Understanding the New Bus Lanes

See prior posts in this thread for additional background.

Thousands of commuters on Mount Auburn Street and on Fresh Pond Parkway had a very rough ten days starting on Monday, November 5. That is the day that a contractor swapped in a new controller for the traffic signals and failed to properly program it.

The new Siemens 60 signal controller is so sophisticated that only a few engineers have the expertise to properly program it. Commuters endured ten days of bad timing until the right specialist was able to get it working as intended.

As of Thursday, November 15, DCR engineers believe that the signals should continue to run reliably (until natural disaster strikes or humans again intervene).

With the lights working properly, we can now assess the operations of the new bus lanes along Belmont and Mount Auburn Streets near Mount Auburn Cemetery. For the last ten days, motorists have understandably been blaming the bus lanes for the delays, but I hope motorists will take another look now that the signal timing has been corrected.

The analysts who modeled the bus lanes before implementation believe that they will help buses without degrading the experience of motorists for two reasons.

First, much of Mount Auburn Street east bound between Belmont Street and Fresh Pond Parkway was almost a single lane already. There are four left turns for cars going east in that stretch — into Star Market and at Homer, Aberdeen and Brattle. At rush hour, there are frequently cars waiting to turn left and through-traffic has to weave around them. So, the effective capacity of the stretch for automobiles was already not so much more than that of a single lane. The intermittent bus lane preserves much of that capacity.

Second, Cambridge and DCR have made important changes in how the traffic signals operate. The light at Coolidge Avenue has historically given 43 seconds of green time to inbound motorists on Mount Auburn at rush hour. However, the immediately following light at the big Fresh Pond intersection offered only 31 seconds to those motorists. That Fresh Pond light has been the real limit on throughput.

To protect Mount Auburn drivers while adding the bus lane, DCR has boosted the time allocated to Mount Auburn Street at Fresh Pond from 31 seconds to 43 seconds, enough to make a big difference in the throughput on Mount Auburn Street. Additionally, Cambridge has improved coordination at the other lights on Mount Auburn so that traffic in both directions should flow more smoothly.

Green time at an intersection is a zero sum game: The traffic on Fresh Pond Parkway loses 12 seconds of green time in the changes, going from 58 to 46 seconds at the crossing of Mount Auburn Street. However, that traffic already had only 46 seconds to cross Brattle Street, so the throughput across those combined intersections should remain roughly the same.

That’s the basic give and take in the morning rush hour on weekdays. Buses filled with people standing up should now be able to move through much more quickly. Drivers on both Mount Auburn and Fresh Pond Parkway should see very limited changes in their actual end-to-end travel time.

I very much hope that motorists who experience unreasonable delays near these intersections will continue to let me know so that I can provide feedback to the engineers. My cell is 617-771-8274 and my email is william.brownsberger@masenate.gov. Commuters can also always comment publicly at willbrownsberger.com.

Coming in our next construction season is a set of further changes for the Fresh Pond intersection that should improve both safety and throughput. More on that in future posts.

Tegin Teich who has led communications regarding the project for Cambridge issued the following statement on November 16:

Cambridge and DCR staff worked together this week to make extensive observations and fix the signal timing and coordination issues that we were facing last week and beginning of this week. We believe that as of Thursday (yesterday), signal timing and coordination on Mt. Auburn at Coolidge Ave and Fresh Pond Parkway has been corrected and is functioning as intended. We hope this is mitigating the frustrations that I’ve heard from many of you in the last few weeks. If you are still experiencing problems due to the current signal timing, we appreciate your comments and feedback.

Staff will be monitoring conditions over the holiday week next week, although we know it will be an atypical week.

The next step after the holiday week will be to evaluate the Mt. Auburn Bus Priority Pilot project. As has been shared with the public, we expect two phases of evaluation. In the first month or so we will observe, survey, and do preliminary measures of private vehicle and bus travel times. In the spring, we will be carrying out a more thorough data collection effort and complete our evaluation.

