Trapelo/Common Intersection Changes

As you may recall, last fall we tried unsuccessfully to change the light phasing in Cushing Square. After several weeks of confusion and some near misses, we went back to the original, pre-project configuration.

So, currently that intersection is working as it has for many years: cars on Common Street headed towards Watertown get green left and green straight at the same time while cars headed down the hill into Belmont get red. Then, that reverses. This is very inefficient because most of the traffic in both directions would like to go straight. One wants the two straight movements to share green time.

After a lot of debate, a new approach has emerged which should be clear for drivers and is actually more efficient than any of the previously attempted configurations.

The engineer’s explanation of this new approach appears below (with some additions from me):

  • For the vehicles going east or west on Trapelo Road there will be no change.
  • The south bound (up-hill toward Watertown on Common Street) lights will have a left arrow and a green ball light that still turn green simultaneously.
  • But, the south-bound green arrow will turn to red while the south bound straight ball light remains green.  Vehicles on Common Street heading toward Watertown will be able to continue towards Watertown.  But vehicles in the left turn lane and turning left onto Trapelo Road will have to stop before the Common Street through movement stops.
  • When the south-bound left arrow goes red, the north-bound (downhill from Watertown on Common Street) lights will go green for both north bound lanes.  For south bound vehicles on Common Street in the right lane and heading toward Watertown they will find that, during the latter part of their green phase, traffic will start coming from the opposite direction of Common Street and some of that traffic will be wanting to turn left in front of them.
  • The north bound vehicles will see green balls only (no left arrow),  as is common at many intersections.  There will be a “left-turn-yield-on-green ball” sign, again as is common at many intersections.  For vehicles on Common Street coming from Watertown, they will now find that traffic will be coming from the opposite direction of Common Street when they have the green indication and the vehicles turning left into Trapelo Road toward Waverley Square will need to yield to traffic coming from the other direction of Common Street.

The beauty of this approach is that (a) the signage will be simpler — the complicated signs with three-headed arrows will be less critical; and (b) if north-bound traffic makes the mistake that it tends to make — thinking that the straight move to continue on Common Street is a left turn, they will actually not conflict with the straight movement from the other direction.  The  only time they will need to think is when they are making the hard left onto Trapelo and on that movement, it is reasonable to expect the drivers will exercise the caution that they normally should on a left turn with no arrow.

The new traffic pattern will go into effect on Tuesday, May 31

Published by Will Brownsberger

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

54 replies on “Trapelo/Common Intersection Changes”

  1. Despite the improved signage, there are still north-bound drivers in the left lane of Common Street who do not understand that they should be turning left onto Trapello Road. As matters stand there are still near misses between north-bound drivers in the two lanes. On-coming traffic will only make this more dangerous. Hopefully I am missing something!

    1. We hope that north-bound drivers will take more care when they see a left-turn-yield sign. The green left arrow will be replaced by a green ball and the yield warning.

      There will be a lot of professionals watching how it goes.

    2. I agree completely. For years we would only use the right northbound lane coming down the hill for left turns on Trapelo or to cross into the street that goes between the UPS Store and The Frame Shop. Cars going straight down across the intersection on Common St. would use the LEFT lane. Then it changed last year and a lot of motorists still used the left lane to go straight which I thought the police should have monitored as I had a number of instances of cars that would have struck me from the left lane had I not given way to them. Now seems it has been made a game of who can get there first with both lanes going straight which seems to me very dangerous.

  2. I’ll be very sorry to lose the protected left from northbound onto Trapelo. The equivalent turn from School St is already risking one’s life. We are running out of safe, efficient ways to get home to west Belmont from Watertown.

  3. so many fixes and why- it seems to be working just fine.
    Maybe they could work out why there are such bad backups on Trapelo- my answer is that it’s now too narrow. Travel at rush hours is ridiculously bad.
    And maybe they could finish the sidewalks in Waverley Sq. – Wheelworks/Pho Thai- and at Harriet and Trpelo.

    1. It’s not the narrowness — the traffic flows fine between intersections.

      But there appear to be problems with the light timing in Waverley that the team will be working on. We are getting a lot of complaints about Waverley.

