About Davis Square Signal Timing Improvements

Previously, it could take about four to six minutes for pedestrians to legally cross the intersection diagonally. As a result, over 75% of pedestrians cross outside of the pedestrian phase.

In late June 2018, the City of Somerville performed signal timing changes at the intersection of Highland Avenue/Holland Street/College Avenue (aka Davis Square). The most significant change was to remove the previously existing “pedestrian scramble” phase and replace it with crossing phases that occur at the same time as certain vehicle phases. This change helps the intersection run more efficiently, allowing pedestrians to cross when it is safe to do so, and shortening the overall length of time it takes for the signal to make a full cycle, reducing delays for everyone. Vehicles making certain turns now need to yield to pedestrians crossing legally in the crosswalk. Pedestrians are given a “head start” (aka leading pedestrian interval) to allow themselves to begin crossing before turning vehicles enter the crosswalk.

Over the course of an hour...

  • Pedestrians get a “Walk” signal 8 more times
  • Drivers on Highland Avenue get about 3 more minutes of green time
  • Drivers on Holland Street get about 2.5 more minutes of green time
  • Transit users on the MBTA busway get 8 more green signals

Pedestrian Delay Significantly Reduced

  • Previously existing maximum delay was 105 seconds for all crossings
  • New pedestrian delay improves by 24 and 74 seconds depending on crosswalk location/time of day

 

  • Background

  • Presentations and Information

  • Timing Changes at Other Intersections

Please note: The signal timing work in Davis Square is now complete. The text below, which describes the Square's previously existing signal timing, will help to explain the need for improvements.


The signal cycle in Davis Square is over two minutes long, meaning long waits for everybody as they try and get through the intersection. For pedestrians, this is an especially long time, especially in cold, hot, or rainy weather, or if a pedestrian has mobility issues. Depending on when you arrive at a crosswalk, it can take about four to six minutes to legally cross the intersection diagonally (e.g. between Oath and JP Licks). However, many pedestrians have noticed that it’s pretty safe to cross certain crosswalks during parts of the signal phase. At the crosswalk across Holland Street, it’s currently safe to cross during 60% of the signal cycle, but pedestrians are only given 20% of the signal cycle to cross. Similarly, at the Day Street crosswalk, it is safe for pedestrians to cross during 80% of the signal cycle. As a result, pedestrians do not wait for the exclusive pedestrian phase. Over 75% of pedestrians in Davis Square (during observed times) cross outside of the pedestrian phase.

Rather than enforce this unrealistic and pedestrian-unfriendly phasing, we have decided to formalize the safe crossing locations that naturally exist during the signal cycle. This will allow us to make the signal more efficient by removing the exclusive pedestrian phase. When a crosswalk is safe to cross, pedestrians will receive a walk signal. Walk signals will no longer all turn on at the same time, so depending on your direction of travel, you may be able to cross multiple crosswalks with minimal wait. Delay for pedestrians crossing during pedestrian phases will be reduced by 24-70%, improving walkability in Somerville’s most walkable square. Pedestrian phases will now occur automatically, so if you forget to press the button, no worries! You’ll still get a pedestrian signal.

In the next phase of this project (which we will be planning for over the next few calendar years), we are hoping to upgrade the traffic signal equipment to include countdown timers and audible signal indications.

 

The signal timing changes being made in Davis Square are the first in a larger effort by the City to improve flow for all users – pedestrians, cyclists, and drivers. View the main project page for more details.