When signals are working as intended, we believe that the bus priority pilot will result in significant benefit for the majority of roadway users in the peak travel times, the bus riders, as well as have a low impact on drivers. Despite the signal timing challenges at Coolidge and Fresh Pond Parkway, early observations indicate that the changes made in the outbound direction – modifications to the Brattle intersection, installation of bicycle lanes, changes in signal timing at Aberdeen and Belmont, installation of transit signal priority at Aberdeen and Homer for the buses, and installation of the red lane queue jump in the curbside lane at the Belmont/Mt. Auburn St intersection, which continues into the bus lanes on Mt. Auburn Street in Watertown – has already benefitted all users on Mt. Auburn Street in that outbound direction. We will, however, collect data and measure these effects for both directions.

Published by Will Brownsberger

Will Brownsberger is State Senator from the Second Suffolk and Middlesex District.

28 replies on “Understanding the New Bus Lanes”

  1. Bit of a digression, but why do you say the left into the Star is illegal?
    I don’t see a sign, and the regs say:
    Do not cross a double yellow line unless turning left.

  2. My only concern is that Cambridge does not seem to have the necessary talent, skill level, or experience to maintain these tricky light switches. And with the above wording such as WE BELIEVE bus priority will benefit everybody, WE HOPE this fixes the problems. I would prefer some level of confidence that the problems have been resolved.

    1. From a professional engineering perspective, planners have an opinion that the changes will work. But, real world conditions are more dynamic than any model so I use cautious phrasing when I report their conclusions.

  3. Thank you, Will, for a lucid and thorough explanation of the project. As a bus and bike commuter I’ve already benefited from the new lanes, even before the signals were fixed. My bike route includes a left turn onto Brattle, and the dedicated turn lane and conspicuous sharrows make that much easier on the nerves. I do sometimes drive Mt Auburn into Cambridge, usually when traffic is light—evening, weekends—and I’ve wondered why the bus/bike lanes need to be in effect at those times. Would it be possible to lift the restrictions during off-peak hours, similar to the left turn restrictions in Fresh Pond Parkway?

    Thanks again for keeping us all so well-informed.

  4. One question that many were asking is the red bus lane is off limits to cars at all hours or only durning peak hours? There has not been any signage(unless it went up in the past 2 weeks) around this so I’ve stayed out of those lanes. That said, it doesn’t really make sense to not allow cars there when bus/bike traffic(late at night) is almost nil. What was the plan around this as I’ve heard this ask a couple times (and have read through couple of the post but have not seen anything) Thanks in advance! Otherwise, would love to know when benchmarking is done to evaluate the positives and negatives.

    1. On the issue of time of day: The designer’s view was that at rush hour, the lanes are necessary, but off peak, they don’t make a big difference to anyone. So, it’s simpler for everyone to just maintain a consistent pattern of operation.

      But a number of people have asked the same question and it’s irritating to see a lane that isn’t used if one is at all delayed. So, I’m bringing that back to the team.

      Measurement is ongoing, but a fuller assessment will happen in the spring when conditions have fully stabilized.

    2. Those times when bus and bike traffic are light are presumably also times when car traffic should be light, so I think it would be a bad precedent to allow cars to use bus lane during certain hours. It will confuse drivers who are not daily users and will lead to gradual encroachment on the lane at all hours. The only times when bus traffic is “nil” is from 1 to 5 a.m.

  5. I hope that the traffic signals are not going to change in the weekends like it had in the past. That needed improvement and did not make any sense. They should just leave it as is for seven days a week. Yes the past couple of days of commuting has been much better. Thank you

    1. Actually, there is an “off peak” phase that runs between the rush hours, nights and weekends. There are three phases, morning rush hour, evening rush hour and off peak. All very different.

      During the off peak phase Mount Auburn at Coolidge actually gets much more green time (taking it from pedestrians and Coolidge) but Mount Auburn at Fresh Pond does not. So, during the off peak phase, the lights will look out of synch, but they are still working properly.

