As a proposal to lower Chicago’s default speed limit stagnates in the City Council, the city is falling further behind other major cities that have long had lower limits in place, with improved safety.

For at least a decade, cities from coast to coast have been lowering speed limits to 25 or 20 miles per hour — starting with New York City, which made the sweeping move in 2014 and is now weighing whether to push further.

In Chicago, though, council members are debating the safety benefits of lowering the speed limit from 30 to 25 miles per hour versus the economic impacts on drivers. The measure passed out of committee in October but has been held from a vote from the full City Council while proponents whip support.

Some cities have rolled out their lower limits gradually, others all at once. Some tied their policies with other tools to slow traffic, like speed cameras or curb extensions. Others simply changed the signs and watched what happened.

In every case, city leaders pointed to tangible safety improvements, including clear reductions in speeding, decreases in traffic deaths — or, in many cases, both.

In Chicago, traffic crashes killed 136 people in 2023, according to the city’s Department of Transportation. That’s nearly twice as many road deaths per capita than New York City saw over the same period, but fewer than Los Angeles or Houston.

The Chicago proposal, sponsored by Ald. Daniel La Spata (1st), would set a maximum speed limit of 25 miles per hour on city streets and 15 miles per hour in alleys. It would take effect in January 2026. 

City transportation officials have estimated that the change could cost the city up to $2.5 million for 10,000 new speed limit signs, which would be needed to promote the lower limit because Illinois statute sets a default 30 mile-per-hour speed limit unless otherwise marked. If the state changed the statute or lowered the limit, the cost to the city could be significantly less, officials said.

The Chicago Department of Transportation supports the move, according to a draft traffic study the department has circulated that was obtained by Illinois Answers Project.

“Comprehensively enacting a 25 mph speed limit is a reasonable and safe approach to improving traffic safety across Chicago,” transportation department officials wrote in the document. “Case studies from peer cities across the U.S. show that reducing speed limits has a positive impact on driving behavior and results in safer roadways.”

Still, the measure has drawn detractors within the City Council who worry additional speeding fines would hit hardest those least able to pay, including many drivers of color. Some argued speed limits should be lowered incrementally in different parts of the city instead of all at once.

“Communities have different challenges, and I think this one-size-fits-all approach is not necessarily in the best interest of all Chicagoans,” said Ald. Jason Ervin (28th), who voted against the proposal in committee.

Local leaders in other cities have implemented the changes across the board and have not looked back.

New York City

When the New York City Council voted in October 2014 to lower the city’s default speed limit from 30 to 25 miles per hour, it represented a sudden and widespread shift across the city of 8 million. Before the switch, the 30 mile per hour limit applied to about 95% of the city’s streets. Overnight, the limit decreased almost everywhere.

Part of a larger package of new policies designed to reduce roadway crashes, the plan involved the installation of about 3,000 new speed limit signs during the course of a year at a cost of around $500,000.

Almost immediately, the city registered a drop in fatal crashes.

The New York Department of Transportation logged 243 traffic deaths in 2015, down from 297 in 2013, an approximately 18% drop. Pedestrian deaths in particular fell by nearly 24% in the same period.

A New York-based advocacy group, Transportation Alternatives, which tracks traffic deaths independently, found an even sharper drop in deaths after the 2014 speed limit change. Now, the group is pushing for a further reduction of the speed limit to 20 miles per hour on most roads.

“Twenty-five miles per hour was kind of an intermediary step, trying to get people a little more comfortable with it,” said Alexa Sledge, a spokesperson for Transportation Alternatives. “Making sure cars are going slower, especially in neighborhoods where there’s tons of children, is going to be really, really, really critical, because if a car is going … 20 miles per hour, it’s just so much safer for everyone in that car and around that car.”

The city, which has traditionally relied on police to enforce traffic laws, launched a pilot program in 2013 to place speed cameras near school zones. By 2022, when 2,000 cameras were in operation across 750 school zones, the city’s department of transportation reported a 73% drop in speeding near the cameras’ locations.

Unlike Chicago’s speed cameras, which fine drivers $35 for exceeding the speed limit by between 6 and 10 miles per hour, New York’s cameras only ticket people driving more than 10 miles per hour over the limit but issue $50 tickets for every offense. New York City’s transportation department found that nearly half of drivers who racked up speeding tickets between 2014 and 2022 did not receive a second violation, and an additional 19% of speeders never received a third ticket.

Seattle

At the urging of local transportation officials, the Seattle City Council voted in 2016 to lower the default speed limit on unmarked roads to 25 miles per hour on arterial streets and 20 miles per hour on local roads. Unlike New York, Seattle officials implemented the change gradually.

Officials added signs to lower speed limits one neighborhood at a time, often accompanied by speed humps and narrowed roads, finally following up with a 2019 policy implementing the lower limit across the city. The city put the policy into effect by installing 2,500 new speed limit signs during 2020 and 2021, at a cost of about $500 per sign.

