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Letter to Mayor Curtatone about signal timing & LPIs

Letter to Mayor Curtatone about signal timing & LPIs

Mayor Joe Curtatone
Somerville City Hall
93 Highland Ave
Somerville, MA 02143

March 29, 2019

Dear Mayor Curtatone,

We wanted to reach out to you regarding recent signal changes on Beacon Street where exclusively phased pedestrian signals have been converted to concurrent phasing.

We appreciate that both City staff and residents are concerned about pedestrian safety and are pressing for more protections for people on foot. You said it yourself in the Somerville Times in 2015: “When you plan for people, you get walkable neighborhoods that create vibrant communities, with faces you recognize of people walking, pushing strollers and biking.”

LivableStreets and WalkBoston have advocated for years to move to concurrent phasing with leading pedestrian intervals (LPI). We ask that you please support the continued implementation of an overall policy of concurrent with LPI pedestrian signal phasing in Somerville, with limited exceptions applied in locations with (1) high volumes of seniors or children, (2) very high turning movements (250+/hour), or locations where data show a special need for exclusive signals.

We recommend:

  • The Leading Pedestrian Interval (LPI) be lengthened to give pedestrians a longer head start.
  • No Turns on Red signs be installed to restrict motor vehicles from turning during the LPI.
  • The concurrent walk signal phases should be automatic and not require a button. This is one of the key benefits of a concurrent signal. The shorter wait times for pedestrians are also shown to reduce the number of pedestrians who cross the street against the light.

At the intersection of Beacon Street & Park Street, 100% of vehicles coming from Park are turning. The City should consider whether an exclusive WALK signal is needed for pedestrians to cross Beacon Street or whether the volumes are low enough that a concurrent signal for the Park Street green phase (for pedestrians crossing Beacon) would be appropriate. There could still be a concurrent phase during the Beacon Street green (for pedestrians crossing Park Street or Scott Street) depending on the turning volumes.

At the intersection of Beacon Street & Washington Street, you might look at the signal timing adopted this week in Central Square, Cambridge. A right red arrow is now displayed during an extended LPI  (a “Super LPI”) which eventually turns to a flashing yellow arrow to remind drivers that they must yield to pedestrians and do not have an exclusive turn.

The reasons for, and benefits of, concurrent phasing and LPI are well presented in the brief by the City of Cambridge which implements LPI/concurrent phasing at almost every signalized intersection. There is also some fairly well documented research on LPI safety that is shared by the National Association of City Transportation Officials (NACTO). Jeff Speck in his recent book Walkable City Rules says, “Keep signals simple: most intersections should be concurrent and quick.” (Rule 74, page 176).

It should be noted that while concurrent phasing with LPI is generally safer and more convenient for people walking than exclusive phasing, there are exceptions. Older residents, people with mobility challenges, and small children in particular may feel more at risk. In most cases, when exclusive phasing is used, it is often near schools or senior centers, or locations with high volumes of turning cars (such as Inman Street at Mass Ave in Cambridge).

With the ongoing construction detours around Union Square there is presently the potential for increased vehicle volumes through these intersections and Somerville could consider combining concurrent and exclusive phasing to get the benefits of both for the duration of the detours.

Another option that could be tried is a push-button activated exclusive phase (noted by signage) that could serve the needs of people who feel uncomfortable crossing during a concurrent phase. Automatic concurrent phases would be retained during the balance of the time.

Sincerely,

Brendan Kearney
Communications Director, WalkBoston

Adi Nochur, Somerville Resident & Vision Zero Task Force Member
Project Manager, WalkBoston

Stacy Thompson
Executive Director, Livable Streets Alliance

Mark Chase, Somerville Resident
Urban Transportation Planner

Jim McGinnis, Union Square Resident

Jon Ramos, West Somerville Resident

Charles Denison, Somerville homeowner Ward 5

Steven Nutter, Somerville Resident Ward 4

Alex Epstein, Somerville Resident Ward 6 & Vision Zero Task Force Member

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