  4. Who choose the ENORMOUS light structures? The lights are so high now that you can’t see them when you pull up to stop. You have to sit forward in your car and look up because they are so high up. They’re very ridiculous! Way overkill.

    1. I agree. If they’re going to be up so high (for the trolley wires?), there need to be lower ones so people can see the lights when they’re in the intersections. This is a problem with all of the new signals.

      1. I AGREE!! This one of my top pet peeves about the project — the HUGE highway-sized light signals the entire corridor. I am always leaning forward looking up into the sky, which really is a safety issue since there is no longer any peripheral vision. I am still looking for similar signal light heights (and huge poles and street signs) in other communities — there are none!(except on route 9 Natick). I really hope these lights can be lowered to a more standard height.
        As a side note, the vision was always to create neighborhood/pedestrian friendly squares as destinations (like Belmont Ctr). But this somehow got lost in the scope, design and choice of fixtures/materials. Similar to Belmont Ctr (and Arlington, Watertown,Waltham, Lexington, Cambridge, etc), I was expecting the decorative lamp posts in the squares, benches and the brick pavers, not the pink concrete on sidewalk curbs and islands. Such a lost opportunity 🙁

        1. As a senior citizen it pains me to see our towns spending our money and all it seems only for show. Enormous signs and poles for the visually impaired that make it seems we are pawns in some kind of a board game and big bumpouts dangerously sticking out into main streets and impeding the general flow of traffic. I’m told that is to “calm” the traffic but, please believe me, no longer being able to use the natural two lanes and restricting them to only one lane only succeeds in enraging drivers. Do the labor and trade unions have such a stranglehold on our towns that we are obliged to give them such silly “make-work” projects?

          1. This project was designed under the guidance of volunteer citizens of Belmont serving on the Traffic Advisory Committee.

            We can disagree about the merits of traffic calming but let’s not question the good faith of the people who put it together.

            For the record, I think it is huge a safety improvement — cars are driving the speed limit, not the speed limit plus 10 or 20, as before.

      2. Agreed! I cant’ see the lights if I’m the first car at a stoplight because they’re so high now. A dangerous situation.

    2. The enormous supports for the new lights are a direct response to anticipated extreme wind and weather due to either the coming Ice Age or climate change, take your pick. In any event, engineers have decided that these structures will withstand those extremes. Maybe the stop lines need to be repainted a little further back so that drivers will be able to see the lights at their new height.

  5. Good plan, Will. I think it should work for drivers without hampering traffic. Thanks, Sallye

  6. The biggest problem I see is that Northbound traffic uses the left turn lane to go straight on Common, cutting off the people who read and follow the signs. Shared straight on green makes sense but maybe some police enforcement of the signals is also called for.

  7. Crossing these streets is still very difficult . First, you wait forever for a walk light. If I am crossing common from Vicki Lees to Cushing, cars are turning right from Trapelo Road to Common. Isn’t there a no right turn sign there ? If I am crossing Trapelo Road past the square going west toward Waverly, cars do not stop at the crosswalk. They just go flying by. It’s just a matter of time ! The laws should be enforced here to protect pedestrians.

  8. If I read this correctly it seems that the northbound traffic will now have two lanes crossing the intersection into the one northbound lane across Common Street which seems to me very dangerous and will cause accidents.

  9. Thanks for the efforts at Cushing sq. Will wait to see how it goes.

    I know this is a little off subject her but:

    Is there any chance that you could work with the engineers who configured the lights at the bottom of the Grove St hill intersection with Greenough Blvd.
    Those lights are also out of sync also. When one comes to the bottom of the hill and there is no traffic on Greenough, the lights take about 3-4 minutes to cycle greens for no traffic as you sit and wait to turn on a green. I have seen many people just turn because they think the light must be out of order or they are just frustrated as I am. Not only did the reducing to one lane each way slow things down, now the lights are a problem. There should be also an arrow painted on the turn lane coming from Cambridge. Many people who are going straight just sit there to do that while the people turning right to go up the hill may have to wait 2 light cycles at rush hour.

  10. The “left-turn-yield-on-green-ball” light is, by its very nature, a safety hazard. Case in point, the left onto Common from Mount Auburn, near the cemetery.

