Cambridge, Massachusetts: When a City Makes Bike Lanes the Law

While some cities are tearing out bike lanes, Cambridge, Massachusetts has done the opposite: it wrote protected bike lanes into law and then defended that law in court… twice. The result is one of the strongest legal commitments to safe cycling infrastructure in North America, plus a very loud local argument about parking, process, and what city streets are for.

The Cycling Safety Ordinance in a nutshell

In 2019, Cambridge’s City Council passed the Cycling Safety Ordinance (CSO), requiring that when key streets are rebuilt, they must include separated bike lanes where the city’s Bicycle Plan calls for them. In 2020 the Council amended the law to go further: roughly 25 miles of separated bike lanes must be installed between 2020 and 2027, with specific corridors spelled out in the ordinance (all of Massachusetts Ave, plus major segments of Broadway, Cambridge St, Hampshire St and Garden St, plus another 11.6 miles elsewhere in the network).¹ In 2024 the deadline was extended slightly to November 1, 2026 for most of the “quick-build” projects.¹

This isn’t just a policy preference; it’s a statutory obligation. Staff are legally required to redesign streets for separated bike lanes on those corridors, and to find ways to make the details work around buses, loading, and parking.

As of May 2024, the city reports that 13.77 of the 25 required miles of separated lanes had already been installed or were under construction—more mileage than Cambridge added in the previous seven years combined before the ordinance existed.²

A quick look at the rollout

Cambridge’s own summary breaks down the first four years of CSO implementation like this:²

That work includes major projects on Brattle Street, Hampshire Street, Mt. Auburn Street, and around Inman Square, with more coming to Cambridge Street, Broadway, and Main Street.²

The backlash: parking, process, and small businesses

The drama starts where the paint hits the curb.

On segments of Massachusetts Ave and elsewhere, protected bike lanes replaced large amount of on-street parking. Some long-time businesses say their revenues dropped because customers can’t find spots, and they’ve been very vocal about feeling blindsided by the rollout.³⁴⁵

Local TV news has repeatedly highlighted shop owners who claim 40–70% revenue declines after parking removal, especially in North Cambridge, and some councillors sympathetic to businesses pushed for slower timelines or design changes.³⁵ In response, the city:

• Reintroduced some parking in limited windows (for example, allowing parking in a bus lane at off-peak times).³
• Created a formal Cycling Safety Ordinance Advisory Group in 2023 to advise on communication, outreach, and evaluation.⁶
• Commissioned an economic impact study to look at actual employment, rent, and vacancy data along bike-lane corridors.⁷

So you have a familiar pattern: vocal localized anger over parking and process, alongside city staff trying to retrofit better engagement onto a mandate that is already legally locked in.

The lawsuits (and why Cambridge keeps winning)

Two different lawsuits attempted to stop or roll back the CSO projects:

• Cambridge Streets for All (CSFA) sued in 2022, arguing that building 25 miles of protected bike lanes was an improper use of taxpayer money and illegally removed parking and access. A Middlesex Superior Court judge dismissed the case in March 2023, ruling that the city has authority to install bike lanes as part of its traffic management powers.⁸
• A second case, Aster et al. v. City of Cambridge, tried a different angle: claiming the bike lanes were an illegal change to the city’s “traffic rules and regulations.” In February 2024, the same court dismissed that suit as well, explicitly finding that bike lanes and their signs/markings are traffic control devices, not “rules and regulations” in the legal sense.⁹¹⁰

The key legal takeaway: in Massachusetts, at least according to these rulings, cities can stripe and reconfigure lanes for bikes and buses without treating that as a change to fundamental traffic “rules.” That gives Cambridge—and by precedent, other municipalities—a lot of room to keep building protected networks even in the face of organized opposition.

What the numbers say so far

Mode share and ridership are up

Cambridge’s own data show that biking is increasingly normal:

• As of 2024, about 9% of Cambridge residents bike to work, and 9.5% of commuters to Kendall Square go by bike, the highest on record.²
• Bluebikes bike-share trips in Cambridge reached their highest counts in 2022 and remain strong, indicating that biking isn’t just a commute phenomenon but happens throughout the day.²

A detailed before–after study on Garden Street by the Boston Cyclists Union’s BCU Labs found that, within four months of converting a half-mile segment to fully separated lanes:

• Local bike mode share on nearby residential streets increased by about 300%.
• Observed bike volumes rose by more than 500% in the surrounding area.
• Bluebikes ridership in the vicinity also spiked, suggesting people were newly willing to ride because the route finally felt safe.¹¹

That study also documented residents who literally bought bikes because of the new lanes, reinforcing the idea of “latent demand” unlocked by safer infrastructure.¹¹

Safety and crashes

Cambridge Bicycle Safety’s summary of crash research notes that, based on Federal Highway Administration work and city analysis, separated bike lanes can cut crash rates by up to 50% and significantly reduce the severity of injuries when collisions do occur.⁷ That aligns with international evidence: when you physically separate bikes from car traffic, fewer people get hurt and those who do are less likely to be seriously injured.

Economic impact: noisy complaints, quiet data

The city-commissioned CSO Economic Impact Study looked at three objective indicators on streets with recent bike-lane projects:

• Employment trends
• Commercial rents
• Commercial vacancies

Its conclusion: there were no meaningful differences between streets with new separated bike lanes and comparable “control” corridors without them.⁷ Businesses certainly reported anxiety and blame bike lanes for downturns, but the data didn’t show systemic economic harm.

Advocates have pointed out that this matches patterns seen in places like New York, Toronto, and Berlin—where business owners often predict disaster before projects, but sales tax and rent data later show little to no negative effect and sometimes modest gains.⁷

Outside ratings

From the outside, Cambridge looks less like a place “at war over bikes” and more like a national proof-of-concept. PeopleForBikes rated Cambridge #2 out of 604 medium-sized U.S. cities for bicycling in its 2024 rankings, highlighting the CSO and the city’s long-running efforts to reduce car dependence and lower speed limits.¹²

What makes Cambridge different in the “bike lane wars”?

Lots of cities have bike-lane drama. Cambridge’s difference is that it treated safe cycling not as a pilot or a mayor’s initiative, but as law backed by metrics:

• The goal is explicit and measurable: build about 25 miles of separated lanes on specified corridors by a set date.
• Progress is tracked publicly (down to yearly mileage added).
• Backlash has been intense, particularly over parking and process, but the city has responded by adding advisory structures and economic analysis rather than dismantling the network.
• Courts have affirmed the city’s authority to change street layouts, undercutting the most aggressive legal challenges.

That doesn’t mean Cambridge has handled everything perfectly, communication missteps and real business anxieties are very much part of the story. But compared to places where higher levels of government are now ordering bike-lane removals, Cambridge shows what it looks like when a city doubles down, measures the results, and keeps going.

If Toronto is a case study in how higher-level politics can yank a city backward, Cambridge is almost the mirror image: a small city using its legal tools and data to lock in a safer, more bike-centric future and then defending that choice in court.