Eyes On the Street: Somerville Builds Gardens In the Street to Improve Safety While Also Reducing Water Pollution

The new 'green infrastructure' helps calm traffic and improve safety while also absorbing stormwater during rainstorms.

4:12 PM EDT on July 30, 2025

A garden full of grasses and pink coneflowers lines the curb of a city street through a residential neighborhood. In the foreground, on the near side of the garden, is a sidewalk with a newly-planted tree next to an asphalt-paved bike lane. On the far side of the garden, a white SUV travels on the street. Behind the car is a red-painted crosswalk marked with two diamond street signs. — A new stormwater filtration garden provides a buffer between motor vehicle traffic and the bike lane and sidewalk along Summer Street in Somerville.

In the Spring Hill neighborhood of Somerville, the city is wrapping up a three-year construction project that tore up and completely rebuilt several residential streets as part of a major sewer replacement project.

The primary goal of the Spring Hill sewer separation project was to replace 19th-century sewer pipes that frequently flooded and overflowed into local waterways during rainstorms.

But because the project required the city to rip up entire streets to replace the pipes underneath them, it also created an opportunity to redesign these streets from scratch, with new speed humps, protected bike lanes, and raised crosswalks.

The project also replaced thousands of square feet of what had formerly been asphalt parking areas with new gardens designed to absorb runoff during rainstorms.

Many of these gardens are located at intersections and crosswalks, and thus serve the additional purposes of calming traffic, reducing the heat island effect, and improving visibility for pedestrians (and more subjectively, some might argue that they're considerably more attractive than an asphalt parking spot).

When we first wrote about this project last year, Dan Amelin, a City of Somerville engineer, told StreetsblogMASS that all these new tree plantings and gardens add up to about 6,750 square feet of new green space for the city.

Some of the biggest changes are visible on Summer Street, where the city upgraded what was formerly a paint-only bike lane with a new curb-protected design to afford some physical separation between cars and bicycle users who are climbing up Spring Hill from Union Square.

A residential city street lined with multi-story apartment buildings. A blue street sign in the center of the photo at an intersection on the opposite side of the street says "HARVARD ST." In the foreground a green-painted bike lane runs along the near side of the street from the left edge of the photo to the lower right corner. A garden with trees and shrubs lies between the street and the sidewalk on the opposite side of the street. — The intersection of Summer Street (foreground) at Harvard Street near the top of Spring Hill in Somerville, picturing one of the street's new stormwater filtration gardens (next to the street sign), and the new curb-protected bike lane (foreground) that climbs up Spring Hill from Union Square.

On Central Street, which is one of the few streets that crosses the width of Somerville from Broadway in the north to Somerville Avenue in the south, the project installed a pair of sidewalk-level bike lanes on either side of the street.

Central Street is now one-way for cars, but it's a two-way street for bike traffic, with multiple new high-visibility raised crosswalks.

A city street lined with small 3-story multi-family residential buildings. Two concrete curbs in the middle of the street divide a single lane of motor vehicle traffic from two sidewalk-level bike lanes on either side. White zebra-striped crosswalks cross the street every block into the distance. The street is also lined with leafy trees of varying sizes and ages, some of which are very large and mature, others of which have just been planted. — New sidewalk-level curb-protected bike lanes and crosswalks Central Street, looking north from Summer Street towards Highland Avenue.

A future phase of work – tentatively scheduled to begin construction in the city's 2026 budget year – will tear up Highland Avenue to replace its sewer pipes and other underground utilities.

City officials have also committed to installing new protected bike lanes on both sides of that street from Davis Square to the McGrath Highway when that underground work is complete.