  11. What is the plan for the lights at Grove and Belmont St. The least there should be a left turn signal for cars going east on Trapelo Rd or a delayed green for cars going west on Trapelo rd.

    Thanks for your help

  12. It’s interesting to me that the design of the bump out in front of the UPS Store has changed the feel of the intersection when driving north on Common from Watertown. Proceeding north is now visually a slight left turn, and feels like a left turn when driving. It is easy to see why drivers are confused.

    I hope the new changes work, tho I share the concerns of others here.

  13. Now that this problem has been addressed send some of these traffic engineer geniuses to straighten out the signal timing in Waverley Square. I was on the bus twice this week (around 3:00, before rush hour) and the traffic was backed up all the way to the Beech St. intersection. The pedestrian light stays red for way too long, and as the light at Shaws turns green the one at Agasizz turns red, and then the light at Pleasant St. stops you in another 100 feet. Too many uncoordinated signals in way too short a stretch of road.

    1. I second this motion… this now appears to be the most congested area in Belmont, all due to the timing of the lights, and way before rush hour begins.

    2. Regarding Waverley
      From the Town Engineer — improvements expected shortly.


      I spoke with the Mass DOT engineer and the problem in Waverley Square stems from the Shaw’s driveway. For many years , prior to the signals being added at Trapelo and Pleasant, motorists on Pleasant Street would cut through the Shaw’s parking lot to beat the challenge of taking a left from Pleasant to Trapelo at the un-signalized intersection. Even though the intersection is now signalized, motorists continue to cut through the parking lot. The traffic signal subcontractor was made aware of the long cue developing in the Shaw’s lot (I don’t know who reported it) and changed the timing of the signals to help ease the problem. This resulted in shorter green times on Trapelo Road which has caused a ripple effect back to the Mill Street intersection.

      The signals at Mill Street, Pleasant Street and Lexington Street are interconnected and are designed to function together. By changing the timing at the Shaw’s drive the performance was impacted – the Lexington signal fell out of synchronization with Mill and Pleasant.. This will be corrected soon if it hasn’t happened already (I went through last night at 4pm and 5 pm and it seemed better). Once corrected the traffic flow from Mill to Lexington should move much better. One reason for the congestion travelling from Mill to Lexington is that there is not a sufficient gap in the cue heading to Waverley Square because the Lexington signal is all backed up.

      Ultimately, we cannot accommodate motorists cutting through the Shaw’s lot. Some enforcement will be necessary.

      Thanks, Glenn Clancy

      1. Folks cutting through the Shaw’s lot has long been a pet peeve of mine. Not just from a traffic flow perspective but also the negative impact on the people that are trying to park/shop at Shaw’s. Has there been any discussion of enforcement?

          1. I checked in with the town on this: Increased enforcement raises a host of complicated issues and may or may not work well, but the police do intend to communicate through social media to discourage cut throughs.

  14. Will,

    I noticed that the walk signals don’t work unless you press the beg buttons. This results in pedestrians waiting much longer then need be to cross. Are there plans to fix this, or is this the plan?

    Also, gaps in the Belmont-Trapelo sidewalks by Moozies make it very difficult to navigate safely by foot especially for children and the elderly. Coupled with walk signals that aren’t working, this intersection seems quite unsafe. It would be nice if more thought was put into pedestrian safety during construction.

  15. Hello Will,

    Thanks for the update.

    While we seem to be making progress at Cushing Sq, there is an emerging issue at the Belmont/Grove/Arlington St intersection. The new traffic lights that have been installed are leading to confusion. I was on Arlington St heading north yesterday when the car in front of me proceeded directly into traffic against the red light!

    I suspect the problem is that the new traffic light for Arlington St north bound is VERY high in the air, however, the other traffic lights (for Templeton Pkwy, etc.) are much lower AND still visible directly in the center of view for drivers on Arlington St., leading to confusion.

    I believe this also needs investigation quickly, before we start to see accidents happen at this intersection due to less than ideal signal design.

    Feel free to move this to a new thread, or existing if there’s already one on this topic that I missed.


