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Mt. Auburn Street at Aberdeen Avenue Intersection Safety Improvement Project

The Mt. Auburn Street at Aberdeen Avenue Intersection Safety Improvement Project will improve safety and mobility for everybody on the street, whether they're walking, biking, driving, or riding buses. 

We will make changes at the intersection of Mt Auburn Street and Aberdeen Avenue and to Mt. Auburn Street from Belmont Street to Brattle Street. 

What to expect:

  • Improvements for people riding buses, walking, biking, and driving
  • Changes to the layout of Mt. Auburn Street
  • Project installation will include adding a new foundation for new traffic signal equipment, installing new equipment, adding new street markings, and installing flex posts. Look out for installation updates in your email inbox or the project webpage.

Sign up for the mailing list to receive the latest updates.

Implementation Updates

November 22, 2023 Update: Traffic signal and sidewalk work

Traffic Signal Installation Update

On Tuesday, November 21, the City's traffic signal contractor, Dagle Electrical Construction, installed the foundation for the new signal at intersection of Aberdeen Avenue and Mt. Auburn Street.

Next Steps: The foundation will require two to three weeks for the concrete to settle. Once the concrete foundation settles, we will install the new signal arm. We expect this to occur this December. At that time, we will switch traffic operations over to the new signal. We will send out another update before this work occurs.

Sidewalk Impacts

Underground utility conflicts required us to place the foundation of the signal in the path of the existing sidewalk. Crews are now installing a temporary asphalt sidewalk around the foundation. We expect work on the temporary sidewalk to finish today (Wednesday, November 22). Unforeseen circumstances may require some work to finish the week of November 27.

Next spring (2024), the City will replace the temporary asphalt sidewalk with a permanent concrete sidewalk at this location. Over the winter, the City will coordinate with the owners of above-ground utilities to create room for a wider sidewalk. The new sidewalk will span the width between the traffic signal foundation and the curb.

Project Expected to Finish Spring 2024

We expect that once the new signal is operational, it will be too cold to complete the remainder of the project this winter. New pavement markings to extend the separated bike lane and make other changes to the layout of the street will occur in the spring of 2024.

November 3, 2023 Update: Traffic Signal Foundation Installation

Beginning the week of Monday, November 6, the City's traffic signal contractor, Dagle Electrical Construction, will begin installing the foundation of a signal mast arm at the intersection of Aberdeen Avenue and Mt. Auburn Street.

  • Where: The work will take place on the south side of Mt. Auburn Street opposite Aberdeen Avenue.
  • When: Work will take place one to two days next week between 7 a.m. and 3 p.m.
  • What will happen: The contractor will excavate the ground and pour new concrete. Crews will work on Mt. Auburn Street and there will be daytime lane closures. No interruption to signal operations is anticipated at this time. 
  • Next steps: Once built, the foundation will require two to three weeks for the concrete to cure. Once the concrete foundation cures, we will install the new signal mast arm. We expect this to occur in late November/early December. At that time, we will switch traffic over to the new signal.

Project Expected to Finish Spring 2024

At this time, we expect that once the new signal is operational, it will be too cold to complete the remainder of the project this fall. New pavement markings to extend the two-way separated bike lane and make other changes to the layout of the street will most likely occur in the spring of 2024.

Project Plans

Click here to view the final engineering plans. This includes plans for pavement markings, flex-posts and signals.

See below for a project roll plan, which is a graphical display of the same plans. Click here to view a copy of the roll plan at a higher resolution.


What's Changing?

Improvements for People Riding Buses

We will improve bus reliability by extending the shared bus-bike lane about 500 feet to the Homer Avenue bus stop. We will also make changes to signal timing to improve bus travel time reliability. 


This project is guided by the City's Complete Streets Policy, Bus Delay and Unreliability Studies, and Transit Strategic Plan. More information on transit planning in Cambridge can be found on the Community Development Department's website.

This project will address concerns with the current traffic pattern that we installed in 2017, that we were unable to address with the previous signal infrastructure. Additional information about the traffic pattern changes from 2017 can be found on the Community Development Department website.

Improve Safety for People Walking

This project will make improvements to pedestrian signals at two intersections: Mt. Auburn Street at Homer Avenue and Mt. Auburn Street at Aberdeen Avenue. This includes:

  • Changes to signal timing to allow pedestrians more time to cross the street.
  • "Split-signal timing" at Aberdeen Avenue, which will allow people to cross without traffic turning into the crosswalk. 
  • Improvements to signal equipment to make it easier for people with disabilities to use.

