported in the draft functional design report that is posted on the Town web site.

The consultants did an impressive job with this presentation that, among other things, was a primer on how to read the functional design report. They walked us through many of the technical tables, described some findings and data-gathering methods, and even showed us some of the forms they had to fill out so that we would understand what the work comprised.

2) The May traffic counts strongly corroborate the original October counts, except for a dramatic increase in bicycle traffic. There is a sharp eastbound peak in traffic during the morning commute. The evening peaks both ways are less dramatic because they returning traffic is spread out over time. The consultants were ridiculed for their data-collection methods at at least one public meeting, but this second (and longer) data set vindicates the original in my view.

3) The consultants expect traffic counts in December to be slightly less, based on actual traffic data for Routes 2 and 93 in December.

4) The report includes a required review of traffic accidents during the past three years. There were no fatalities during that period. The worst location for accidents was not at a specific intersection, but along Mass. Ave. between Lake and Thorndike St.

The state has a crash-rate requirement that is a measure of accident frequency and severity per location. The intersection with Route 16 exceeds — is worse than — that requirement, and the Lake St. intersection comes close to it.

5 ) The consultants also assessed intersections for traffic-signal warrants, which are characteristics the State requires before it will fund a signal. The existing lights at Teel-Thorndike and Linwood-Foster do not satisfy enough of these warrants (including, for instance, enough traffic to warrant a light), but Bates does. This has been very controversial, as residents at or near those intersections seem to prefer the status quo in all cases. But the source of this requirement lies with the State, not the town, and although the Town may request a waiver the State is not obliged to honor that request.

Again following state guidelines, the consultants assessed all the intersections for level of service. Bates Rd. gets an “F” at peak based on wait time to make a turn onto Mass. Ave. Signalizing the intersection correctly would achieve a “C” (peak waits of between 20 and 35 seconds).  I have simplified this summary greatly, but if you want to know more it’s on Page 12 of the functional design report.

6) We viewed some visual simulations from Synchro, a modeling tool that expresses traffic data graphically. John Michelak told the committee that Synchro is just a tool and that it does not depict how individual drivers actually behave.

I was very glad he made this point. Some in town have criticized the consultants for relying on models that are plainly wrong. For example, the Synchro simulation of traffic at Bates Rd. that we saw showed drivers waiting patiently behind the legal stop line at Bates until they could turn onto Mass. Ave. In reality drivers inch forward into traffic especially to make left turns.

This criticism is really off-base. The consultants described actual behaviors at Bates Rd. and elsewhere perfectly clearly. In fact, that behavior is already captured by the data that Synchro depicts, even though Synchro neatens things up in the display. All the simulation provides is a graphical depiction of the actual data collected (and in the case of future estimates, extrapolated).

It’s useful especially for those of us who have trouble visualizing data from a table of numbers. The numbers, however, include all the behaviors even if the display does not show them.

7) The consultants project traffic flows in ten years by assuming a simple growth rate of 1% per year. This is greater than the historical data to provide a cushion. Doug Prentiss noted that there are no new development projects likely on the corridor and therefore “what you’ll have is what you’ve got.”

Using these future estimates, they project that the delay at Bates Road would grow to more than 126 seconds from Marion (in the PM peak, nearly 110 seconds in the morning) if there is no signal. With a signal, this would fall to 21 and 46 seconds, respectively.

8) The numbers show that it is the intersections, and not lack of capacity, that are the clog points on Mass. Ave, the consultants said. Under the proposed configuration, traffic would not stop flowing on Mass. Ave. and consequently there would be not increase in cut-though traffic. This is what they said, but I think it would have been more accurate to say that traffic won’t stop any more than it does already. That’s because today’s traffic jams are not caused by lack of capacity — there’s actually a lot of it — but because of other problems, such as a traffic jam on Route 16. I’m sort of nitpicking here — their basic point was that traffic will continue to flow as well as it does even with fewer lanes and a 1% per year growth in traffic volume.

9) In response to questions, the consultants said the following.

  • Bump-outs (projections from the sidewalk at pedestrian crossings) can speed motor-vehicle traffic flow by reducing the walk-light part of the traffic cycle.
  • Proposed bump-outs are only at crossings (and not at every one); the number of legal parking spaces won’t change.

10) In response to a question, committee members explained why they had modified the original proposal to add a full lane eastbound from Lake to near Boulevard Rd. (The first plan had one through lane and left-turn lanes.)

The initial concern was to “store” the queue of cars that sometimes forms at the light at Route 16. To respond to this, the committee looked at beginning the double-lane at Thorndike St.

Then the committee felt that having a “one-and-a-half-lane” configuration from Chandler to Thorndike would be confusing to drivers. Consequently, they asked the consultants to prepare a plan with two lanes eastbond essentially all the way. (This is reflected in the June 16 drawings.)

I asked this question because (1) I’m concerned that we are leaving real pedestrian-safety benefits on the table for dubious reasons and (2) I wanted to hear from the veteran committee members, who had mostly been silent. I’m not sure that either argument convinces me, but the answers I heard were thoughtful and told me some things I didn’t know or hadn’t considered.

Given that the consultants told us that there would be no impact on actually trip time by adopting the “one-and-a-half”-lane plan, I am particularly skeptical about the value of “storage.” If you have two lanes instead of one, it will store twice as many cars, but so what? The queue is just as long, it’s just doubled over, and it doesn’t get you to work any faster. On the other side no one seems to doubt the pedestrian-safety benefits of the original configuration.

