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|Federal Highway Administration > Publications > Public Roads > Vol. 75 · No. 3 > When Distracted Road Users Cross Paths|
Publication Number: FHWA-HRT-12-001
When Distracted Road Users Cross Paths
by Ryan Brumfield and Srinivas S. Pulugurtha
Researchers at UNC Charlotte report on their study of the interaction between inattentive drivers and pedestrians at campus crosswalks.
It can happen to even the most attentive drivers. You're driving along and suddenly you realize you have no recollection of the last few seconds, or even minutes. Maybe you were fiddling with the radio or simply spacing out. Many motorists admit to periodically sacrificing their concentration to attend to something else, whether eating, putting on makeup, rubbernecking, daydreaming, or, increasingly, talking on cell phones or texting.
Psychologists refer to this looked-but-did-not-see phenomenon as inattentional blindness. An article, “Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone,” published in the July 2010 issue of the journal Applied Cognitive Psychology reports on a 2009 study conducted by researchers at Western Washington University that demonstrated the legitimacy of this theory for pedestrians as well. The researchers discovered that pedestrians on the college campus were less likely to notice an unusual activity—in this case, a clown riding a unicycle—if they were distracted by a cell phone. Even if they looked right at the clown, they failed to see the unicycle or the rider because their attention was focused on the phone conversation.
The same thing can happen to drivers when distracted. The nondriving task gets stored in the driver's memory, while the events relevant to driving may go unnoticed or are omitted from memory storage. According to the university researchers, “when driving a car while talking on a cell phone, people may be unaware of what they are missing until it is too late.”
According to data from the National Highway Traffic Safety Administration (NHTSA), in 2009 nearly 5,500 people were killed and 450,000 injured in crashes that were reported to have involved distractions. The problem has received widespread media coverage in recent years, as U.S. Transportation Secretary Ray LaHood has taken to the airwaves and the Internet at www.distraction.gov to raise awareness of the dangers of inattentive driving. “Distracted driving is a serious, life-threatening epidemic that steals loved ones from us and puts responsible drivers in danger every time they hit the road,” says LaHood.
A recent study, “Effect of Road User Distractions on Pedestrian Safety at Mid-Block Crosswalks on a College Campus,” conducted by researchers at the University of North Carolina at Charlotte (UNC Charlotte) looked at the role of distraction—both among drivers and pedestrians—in yielding behaviors at crosswalks on the college campus. The results point to even greater dangers when motorists and pedestrians lose their focus in the roadway environment.
Pedestrians Are Vulnerable
Unexpected events such as a pedestrian crossing the street can catch a distracted driver unaware, leaving little time to react and take evasive action. Inattentive pedestrians exhibit a similar lack of awareness to respond to sudden conflicts or unexpected obstacles. Take, for example, the teenage girl in New York City who, in July 2009, fell into an open manhole while texting and walking on a sidewalk in Staten Island. Fortunately, she survived without serious injury. However, pedestrians exhibiting this level of obliviousness while crossing a street put themselves at the mercy of drivers who themselves may or may not be paying attention, as was the case in Salem, OR, earlier this year when a teen who was texting while driving struck and killed a pedestrian.
“Ultimately, crosswalk safety often depends on the attention level of road users when they interact with one another,” says Beth Alicandri, director of the Office of Safety Programs at the Federal Highway Administration (FHWA). “Without sufficient concentration, drivers and pedestrians are ill-prepared to react to conflicts in the road environment.”
UNC Charlotte Study
When drivers experience inattentional blindness and fail to notice certain details of their commutes, what mistakes could they be making without even realizing it? Maybe they unknowingly run red lights or pull out in front of other cars. Maybe they drift over the centerline or forget to use their turn signals. Maybe they drive slowly in the passing lane. Or, as a recent study from UNC Charlotte suggests, they might fail to yield to pedestrians at crosswalks.
Researchers at UNC Charlotte observed the behaviors of drivers and pedestrians at seven midblock crosswalks on the university campus. The intent was to investigate the yielding patterns of road users to determine if distracted drivers and pedestrians behave differently than their attentive counterparts. The researchers hypothesized that distracted drivers and pedestrians are unaware of their surroundings and therefore unlikely to notice and stop for other road users.
Each of the observed locations had crosswalk striping, although not highly visible in some cases. Several of the study sites included advance signage notifying drivers of the crossing area. The campus-wide speed limit at UNC Charlotte is 20 miles per hour (32 kilometers per hour).
For each location, researchers observed and recorded driver and pedestrian yielding behaviors, along with information regarding road user distractions. The researchers separated distractions into three categories: talking on a cell phone, texting, or other. The “other” category included distractions such as eating, listening to a portable music player, putting on makeup, reaching for something, talking to a passenger, or anything else that had an obvious effect on road user attention.
The researchers collected data only for road users who had an opportunity to yield. That is, data on drivers and pedestrians who passed through without interacting with another road user were not recorded. In cases where multiple pedestrians crossed at the same time, the researchers only collected data for the first pedestrian in the group.
The researchers also noted vehicle-pedestrian conflicts during the data collection. They recorded six types of conflicts, each describing a situation when either the pedestrian or vehicle had to change paths or speed of travel abruptly to avoid collision with the other road user. For example, the most commonly noted conflict was a pedestrian entering the crosswalk and then stepping back because the vehicle did not yield. Upon completion of data collection, the researchers compiled and analyzed the results for statistical significance.
The results of the UNC Charlotte study show that overall about 64 percent of drivers yielded to pedestrians, and about 20 percent of pedestrian-vehicle interactions resulted in conflicts. One location experienced driver yield percentages as high as 76 percent, while another location had yield percentages as low as 46 percent. Likewise, the chance of conflict varied from 11 percent to 29 percent, depending on the location. These variations may be attributable to differences in crosswalk visibility, signage, and, of course, driver and pedestrian behavior.