This City is continually making improvements for people walking on a citywide basis. This includes a number of active initiatives identified in the City's Pedestrian Plan, such as:

  • Limiting the number of new curb cuts approved in the city.
  • Installing street trees, benches, bus shelters and other amenities.
  • Rebuilding streets and sidewalks as part of the City's Five Year Plan for Streets and Sidewalks.
  • Repairing existing sidewalks and ramps citywide on an ongoing as-needed basis.

Improvements for People Biking

We will improve bike facilities with a combination of quick-build separated bike lanes, shared bus/bike lanes, and standard bike lanes.


Mt. Auburn Street is called out in the Cambridge Bike Network Vision as streets for "greater separation." Greater separation means that bike lanes are separated from vehicle traffic with barriers or curbs. This project will improve bike facilities on both streets without changing existing parking.  

This project will look at other types of bike facilities in addition, including bicycle-specific ramps and signals.

Bicycle-specific ramps allow people biking to cross the street without having to merge across traffic. People biking can take a ramp up the same level as the sidewalk and turn to cross the street at their own crossing. Specific ramps, markings and signals for bicyclists help keep bike and pedestrian traffic separate and create a more comfortable experience for people riding bikes. We install these throughout the city in locations where bicycle traffic must turn left across a busy street. (Image: Example of a bicycle ramp in Porter Square)

Bike Lane Types 

Below, learn more about the types of bike lanes you will see on Mt. Auburn Street. 

Separated Bike Lanes

Separated bike lanes provide dedicated spaces for people riding bikes, physically separated from traffic by a vertical structure like a curb, flex-post, or other barrier. Compared to traditional bike lanes, more people are comfortable biking in bike lanes that are separated from traffic with a barrier or curb. The experience is also much more comfortable than riding in traffic with cars, buses, and trucks.

Separated bike lanes also increase safety for people walking by reducing crossing distances at crosswalks and visually narrowing the roadway. As we install separated bike lanes, we also look for opportunities to increase visibility at intersections, refresh crosswalk markings, and install appropriate pedestrian crossing signs.

The left image shows Inner Mt Auburn St with a standard bike lane, travel lane, and a parking lane. The right image shows Inner Mt Auburn St with a bike lane, buffer area with flex posts, a travel lane, a parking lane, and daylighting.

Example of a separated bike lane on Mt Auburn St 

On-Street Bicycle Lane (Standard Bicycle Lane) 

On-street bike lanes provide space for bicyclists to ride out of the way of moving traffic, but do not provide a physical barrier between people riding bikes and people driving.

parent and child on bike

Example of an existing on-street bicycle lane on Mt. Auburn St

Shared Bike/Bus Lanes 

Shared bike/bus lanes are dedicated lanes for both buses and people riding bikes. Compared to separated bike lanes, they are a less comfortable facility for people biking, but they are more comfortable than riding in mixed traffic. The city installs shared bike/bus lanes only in locations where space for a dedicated bike lane is not yet available.

Example of a shared bus/bike lane in Boston

Improve Safety for People Driving

As part of this project, we are looking at ways to improve safety and clarity for people driving. This will include:

  • Adding dedicated turn lanes, which provides dedicated space for cars to wait to turn, so that they won't block cars going straight.
  • Replacing and upgrading all traffic signal equipment at the Mt. Auburn/Aberdeen intersection. This will include a dedicated signal for traffic turning left onto Aberdeen Ave. The turn signal will hang directly above the left turn lane, making the intersection easier for drivers to understand.
  • Reducing conflicts between cars, people walking, and people biking. Traffic turning right will get a dedicated time to turn, separate from people walking in the crosswalk and people biking.
  • We will remove one travel lane, so there will be a single lane for traffic headed west toward Belmont and Watertown. We're able to make this change with limited impacts to traffic by adding turn lanes and making changes to signal timing.
  • There will be no changes to parking on the street.

Past Meetings

Project Open House: September 12, 2023

On September 12, from 5 p.m. to 7 p.m., we hosted a drop-in project open house which took place outside the Star Market at 699 Mt Auburn St.

At the Open House we:
  • Discuss updated plans for the design of the project
  • Provide information regarding next steps, including the schedule for project implementation
  • Informally discuss the project with attendees

Click here to view materials shared at the open house.

Click here for more information.


Virtual Community Meeting: August 23, 2023

On Wednesday, August 23, 2023 from 6 p.m. to 8 p.m., we held a virtual community meeting over Zoom.

