Center for the Advancement of Health: Not Clear That Visibility Reduces Injuries to Pedestrians, Cyclists – 6 November, 2006

While flashlights, luminescent tape and other visibility aids work well to make pedestrians and cyclists more conspicuous, it is not clear that increased visibility translates to fewer roadside crashes or traffic injuries, according to a new survey of road-safety research. “We set out to understand if these visibility aids stopped people from getting hurt, prevented them from getting knocked down by cars, but none of the studies we found measured that outcome,” said lead reviewer Irene Kwan.

Kwan’s review turned up 39 studies testing different kinds of visibility aids including joggers’ vests, reflective bands, blinking bike lights and biomotion clothing. But none of the studies was designed to test if visibility aids reduce traffic injuries.

“So we know the time it took for a driver to distinguish a person in the roadway, but what we don’t know is if that was enough time for them to stop and avoid a collision,” she said.

All the studies reported on drivers’ responses to the visibility devices. For instance, one study measured the time it took for drivers to detect a cardboard dummy outfitted in a fluorescent lime-green vest. Another study gauged the distance before drivers noticed a bicyclist equipped with lamps or bike reflectors.

The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates research in all aspects of health care. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing trials on a topic.

Kwan says combined evidence suggests that visibility aids can make pedestrians and cyclists stand out from the scenery. But she said she’d like to see more research on whether joggers and walkers are willing to use the devices and data collection of road injuries involving pedestrians and cyclists wearing visibility aids. Nor is there sufficient research on the best ways to educate road users about traffic injury prevention, she said.

“A lot of people are encouraged to ride their bike or walk to work for their environmental and health benefit. But while people are doing that there must be some public measure to protect them,” Kwan said.

“It’s an area where an awful lot of people are dying unnecessarily. In my mind, that makes it a public health concern,” said transportation safety researcher Richard Tyrell, who was not involved in the review.

Tyrell’s investigations reveal that pedestrians dramatically overestimate their own visibility. “If a pedestrian feels very conspicuous, then they are likely to engage in more risky behaviors. They are likely to feel comfortable jogging along the side of the road thinking that drivers can see them from a great distance, failing to understand they are in danger,” said Tyrell, a psychology professor at Clemson University.

That false sense of safety also means pedestrians and cyclist are less likely to use visibility aids, Tyrell said. A variety of these aids are readily available, but Tyrell believes that the most effective is a technique that uses reflective material to call attention to the body’s motion.

“If you can outline the major joints of the body, as soon as that person moves, a driver is quick to detect that there’s a stimulus, but also recognize that stimulus is a person,” he said.

Tyrell says it’s an inexpensive and easy fix to improve nighttime visibility. “Anybody can go to Wal-Mart and buy reflective tape and apply that themselves to their ankles, wrists,” and other joints, he said.

FOR MORE INFORMATION:
Health Behavior News Service: (202) 387-2829 or www.hbns.org

Kwan I, Mapstone J. Interventions for increasing pedestrian and cyclist visibility for the prevention of death and injuries. Cochrane Database of Systematic Reviews 2006, Issue 4.

The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
Center for the Advancement of Health
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