Also unlike New York or Chicago, Seattle did not pair the lower limits with any new enforcement. Still, they credited the change for saving lives.

A study published February in the Journal of Safety Research found about a 20% reduction in downtown traffic crashes and a 17% reduction in crashes involving injury following the implementation of lower speed limits.

To study the effects of lowering the speed limit in isolation, the Seattle Department of Transportation tracked a stretch of arterial road in which they posted a lower speed limit but “intentionally did not advertise the changes with a communications campaign, retime traffic signals, increase enforcement or make any other engineering adjustments to the street design,” according to a department spokesperson.

Crashes dropped by 20%, and the number of drivers who drove 40 miles per hour or faster decreased by more than half. 

“It kind of shows that when people are driving down the street and they see a speed limit sign almost every 30 seconds … it creates this consistent reminder,” said James Le, a senior civil engineer with Seattle’s transportation department.

Citywide traffic deaths still ticked up in 2021, “mirroring national trends” amid the COVID-19 pandemic, according to a department spokesperson

Boston

Boston lowered its citywide speed limit from 30 to 25 miles per hour in January 2017 following a vote by its City Council as part of a broader package to improve roadway safety.

The Boston Department of Transportation did not respond to a request for comment or information about the change. However, a review of public crash data published by the city shows a nearly 22% reduction in crashes from 2017 to 2023.

Two years after Boston lowered its speed limit, the Insurance Institute for Highway Safety published a study that found only a slight drop in overall speeds — but sharp reductions in people driving over the limit, with the biggest drops in people driving 35 miles per hour or more.

Wen Hu, a co-author of the study and a senior research transportation engineer at the institute, has not directly advocated for lower speed limits, she said. But she offered up her research as a guidepost for policymakers across the country. 

“We hope that our research could help the lawmakers, the local leaders, to provide them some real-world evidence on the effects of lowering the speed limit,” Hu said. “Hopefully, this could urge them to make the change.”

Hu also conducted the 2024 Journal of Safety Research study that tied a reduction in crashes to lowered speed limits in Seattle. Hu said the evidence is clear for the effectiveness of lowering speed limits — especially if it’s accompanied by infrastructure upgrades and tighter enforcement, she said.

“Enforcement strategies such as speed safety cameras would help boost the drivers to follow the speed limit,” Hu said. “And some engineering treatments … could help reduce the speed. They’re all important.”

Portland

Portland, Ore., lowered the speed limit on all the city’s residential streets to 20 miles per hour in 2018, and the city’s Bureau of Transportation reinforced the change by installing 1,000 new speed limits signs and distributing 7,000 “20 is plenty” yard signs for homeowners to put in their front yards.

A 2020 study conducted by Portland State University found a slight overall reduction in speeds on residential streets after the lower speed limits went into effect, but drivers were about 34% less likely to exceed 30 miles per hour and 50% less likely to drive more than 35 miles per hour after the new signs went up.

“It is most noteworthy that the reduction in the percentage of vehicles faster than 30 mi/hr and 35 mi/hr are larger in magnitude than the other changes,” researchers wrote.

The change did not prevent a sharp jump in citywide traffic deaths, which nearly doubled from 35 in 2018 to 69 last year, according to the Portland Bureau of Transportation. 

However, nearly three-in-four of Portland’s traffic deaths in 2023 were linked to crashes on highways or arterial streets of four lanes or more — not the residential streets where speed limits were lowered, according to the bureau’s most recent annual report.

Transportation officials blamed the COVID-19 pandemic for the citywide spike in traffic deaths during the last five years, writing in their report that “the social challenges that were exacerbated during the pandemic … continue to play out on our streets.”

San Francisco

Multiple cities in California have moved to lower speed limits since a 2021 law went into effect allowing local control. They included San Francisco, where officials in 2022 identified 79 stretches of high-traffic roadways and has since lowered speed limits from 25 to 20 miles per hour.

A study conducted by the San Francisco Municipal Transportation Agency in 2023 found a 16% year-over-year reduction in collisions on streets where the speed limit was lowered, and a 35% reduction in collisions involving pedestrians. It also recorded a 33% increase in the volume of cyclists using the roads during the same period.

“I think it’s been well received,” San Francisco traffic engineer Ricardo Olea said of the change. “We’ve done campaigns to make people aware that this is a new way to drive on these streets — trying to do a mindset change where people are driving much differently.”

San Francisco did not pair the lower speed limits with any new enforcement but is now developing a speed-camera program, Olea said.

It cost the city about $400,000 to change the signs on 23 streets last year, officials said.

Los Angeles

Following a vote by the Los Angeles City Council in 2022, the city is gradually lowering the speed limit by 5 miles per hour on more than 177 miles of its streets this year.

“By reducing speed limits we protect the most vulnerable pedestrians, bikers, seniors, and children by giving drivers and others more time to react to prevent a collision,” according to the department of transportation. 

The city began lowering speed limits on its streets earlier this year.

The city’s transportation department estimated it would cost $52,282 for new signs.