  16. I don’t quite understand it yet but I’m guessing it will be clearer once it begins. Last September I saw so many near-misses in that intersection. One thing that would help is to repaint the lines in the intersection, which are already fading. The left-turn dashed lines through that intersection were helpful but have already faded a lot (in just 6+ months) so are less visible.

  17. Recently I noticed that the Left Lane/left turn sign at Common at the base of the hill intersecting with Trapelo includes the letters: WB . Now I know that Will is concerned about this intersection but doubt those are his initials on the sign! It took several confrontations with this sign before the words West Bound occurred to me. I think this is unnecessarily obscure! Just the word “west’ might make more sense by the left turn sign and could fit if the letters we not as large as the curious WB. Intersection options are confusing enough not to add to the problem with abbreviations like this!

  18. Thank you you for your continued effort, Will. The new signal phasing appears to work quite well, which is a positive surprise for me.

    There are, however, some things that the phasing does not address:

    Speed: speeds on Common Street are up significantly compared to pre-construction. Casually looking at traffic appears that the slowest 10% of cars now go as fast as the fastest 10% used to go pre-construction, especially Southbound. The width and number of vehicle lanes probably has to do with this.

    Bike accommodations: The pre-striping markers on Trapelo Road near Common Street put people riding bikes right into the door zone of parked cars. This should not be called a bike lane – if it is even intended to become one. The bike lane should not end at ANY stretch, no matter how short in the corridor.

    There should be bike lanes on Common Street. The street is certainly wide enough.

    Coming South on Common Street, the first parking stall after Palfrey Road sticks out way to far into the road, creating a choke point for people on bikes, who have to merge into traffic to pass.

    Bike Racks: I have counted 2 bike racks on Common Street since they were installed. This is so obviously insufficient. People do bike in Cushing Square. It will also damage the trees as there are almost no other options to lock up a bike. There should a bike rack every 2 to 4 parking spots – it’s a really cheap way to reduce parking demand.

    Pedestrian Crossing: to cross Trapelo one has to press a button to get the pedestrian walk signal. It does not seem to change any of the signal phases. This begs the question: why does one have to press the beg button? Why doesn’t the walk signal just come on by itself?

    Parking: the new parking stalls effectively reduced the number of available spaces by allocating space for a 1950’s Cadillac even to small cars. This worked just fine before and is now over-regulated.

    Loading zones: There aren’t any legal ones but the hydrant in front of Pilgrim’s shoe repair and Pedego Electric Bikes has become a defacto loading zone. This practice blocks several stores visually for a significant time per day. Otherwise trucks simply double park, proving that the current number of travel lanes are actually not needed for traffic to flow.

    Quality of work: there are at least 3 cracks in the new concrete sidewalks between the UPS Store and the Spirited Gourmet.

  19. What about Belmont st and Templeton Pkwy and Arlington st. The amount of near.misses is an occurance.with every light change. Templeton and grove both get green

  20. This intersection is still not working as well as it used to before all the changes. In addition to all the bike lane issues mentioned by Michael, I see two additional problems:

    1) The northbound traffic line to go straight into Belmont from Watertown gets very long, backing up all the way up the hill. As Sam mentioned back in May, drivers now simply bypass this line by going into the left turn lane, which is frequently empty, and then just cutting back into the straight lane, causing further near misses and cutting off those who waited patiently through several lights.
    2) The intersection as is does not have adequate room for the rare true left turners to wait. The left turning cars pull forward and then block the intersection. People who want to go straight end up having to go around way to the right, aiming directly at the UPS store, and then pull back to the left again at the last second. This gets even more dangerous when the people using the left turn lane to cut get behind a true left turner.

    Could we ask Glenn Clancy and traffic engineering to look at this area again? The problems have just not been solved. Thank you!

    1. Thanks, Liz.

      I’m a very regular user of this intersection. Admittedly, not always in a car, but I think I see it the way most people do.

      I agree that not everyone is following the rules, but I think it is much better than it was after the first rough roll out.

      I’ll watch it more with your concerns in mind, but I’m not of a view that we should recall the engineers’ attention to it.

      Feel free to call my cell if you’d like to discuss: 617-771-8274.

      All best,


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