About the Traffic Signal Timing Improvements

The City of Somerville has generally improved equipment and updated traffic signal timing during large construction projects like the Somerville Avenue Streetscape project from Porter Square to Union Square and the East Broadway Streetscape. While big capital projects are one opportunity to do this type of work, traffic patterns and volumes can change over time. The Transportation and Infrastructure division of OSPCD is starting to study signal timing at intersections not undergoing major capital projects in an effort to improve flow for all users – pedestrians, cyclists, and drivers.

Signal improvement will not change overnight, this will be a several-years-long process but it’s happening at an important time. The City of Somerville will see unprecedented construction over the next few years. Bear with us. These are some of the changes you may see:   

  • Changes to signal timing: The timing for each ‘leg’ of the intersection will be studied. Since our signal timing equipment is old enough, many intersections have the same signal timing whether it’s morning or evening rush hour or the weekend even though everyone knows that traffic is different at different times of day!  The timing of the intersection will be studied to try to match traffic flows.
  • New signal indications: Primarily new turn arrows.
  • Concurrent pedestrian phasing: Instead of exclusive pedestrian phasing (meaning the walk sign is on for all movements in an intersection while all other movements have a red light), pedestrian signals will be on at the same time as drivers get a green light. This means that drivers will have to yield to pedestrians during turning movements.
  • Technology to give priority to buses and emergency vehicles.
    • Bus Jump Lanes: In rush hour, the 88 bus carries at what the MBTA considers over capacity or over 56 people on board. The numbers are similar for the 101 and 85 buses. Bus jump lanes give buses a dedicated space in busy intersections so they can ‘jump’ to the signaled intersection after loading/unloading passengers. These improvements done over the length of a bus route result in better reliability and on time performance.
  • Bike signaling and/or signage indicating legal cyclist movements.
  • Blinking Signals: Late at night and in early am hours, lights that are turned to either red or yellow blinking to make the intersection work like a 2- or 4-way stop.
  • Signal Timing Projects


Keep checking back here as new projects are added.