Student Voices
Feb. 02 2020

A Counterintuitive Argument Against Bicycle Helmet Laws

New York City mayor Bill DeBlasio recently faced a backlash from bike safety advocates for supporting mandatory helmet laws for the city’s bike-share riders. Advocates arguing with a mayor is nothing new. What’s surprising is their counterintuitive argument: biking advocates, who believe safety is paramount and who typically wear helmets themselves, argue that the helmet requirement actually makes cyclists less safe. And evidence backs up the advocates’ surprising position: helmet laws actively discourage bike-share usage, increase risks to cyclists, and leave opportunities for uneven and discriminatory enforcement. New York currently does not have helmet laws and would not benefit from prioritizing them in bike safety initiatives.

So how could this be? We all know that bike helmets have saved many lives. If you’re cruising along on a road bike at 20 mph, hit a rock, and get thrown forward onto your head, you definitely want a good helmet to absorb the blow. Studies have shown that wearing helmets while cycling reduces the risk of head and brain injuries by about 70 percent, and regular bike commuters should make the decision to wear a helmet, no question. Helmet law proponents argue that these benefits would carry over to bike-share riders, but in fact, the safety picture is more complicated.

Do we need to require that you carry your helmet all day in case you decide to hop on a clunky 40-pound bike-share cruiser to go two blocks from office to lunch? The risk of severe injuries on these short jaunts is low, and in the rare cases where riders are killed, it is most often in devastating collisions with cars and trucks where, as New York City Council Speaker Corey Johnson bluntly put it, “a helmet wouldn’t even help them because of the sheer scope of the accident.” The biggest threat to city cyclists is motor vehicles who don’t see them and don’t respect their space on the road and wearing a helmet is unlikely to mitigate the danger of these bike vs car collisions.


One of the greatest protections bikers have on the road is their sheer safety in numbers, and a helmet law that discourages biking will inadvertently increase the risks to cyclists.

The record shows that mandatory helmet laws for bike-share riders in other cities have failed at their goals. A 2019 University of Washington study showed that 90 percent of Seattle cyclists wore helmets on their own bikes, but only 20 percent wore helmets when using bike shares, despite a county law mandating helmet usage. Even with this low helmet usage, Seattle still sees few bike collisions resulting in head injuries, bringing into question the practicality and need for this type of regulation. Discriminatory enforcement is also a challenge, and a Dallas Morning News review found that helmet laws were enforced more heavily in Dallas’s lower-income communities than in wealthier communities—despite no difference in the share of cyclists wearing helmets. Helmet-related citations were often used as a pretext to stop individuals suspected of more serious drug and weapon charges but were rarely enforced in support of the biker’s safety.

Meanwhile, mandating helmets may lead to law-abiding citizens to avoid taking out bike-share bikes for fear of getting a helmet-related ticket. Riders are likely to forego bikes altogether when facing the barriers of bringing a helmet from home or interacting with a helmet rental system; bike shares that provide helmets have shown lower ridership than those that don’t. While no formal study has been done on the reason for this lower ridership, there is speculation that the inconvenience and yuck factor of interacting with a machine to get a pre-used helmet were enough to discourage riders. Helmet exchanges are also expensive for bike-share companies, who must sanitize and safety check helmets between uses, which limits their financial capacity to add stations and expand their geographic service range widely enough to build ridership. One of the greatest protections bikers have on the road is their sheer safety in numbers, and a helmet law that discourages biking will inadvertently increase the risks to cyclists.

When drivers are accustomed to seeing cyclists, they are more likely to notice them, to check their blind spots, and to be careful when changing lanes and making turns. A 2014 study by the American Journal of Public Health showed the overall rate of injuries among cyclists declined by 28 percent, and head injuries by 14 percent, in cities that added bike shares, regardless of helmet requirements. In its first year, 2013-14, the CitiBike bike-share generated 8.2 million new bike-share trips, while the city’s overall number of cyclists killed and severely injured dropped by 17 percent. Cyclists are much less likely to suffer severe head injuries in areas with marked bike lanes and a regular presence of other cyclists. Thanks to CitiBike and infrastructure improvements, this trend continues today, and adding a mandatory helmet law now could disrupt this progress towards safety in numbers.

There’s no reason to take up an ineffective bike helmet law now when funds and political energy could be more smartly invested towards much-needed infrastructure improvements. Even the National Transportation Safety Board, who generally support helmet laws, stressed that such laws were a small component of an approach that should prioritize “preventing the crash in the first place” through methods like roadway design and collision-prevention technology in cars. New York City Council’s recent vote to invest heavily in an expansion of protected bike lanes, without adding any new helmet requirements, is a step in the right direction and will increase safety more than any helmet law could.


Rebecca Smith is a 2021 MPH degree candidate. She enjoys biking on the Hudson River Greenway (yes, she wears a helmet). She eagerly awaits the expansion of CitiBike into Washington Heights.

If you're interested in submitting to Mailman Student Voices, please send a three-to-five sentence pitch outlining your topic to mailmancomm@columbia.edu.