Meeting Materials

City staff gave a presentation regarding project background, relevant city policies and ordinances, and shared the revised plans since the Project Open House in May. Attendees had an opportunity to provide feedback and ask questions.

Next Steps

Meeting Update

Please review the slides, recording, or transcript for a full overview of what was discussed during the meeting.

Revised Design Key Features
  • Two-way separated bike lane on the north side of the street. This revised the previous design of a one-way bike lane on either side of the street.
  • No left turn from Mt Auburn St directly into the shopping center. Left turns will access the shopping center by turning left onto Homer Ave and using the Homer Ave entrance.
  • Changes to signal timing to improve crossing Mt Auburn St on foot. This includes providing more time to cross the street and reducing the wait time for a green walk signal.

Community Open House: May 24, 2023

On Wednesday, May 24, from 4:30 p.m. to 6 p.m. at the Collins Branch of the Cambridge Public Library (64 Aberdeen Ave), we held an open house to discuss the Mt. Auburn Street at Aberdeen Avenue Intersection Safety Improvement Project.

During the open house, we:

  • Shared plans for changes to Mt Auburn Street, between Belmont Street and Brattle Street
  • Provided background on the city goals and policies, such as Vision Zero, the Cambridge Bike Plan, and other nearby city projects
  • Discussed the project with residents and abutters and take feedback 

Click here to view materials shared at the open house.

This was not the only opportunity to hear about the project from City staff: we will be holding a more in-depth online community meeting later this year. Sign up for the project email list to stay informed.

Email the Project Manager

Email Project Manager Andreas Wolfe at awolfe@cambridgema.gov if you have a question or comment that you would like to receive a response to. 

Nearby Projects

Brattle Street Safety Improvement Project

The Brattle Street Safety Improvement Project installed separated bike lanes and pedestrian crossing islands on Brattle Street. These safety improvements were made between spring and summer 2023. 

The separated bike lanes on Brattle Street end at the intersection of Brattle Street, Mt. Auburn Street, and Aberdeen Avenue. The Mt. Auburn Street at Aberdeen Avenue Intersection Safety Improvement Project will connect to the Brattle Street project. 

Brattle Street Safety Improvement Project Plans 

Image shows plans for the Brattle Street Safety Improvement Project. Separated bike lanes will end at Aberdeen Avenue.

Click to enlarge this image. 

Huron Avenue and Cushing Plaza Improvements Project

As part of the Five-Year Street and Sidewalk Reconstruction Plan, Huron Avenue is being reconstructed between Fresh Pond Place and Fresh Pond Parkway. Improvements include adding three new fully-accessible crosswalks, making improvements to existing crossings, adding a two-way separated bike lane along the Fresh Pond Reservation, and planting trees. 

A future project will add quick-build separated bike lanes to Aberdeen Avenue, connecting the Huron Avenue bike lanes to Mt. Auburn Street. The City is coordinating with utility companies to determine the best time to start this project, which will have no impacts on existing parking. 

Click here to read more about the Huron Avenue and Cushing Plaza Improvements Project

Illustration of a planned two-way bike lane on Huron Avenue. The separated bike lane is on the same side of the street as the Fresh Pond Reservation


Project Background

Project Documents

Engineering Plans

Roll Plans

Meeting Materials

Project Area

This project covers Mt. Auburn Street between Belmont Street and Brattle Street.

Click here for to view a larger project map.










Cycling Safety Ordinance

In 2019, the Cambridge City Council passed the Cycling Safety Ordinance. The 2019 Ordinance requires the City to install separated bike lanes when:

In 2020, the Cambridge City Council passed amendments to the ordinance, requiring the installation of about 25 miles of separated bike lanes within the next five to seven years. The ordinance requires that the City install separated bike lanes on:

  • All of Massachusetts Avenue
  • Garden Street, eastbound from Huron Avenue to Berkeley Street and westbound from Mason Street to Huron Avenue
  • Broadway from Quincy Street to Hampshire Street
  • Cambridge Street from Oak Street to Second Street
  • Hampshire Street from Amory Street to Broadway
  • 11.6 miles in other locations from the 2020 Bicycle Plan

Other Streets and Transportation Projects

Looking for information on other streets and transportation projects in the City? Three City departments collaborate on the design, community engagement, installation, and construction for street and transportation improvements: the Community Development Department, Public Works Department, and Traffic, Parking, and Transportation Department.

Page was posted on 8/24/2021 5:10 PM
Page was last modified on 11/3/2023 9:28 AM
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