Broadway Safety Improvement Project

Section A:

• Final Engineering Design

We're moving the bus stop at Windsor St to the far side of the intersection. This move is to improve bus reliability and provide a more accessible stop location.

Click here to view on its own screen

The design team conducted field survey in the Fall of 2024. This included measuring the width of the roadway at various locations. The roadway width determines how key features such as bike lanes, parking and travel lanes are laid out. Street widths on Broadway vary. A map of roadway widths along the corridor can be found here. 

Project Area

The project limits are between Quincy St Portland St. A map is provided below.

Click here for a larger version of the project map. 

We counted existing parking and loading along the street and have included a map and tally of the spaces below.

Click here to see the parking map in full definition.

Existing Parking Spaces Tally

The project team reviewed detailed crash reports from Broadway for a three-year period between January 1, 2022 and December 31, 2024. This data was supplied to city staff from the Cambridge Police Department. Staff reviewed details of each crash to distinguish common trends and factors that lead to injuries along the corridor. 

A brief summary of the data is below:

In preparation for this project, we collected parking occupancy data along Broadway. The data is below. Click the caption to view each map in a larger format.

About this data

Data was collected at 2-hour increments on a Thursday, Friday, Saturday in October between 8 am and 10 pm and Sunday between 8 am and 12 pm. The maps display the data over 4-hour averages. 

View the Data

A fully downloadable database can be found here.

Weekdays 8AM - 12PM

Weekdays 12 PM - 4 PM

Weekdays 4 PM - 8 PM

Weekdays 8 PM - 10 PM

Saturdays 8AM - 12PM

Saturdays 12 PM - 4 PM

Saturdays 4 PM - 8 PM

Saturdays 8 PM - 10 PM

Sunday 8 AM - 12 PM

In Fall of 2024, we collected baseline data about the street

• Click here to view all traffic data collected September 2024

Data Collection Summary

• Turning Movement Counts at 8 locations
  • Broadway at Quincy St/Cambridge St at Quincy St (These two signals operate as a single intersection due to their close proximity)
  • Broadway at Trowbridge St
  • Broadway at Ellery St
  • Broadway at Lee St/Fayette St
  • Broadway at Inman St
  • Broadway at Prospect St
  • Broadway at Columbia St
  • Broadway at Windsor St
• Automatic Traffic Recorder (ATR) counts, which include vehicle speed data and bicycle counts, at 2 locations
  • Broadway at Trowbridge St
  • Broadway at Highland Ave
  • Broadway at Boardman St

Key Findings

• Depending on the location, there are about 350 to 450 people biking on the street today, about 7% to 10% of total traffic on the street, despite poor bike infrastructure on the street today
• Driver speeds are highest near the intersection of Highland Ave, in the downhill direction, towards the High School. Over half of drivers travelled above the 25 mph speed limit.
  •  5% of drivers travelled faster than 37 mph heading down the hill, 12 mph over the speed limit

We will compare baseline counts with counts performed after the project is complete. This will let us review the project's effect on people's behavior; for example, we can see if people drive slower or more people chose to bike on the street.

The city recently published an updated data report about biking in Cambridge. Click here to view the report.

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

• Roads are being reconstructed as part of the City’s Five-Year Plan for Streets and Sidewalks
• AND those roads are designated for greater separation in Cambridge’s 2020 Bicycle Network Vision

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

Mt Auburn St at Holyoke St - Before and After

The images below show Mt Auburn St at Holyoke St before and after separated bike lanes were installed as a part of the Inner Mount Auburn Safety Improvement Project.

Key Components of Separated Bike Lanes

• Bike lanes create dedicated space for people who are biking.
• Buffers (painted lines on the street) create space between people biking and people driving. They help prevent unintentional collisions that could cause serious harm to the people involved. Depending on the location, there may be a parking lane next to the buffer area. In these instances, drivers can use the buffer area to safely get in and out of the car and to load and unload items.
• Flex posts are placed in the buffer area and serve as a vertical barrier in the buffer area.
• Travel lanes allow space for people to drive down the street, but can be used by anyone.
• Green markings help alert people turning from the travel lane that they should look out for people on bikes. These are generally installed at intersections and across driveways.
• Parking creates space for people to store their vehicles while they are in the area. This part of the street may also be designated as loading zones, which help make it easier for delivery people to do their jobs.
• Daylighting is when the parking lane is pulled back 20 feet to make it easier for people driving down the street and people waiting to cross the street to see each other. These areas are generally marked with lines on the ground. There may also be flex posts.

Why Install Separated Bike Lanes

Separated bike lanes provide more space and vertical separation between people on bikes and people in cars. More people are comfortable biking in separated bike lanes than in traditional bike lanes or in traffic with cars, buses, and trucks. Separated bike lanes also increase safety for people walking by reducing crossing distances. 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.

In Cambridge, we take a human-centered approach to street design, engineered to prevent errors as much as possible and lessen the impacts of errors when they do happen.

We design for all ages and abilities. This includes:

• Designing our streets for people who may not have access to a car
• Designing our streets to protect the most vulnerable road users, like cyclists and pedestrians
• Creating safe and accessible facilities, including bike lanes, that can be used by a wide range of people

Our focus is on moving people and goods, not their vehicles

• Biking and riding transit is a more efficient use of limited street space
• We keep access for trucks and local deliveries, but safely.

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.

• Current street and transportation projects
• Cycling Safety Ordinance-related projects
• City's Five Year Plan for Streets and Sidewalk Reconstruction 
• Map of Cambridge's existing and currently-planned bike facilities, updated in October 2023. This map is for planning purposes and is subject to change - it is not a route map.