The impact of driver distraction in tractor-trailers and motorcoach buses.

Driver distraction has become an increasing concern over the last decade as portable technology has emerged and its presence while driving has become more common. Driver distraction occurs when inattention leads to a delay in recognition of information necessary to accomplish the driving task. Two recent studies were conducted using a naturalistic data collection method and analysis of driver distraction. The Commercial Motor Vehicle Driver Distraction study (Olson et al., 2009) was conducted using heavy truck data, and the Distraction and Drowsiness in Motorcoach Drivers study (Hammond et al., 2016) was conducted using motorcoach data. Data were collected continuously every time the instrumented vehicle was turned on and in motion. Data were reduced to identify safety-critical events such as crashes, near-crashes, crash-relevant conflicts, and unintentional lane deviations. Results show that 40% of truck crashes and 56% of motorcoach crashes had some kind of distracting behavior. Odds ratios were calculated on individual secondary tasks and analyses of variance (ANOVAs) were calculated on eye-glance data to determine the effects of eyes off the forward roadway. Fewer distractions were identified in the motorcoach data, most notably the use of handheld cell phones. This suggests that the 2010 ban on handheld phones has had a positive effect on decreasing cell phone use while driving.

An analysis of driving and working hour on commercial motor vehicle driver safety using naturalistic data collection.

Current hours-of-service (HOS) regulations prescribe limits to commercial motor vehicle (CMV) drivers' operating hours. By using naturalistic-data-collection, researchers were able to assess activities performed in the 14-h workday and the relationship between safety-critical events (SCEs) and driving hours, work hours, and breaks. The data used in the analyses were collected in the Naturalistic Truck Driving Study and included 97 drivers and about 735,000 miles of continuous driving data. An assessment of the drivers' workday determined that, on average, drivers spent 66% of their shift driving, 23% in non-driving work, and 11% resting. Analyses evaluating the relationship between driving hours (i.e., driving only) and SCE risk found a time-on-task effect across hours, with no significant difference in safety outcomes between 11th driving hour and driving hours 8, 9 or 10. Analyses on work hours (i.e., driving in addition to non-driving work) found that risk of being involved in an SCE generally increased as work hours increased. This suggests that time-on-task effects may not be related to driving hours alone, but implies an interaction between driving hours and work hours: if a driver begins the day with several hours of non-driving work, followed by driving that goes deep into the 14-h workday, SCE risk was found to increase. Breaks from driving were found to be beneficial in reducing SCEs (during 1-h window after a break) and were effective in counteracting the negative effects of time-on-task.

Evaluating the 2003 revised hours-of-service regulations for truck drivers: the impact of time-on-task on critical incident risk.

On January 4th, 2004, the Federal Motor Carrier Safety Administration implemented a revised set of regulations concerning the hours-of-service (HOS) of commercial motor vehicle (CMV) drivers. One central component of the revised HOS regulations was a one-hour increase in allowable driving time, from 10 to 11h. The current study evaluated the impact of the additional driving-hour on critical incident risk. Data from a naturalistic truck driving study, which resulted in over 2 million driving miles of continuously collected data, were analyzed. Driving hour bins (hours 1 through 11) were created and the frequency of critical incidents for each hour, and trips (opportunities) per each hour, were identified. A relative frequency was then calculated (critical incidents divided by opportunities) for each hour and odds ratios were determined. Analyses found an elevated risk in the 1st driving-hour, but no consistent significant difference between hours 2 through 11. Analyses on time-of-day, where incident rates were calculated for each of the 24h in the day, were also conducted. The results found a strong positive correlation to national traffic density data. As an impact on U.S. national transportation policy, the results of this study do not support the hypothesis that there is an increased risk resulting from CMV drivers driving in the 11th driving-hour as compared to the 10th driving-hour, or any hour.

The sleep of commercial vehicle drivers under the 2003 hours-of-service regulations.

Previous research has found that commercial drivers get an average of 5.18 h of sleep per night. The revised hours-of-service (HOS) regulations (in the United States) are in place to provide drivers with more opportunities to get sleep. However, are drivers really getting more sleep under these new regulations? Also, is there a relationship between sleep quantity and involvement in critical incident (crashes, near-crashes, or crash-relevant conflicts)? Data from 73 truck drivers, collected during a naturalistic driving study after the implementation of the 2003 HOS regulations, were analyzed to determine overall sleep quantity (using actigraphy), along with sleep quantity prior to being involved in a critical incident. Sixty-two drivers had at least seven consecutive days (Monday through Sunday) of reliable actigraphy data; mean sleep quantity per 24-h period (midnight centered using the Cole-Kripke algorithm) for these drivers was 6.28 h (S.D.=1.42 h). Fifty-eight critical incidents were recorded in the 10th and 11th driving hours. Analysis results indicated that drivers received significantly less sleep in the period prior to a critical incident as compared to their mean overall sleep quantity. The results of this study indicate drivers may be getting more sleep under the revised 2003 HOS regulations as compared to the old regulations. In addition, significantly less sleep in the 24-h period prior to involvement in a critical incident suggests driver fatigue may have been a potential contributing factor in these critical incidents.