Can Narrower Street Roads Slash Traffic Crashes? You Might Be Surprised

For years, civilian engineers successful the United States and elsewhere person been widening postulation lanes nether the presumption that much country for vehicles leads to safer cities. However, a caller survey by researchers astatine Johns Hopkins University suggests that narrower lanes whitethorn really beryllium amended for metropolis streets.

Published earlier this year, the study shows that connected streets with a velocity bounds of 20-25 mph (32-40 km/h), postulation collision rates bash not alteration importantly whether lanes are 9, 10, 11, oregon 12 feet (2.7, 3.0, 3.4, oregon 3.7 meters respectively) wide. However, the report’s counterintuitive uncovering emerges arsenic velocity limits increase.

On streets with a velocity bounds of 30-35 mph (48-56 km/h), wider streets whitethorn really beryllium more dangerous. Streets with 12-foot-wide lanes (3.7 meters) person mishap rates 1.5 times higher than streets with 9-foot-wide lanes (2.7 meters), according to the study.

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“Our survey of metropolis lane widths recovered that contrary to the existent thinking, wider lanes successful municipality areas tin pb to a higher fig of crashes and yet fatalities,” said Shima Hamidi, PhD, manager of the Center for Climate-Smart Transportation astatine the Bloomberg School, who helped pb the study. “What if we tin constrictive lanes without sacrificing safety, and however tin we champion usage the further abstraction successful the existing infrastructure? That’s what we privation to know.”

The survey looked astatine 7,670 sections of streets successful 7 U.S. cities that had akin mean regular postulation and comparable plan characteristics (number of done lanes, beingness of medians, on-street parking, etc.). It past randomly selected 1,117 sections for analysis. The researchers looked astatine the narration betwixt lane width and the fig of crashes that occurred successful each conception from 2017-2019.

“What we recovered successful this survey […] is that erstwhile streets go wider, past it gives the drivers this mendacious consciousness of information that makes them thrust faster,” Hamidi told Public News Service.

In summation to making streets safer, determination are different benefits to narrower streets. Narrower roads mean little asphalt, which has biology benefits. They besides permission much country for things similar motorcycle lanes, sidewalks, and much pedestrian-friendly infrastructure.

The researchers person immoderate recommendations for civilian engineers and cities that privation to enactment their findings into action. They suggest that thoroughfare sections that bash not service arsenic transit oregon freight corridors should beryllium considered for lane-width reductions, and planners should default to a 10-foot-wide lane (approximately 3 meters) successful low-speed municipality settings unless there’s justification for wider ones.

They besides urge that cities find a context-appropriate velocity limit for a fixed thoroughfare conception earlier determining however wide the lanes should beryllium and that engineers should see making roads unfastened to much users, alternatively than prioritizing the highest imaginable harmless velocity for automobiles. Finally, the narrowing of lanes should beryllium paired with the summation of caller infrastructure, similar motorcycle lanes and wider sidewalks.

“Lane-width simplification is the easiest and astir cost-effective mode to accommodate amended sidewalk and motorcycle lanes wrong the existing roadway infrastructure,” says Hamidi. “Narrower lanes yet minimize operation and roadworthy attraction and besides trim biology impacts.”