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06/26/2008 - Study Finds No Increase in Risk between 10th and 11th Hour
The Federal Motor Carrier Safety Administration (FMCSA) recently released a study examining driver safety finding no increase in the risk of accidents between the 10th and 11th hour of driving. The study, “Analysis of Risk as a Function of Driving Hour: Assessment of Driving Hours 1 Through 11,” also found that drivers are most likely to have an accident during the first hour of driving, not the 11th. FMCSA placed the study in the Federal Register on June 25, 2008.
The study was conducted by the Virginia Tech Transportation Institute to assess the relationship between driver safety and driving time. Part of the reason the Court of Appeals rejected the new Hours of Service (HOS) rules introduced in 2004 was because the court felt the rule failed to adequately assess the safety of an additional driving hour and did not address how FMCSA arrived at its decision to extend the driving time. This study in part addresses these concerns and will likely be included in the forthcoming final ruling that is expected to retain the 11th-hour driving time.
The study involved 103 participants and ran for up to 16 weeks. Drivers worked their normal schedules, and their trucks were outfitted with many instruments to record data on the driver and truck. The trucks were also equipped with cameras that recorded the driver as well as the conditions around the truck. Cameras in the front, in the back and on the sides of the truck allowed those conducting the study to determine when the truck driver was at fault. According to the report findings, “drivers are not at an increased risk when driving one extra hour as allowed by the 2004 and 2005 HOS regulations.”
Reported were nine drowsy-related incidents in the 10th hour and seven in the 11th. The study also found 21 drowsy-related incidents in the first driving hour, and the number of incidents decreased as driving time increased.
Because of the limited size of the study, these numbers may not accurately reflect real-life situations. For example, one reason for the fewer number of incidents as the driving hours went up is because drivers might not be driving the full 11 hours, so they had more opportunity to be involved in an accident earlier in the shift. The study also found that drivers were more likely to have a drowsy-related incident between 2 and 3 a.m.
The report also highlighted risk factors for falling asleep at the wheel. They are: an arduous work schedule, poor sleep on the road, daytime sleepiness, symptoms of a sleep disorder, night-time drowsy driving and older, long-time drivers. The study explained that drowsiness occurs naturally in every person. The body functions on a 24-hour circadian rhythm that is based on whether it is light or dark outside (along with other measures, such as body temperature, melatonin levels, etc.). The cycle causes two drowsy lows during a 24-hour period: one during the middle of the night (between approximately midnight and 6 a.m.), and the other occurs between 2 p.m. and 4 p.m. Because of this natural rhythm, drowsiness is something that our bodies are not able to fight. Night-time drowsiness may explain why the hour between 2 and 3 a.m. is more likely to see an accident occur.
The study also suggested that drivers be allowed to take naps during the day that do not count toward the 14 hours of total on-duty time. “Forcing drivers to count naps as part of their workday may actually decrease the chances of a driver taking a nap since drivers are paid by the mile (and not by the hour) and often want to drive as many miles as possible,” the researchers wrote.
There were additional suggestions to improve safety. One was developing a monitor that allows drivers to track their drowsiness level and lets them know when they should stop driving. The study also said drivers find that driving can sometimes be boring, and suggested road signs and billboards. “Signs encouraging drivers to pull over and take a quick nap or get a cup of coffee could also be added…Adding such road signs may help drivers combat boredom and drowsiness while driving on long, monotonous stretches of roadway,” the researchers wrote.
Addressing high-risk drivers was another way to improve safety on the roads. “Companies should provide additional training to potentially high-risk drivers or schedule these drivers during the day so they limit the amount of time that they are on the road during the night when drivers are drowsier.” | 