  6. The bus lane has completely blocked access to storrow drive in the morning from 6am to 11 am. Not only is mt auburn street a crawl, the traffic down Grove street to Greenough Blvd is backed up from the boulevard to Belmont street. If you want to get where you are going downtown you have to take the pike and deal with that gridlock. Too many rats in the box. We will reap the whirlwind by subjecting people to such a stressful start to the day.

  7. A sincere thank you Will for your thankless work on this. You are a true public servant.

    Let me also second all the comments suggesting that outside of rush hour, being stuck in a single lane on Mt. Auburn behind Cambridge-bound traffic when there are no buses running and a clear through lane onto Rt. 16 inbound doesn’t make a lot of sense.

    1. The designer’s view was that at rush hour, the lanes are necessary, but off peak, they don’t make a big difference to anyone either way. So, it’s simpler for everyone to just maintain a consistent pattern of operation.

      I did bring this back to Cambridge and their engineers continue to feel that it would create confusion with little benefit to vary the rules by time of day.

  8. Will,

    Thanks so much for keeping on top of this tricky problem. Hopefully it will work out to everyone’s advantage.

  9. You should read the book Meltdown – what happened over those 10 days is a classic example of the thesis of the book, namely that with technological advances systems became more complex. There were benefits to that, but also greater risk – the complexity meant there were more room for errors, and also because of the reach of technology the impact of the errors are greater now than in the past.

  10. Thank you, Will. Prioritizing public transportation access will benefit everyone. We can all be patient while you and the traffic planners continue to seek best solutions. Cheers! Mike

    1. I am very grateful for helping the riders on the most crowded bus line in the MBTA system more user-friendly by speeding the trip past Mount Auburn cemetery, given that many riders must stand. The update with the light signals at Fresh Pond/Mount Auburn intersection compounds the betterment!

  11. Hi Will, Having driven from Common St. to Harvard Sq. on Thurs. evening in the snow, I found it rather harrowing. Near the Star Market, I found myself several times in the wrong lane. One has to change lanes several times in order to go straight and in the dark, on a snow-covered road, it was quite a challenge! It is a bit like driving an obstacle course. I wonder if the experience will be similar to the recent changes in Cushing Square, where it took months for residents to determine the correct lane and I know that there were quite a few accidents, not to mention near misses, which still occur. Not easy!! God help any visitors!! Thanks, Kent

    1. This sounds like other spots that I rarely travel on. Partial lane shifts for bike lanes and other reasons seem like accidents waiting to happen, especially on snowy roads or rainy nights, and especially for drivers unfamiliar with the road. The new shift for the bike lane going westbound on Beacon Street near Park Drive (near Boston/Brookline line) comes to mind.

  12. Weighing in on the debate about whether the bus lane should be open to all traffic outside of rush hour: on 2 major thoroughfares in Montreal where reserved bus lanes were created years ago, they have always been signed as reserved only during rush hour (M-F, 7-9 and 3:30-6:30 I think), and everyone seems to understand the restrictions, at least after a few months. As long as the signage is clear and regular, it should be enforceable, in my opinion. Thanks for advocating so tirelessly for this.

    1. I get this point and had the same reaction.

      I’ve brought this back to Cambridge and they have a strong sense that it is cleaner to keep it consistent 24/7.

      That is what the red paint means in signal speak — keep off unless you fit one of the other markings (bus, bike, right turn at the very end).

      They feel it is a mixed message that is too confusing and harder to enforce.

  13. The inbound during rush hour between Coolidge Avenue and the 2nd light at Fresh Pond Parkway might need to be improved. It seems as if the lights during that time of day (weekday) were not aligned on Dec. 11. A bunch of cars, about 4, cut into the bus lane between the cemetery and Coolidge Avenue. Can we get updates on how the timing cycles are monitored during late afternoons in the ‘reverse-commute’ direction?

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