Although results varied by location, on average, about 18 percent of drivers and 29 percent of pedestrians were noticeably distracted as they traversed the crosswalks. Approximately 9 percent of drivers (50 percent of distracted drivers) were talking on a cell phone, and 3 percent of drivers (15 percent of distracted drivers) were texting. About 16 percent of pedestrians (54 percent of distracted pedestrians) were talking on a cell phone and 7 percent (23 percent of distracted pedestrians) were texting.
When compared to attentive drivers (drivers not partaking in a nondriving task), distracted drivers were about 15 times less likely to yield to pedestrians (77 percent compared to 5 percent) and about 4 times more likely to be involved in conflicts with pedestrians (51 percent compared to 13 percent). These results provide strong evidence that distracted drivers have poor yielding behavior compared to seemingly attentive drivers.
In contrast to the findings regarding distracted drivers, the data show that the chance of conflict was essentially the same for distracted and attentive pedestrians (21 percent versus 17 percent). Although this result implies that pedestrians can maintain safe crossing behavior while inattentive, in reality, the conflict potential is constant because drivers yield at a much higher rate when distracted pedestrians are present. In fact, results show that drivers were about 40 percent more likely to yield to distracted pedestrians than to those who were attentive. The researchers observed distracted pedestrians making aggressive crossing maneuvers, failing to make eye contact with approaching drivers, and darting in front of traffic. These behaviors support the notion that distracted pedestrians are more careless, obliging drivers to stop abruptly to avoid conflicts.
Although the study findings did not show a direct correlation between road user distraction and crash risk, the researchers believe that yielding behavior at a particular crosswalk is an indicator of the relative safety at that location. The greater the driver yield rate, the lower the chance of conflict with a pedestrian and, thus, the lower the crash risk. As the results from this analysis imply, if a high percentage of road users—motorists and pedestrians—are distracted, conflict potential will tend to be greater and, therefore, crash risks will be higher.
1 Percent distracted includes percent talking on a cell phone and percent texting.
Source: UNC Charlotte.
1 Percent distracted includes percent talking on a cell phone and percent texting.
Source: UNC Charlotte.
Countermeasures To Increase Yield Rates
In tandem with the efforts of NHTSA and other organizations to curb distracted driving, highway agencies can use infrastructure solutions to make the road environment less complex so drivers with limited attention are still able to process critical information. For example, crosswalk treatments that stand out, such as high-visibility lighting, striping, and signing, may increase the likelihood that distracted drivers will notice pedestrians and safely yield to them.
“We hope that countermeasures that can grab the attention of drivers, especially those who are distracted, can lead to better yielding behavior and decreased likelihood of pedestrian-vehicle conflicts,” says Tamara Redmon, manager of FHWA's Pedestrian Safety Program. “Treatments that improve crosswalk visibility and make pedestrians more conspicuous may offer safety benefits.”
FHWA has verified the safety effectiveness of numerous countermeasures for use at midblock crosswalks. For instance, in areas where crossings occur at nondesignated midblock locations, simple striping and signing can make drivers aware of the presence of a pedestrian crossing zone. Installation of transverse markings, bar pair markings, or continental markings can alert drivers of possible pedestrian activity. Proper signage can help drivers recognize crossing areas and reinforce State laws that require yielding to pedestrians. In all cases, it is important that traffic control devices be in compliance with the national standards outlined in the Manual on Uniform Traffic Control Devices (MUTCD) so road users from all areas of the country can instantaneously recognize and comply with their messages.
When pedestrians must cross multiple lanes of travel, median refuge islands provide safe places for them to stand while waiting for a gap in the traffic stream. In areas where visibility is poor, installing overhead street lighting or in-pavement warning lights can help drivers recognize potential conflicts. For corridors with heavy pedestrian activity, agencies might consider installing midblock stop signs, traffic signals, or pedestrian hybrid beacons to create breaks in traffic for pedestrians to cross safely. Other proven midblock treatments include dynamic lighting (increased illumination of a crosswalk when a pedestrian is present), Danish offset islands (median refuge islands with offset entry and exit points), automated pedestrian detection, flashing beacons, in-pavement text, pedestrian countdown timers at signalized crossing areas, and advance stop lines near crosswalks.
Of course, safety problems differ by location, and highway agencies need to determine the most effective and appropriate solutions on a case-by-case basis. The FHWA Office of Safety and its partners have developed numerous online tools, publications, and guidance materials to help practitioners assess pedestrian safety problems and choose suitable treatments to reduce the likelihood and severity of crashes. (See “Selected Pedestrian Safety Resources” on this page.)
Distracted drivers and pedestrians, whether on a highway, at an intersection, or in a crosswalk, pose a threat to themselves and others. As shown in this study, distraction reduces the likelihood that a driver will yield to pedestrians in a crosswalk. Due to this increased failure to yield, it is likely that crash risk is higher for pedestrian-vehicle interactions involving a distracted driver. Further, when the observed pedestrians were distracted, they tended to cross the road in an aggressive manner, oblivious to approaching vehicles, which also had a negative effect on crosswalk safety. Ultimately, a safe roadway environment depends on all road users paying attention to where they are going and being aware of other users who might be sharing the road.
Ryan Brumfield is a civil engineer in FHWA's Arkansas Division Office. He is currently a participant in the agency's Professional Development Program, a 2-year training program for new employees. He recently graduated from UNC Charlotte with a master's degree in civil engineering.
Srinivas S. Pulugurtha is an associate professor in the Department of Civil and Environmental Engineering at UNC Charlotte, where he teaches graduate and undergraduate courses and conducts research in the areas of traffic safety, geographic information systems applications, and transportation planning and modeling.
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