There was some more general discussion, and then several members asked if the Committee could vote to submit the plans to the Selectmen. The motion passed 12 to 4, with 1 abstention, so now the ball is in the Selectmen’s court.

This was a roll-call vote so the curious can check at Town Hall, but I didn’t record it (this is unofficial, remember?) Thanks for reading.

I was the abstention. It was clear to me that the committee was ready to vote, and had done a lot of work, but I remain concerned that we were too quick to drop the pedestrian-safety benefits of the original plan in favor of “storage.”

Despite that I think there’s a lot to like about this plan and the committee deserves praise — the original committee that did all the work, not me — for its attention to many many difficult technical issues.

Advertisements

4 comments so far

  1. Michael Ruderman on

    Adam,thank you for an excellent summary. You do us a great service.

    Maybe I can clarify something about the utility of a double-lane queue. One of the big problems with storage lanes (the lanes where cars wait before making a “move”, which is trans-speak for intersection left or right turns)is when to get into them. A driver unfamiliar with the intersection won’t get over in time, and ends up being stuck. The same goes for a driver who’s simply not paying attention, or trying to jump the queue at the very last moment. We all know how rash road behaviors become around here over changing lanes. Aberant or unexpected operator actions cause the modeled outcome (as you rightly observed with the Bates/Mass. Ave. moves above)to “crash”, in all senses of the word.

    Doubled storage lanes put that “decision point” for the operator to get over closer to the intersection. You have more time to decide, and a big visual clue in the looming appearance of the intersection itself to remind you to do it.

    Again, thank you very much for the meeting notes.

    • Adam Auster on

      Michael, you are welcome. I’m no traffic expert. My only excuse for being on the committee at all is to improve public participation. This is my way of fulfilling that role.

      If I understand your explanation correctly, you are saying that double-storage lanes give drivers useful cues about where to be as they approach the Alewife intersection.

      The original plan had this–double lanes beginning around Boulevard Rd. (Older versions of the plan are online here.). There was an intermediate version that had double-lane-storage beginning at Thorndike.

      How much is enough? It seems to me that starting the double-lane storage after Fairmont St. is plenty.

      What we lost were safer pedestrian crossings between Lake and Thorndike. This is the stretch of Mass. Ave. that, I learned Wednesday night, has the most accidents

      Also, it seems to me that if there is the potential for confusion about when to get over a lane or two at Alewife, it is aggravated, not relieved, by having a double lane all the way from Lake St. (When is the best time to get into the left lane? I’ve lived here 14 years and still don’t know.)

      Please feel free to set me straight! And thanks.

  2. Phil Goff on

    Adam – the reason I supported (well…”did not oppose” is probably more accurate) the two-lane configuration east bound was because the additional storage space that it will provide does bring some benefits other than just “storage for storage sake”. I was fearful that a queue of cars extending more than 3 or 4 blocks beyond Rt 16 (as it does today) would make it extremely difficult for residents to access Mass Ave via a left turn from many side streets. I also feared that with one lane, buses would take longer to reach each individual bus stop on the south side of the street. Providing two lanes would allow buses smoother access to all stops except maybe the one at Boulevard road. Finally, I’m less concerned with the notion of two lanes in one direction and more concerned that the plan includes a median zone (flush or otherwise) that could be extruded at strategic locations to provide a pedestrian refuge island at unsignalized crosswalks. While currently these refuges islands are not in the plan, I hope the larger committee will discuss them more thoroughly at a later date.

    • Adam Auster on

      Phil, thank you for this explanation. (Phil is one of the eight original members of the Mass. Ave. Review Committee, and they deserve our attention and our thanks.)

      I have heard some of these ideas before, though not articulated so well. Without wanting to be argumentative, my concern is that the benefits you describe are less certain than the pedestrian-safety benefits we are giving up.

      Consider the question of how a longer queue would affect cars entering Mass. Ave. from side streets.

      (As I recall, Annie LaCourt asked John Michalak a question about this back in May, and did not get a definite answer.)

      It may be that for some cars at some locations, a stack of cars queuing along Mass. Ave. will mean longer waits for an opening, especially to make a right turn. But it may also make such turns safer, by slowing traffic, and that is likely easier for many drivers.

      I can also say from experience that if I’m turning left onto Mass. Ave the answer is less clear. Probably I’d prefer the side of the street that I am crossing to have only one lane (and probably the side I am turning onto to have two).

      My point is that from the point of view of entering traffic, there are costs as well as benefits to two lanes, which differ by trip and by driver, and the net result of two lanes is not clear.

      By contrast, the pedestrian-safety benefits of the one-and-a-half-lane configuration are not ambiguous. Everyone seems to agree that this plan would (a) slow cars down, (b) shorten the distance that pedestrian must cross against traffic, and (c) end all collisions with pedestrians who are not visible from one of the lanes.

      Furthermore, everyone seems to agree that (a), (b), and (c) would materially improve pedestrian safety, specicially fewer and less-severe accidents involving pedestrians and cars.

      In a nutshell: swapping pedestrian-safety benefits that are certain for traffic-flow benefits that are not does not seem to me to be a good exchange.

      I hope you are right that this ultimately will not matter very much.


What do you think?

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: