The risky business of night driving
Many truck accidents occur when the driver should be curled up in the sleeper cab, a study finds
INEXPERIENCE, driving during the night and a running without basic safety technology are key contributors to heavy vehicle crashes.
That is the verdict of a Victorian study that has controversially observed that obstructive sleep apnoea did not increase the rate of accidents within the group it monitored for the study.
The Monash University Accident Research Centre report (author, Dr Mark Stevenson) was recently published in the American Journal of Epidemiology.
It was a large-scale study, with more than 1000 drivers surveyed for three years in NSW and Western Australia. The average age of those studied was 44, ranging from 21 to 74.
The study group divided about 50-50 on whether thay had been involved in serious crashes. Fatal crashes were not included in the study results.
It may come as no surprise that driving at night can lead to crashes. Truck drivers know only too well the monotony of driving in the dark at a time the human body wants to rest and the difficulty of staying alert, especially on long straight stretches.
Indeed, the MUARC report suggests scheduling changes to avoid midnight-to-dawn driving, along with more frequent rest breaks, could reduce the risk of heavy vehicle crashes by a factor of two or three. That would be a remarkable improvement but the inability to haul freight at night would put a serious strain on the industry to manage moving all the freight that retailers and customers require.
Interestingly, the report also found driving for more than three hours continuously between midnight and dawn could contribute to performance errors equivalent to a blood alcohol concentration of 0.08. The study also found caffeine could help drivers avoid crashes, although Stevenson says consuming too much can have the opposite effect.
The report found that both the use of caffeinated drinks and the time since the start of a trip (when the driver is fresh) were associated with “significantly lower” risks of crashing.
“Drivers who used caffeinated drinks had three times lower odds of crashing and drivers who were in the early stages of the trip were approximately half as likely to crash,” the report says.
Empty trailers pose a substantial risk, according to the study.
It found there was a twofold risk of crashing an empty trailer compared to a loaded one.
Less experienced drivers struggled the most with unladen trailers, which can skip, bounce and slide more easily, although there was still a higher than normal risk of crashes among experienced drivers.
The MUARC study also found that the absence of anti-lock brakes and cruise control ”was strongly associated with the probability of crashing.”
Stevenson says the new findings back a raft of studies on anti-lock brakes that have found they dramatically reduce the risk of crashes. The Australian government has recently announced anti-lock brakes will be mandatory for new trailers from July, although many older trailers without the technology will remain on the roads for some time.
The MUARC study did not “find the presence of objectively measured sleep apnoea to be associated with crash risk among heavy-vehicle drivers”.
Stevenson says this appears to contradict other reports on the effect of the sleeping disorder on drivers but adds that most previous studies did not involve heavy vehicle drivers.
The MUARC study found there was a high prevalence of obstructive sleep apnoea among its sample (compared to the general population) but found there was no link between increased crash rates and those drivers who were found to have the condition.