Anti Sleep Alarm
Driver fatigue is a particular problem for truck drivers. A 1998 American study found that about 20% of all fatal crashes and fatalities and 10% of all injuries involving a long-haul truck, occurred between midnight and 6 a.m, the peak period for driver fatigue. These crashes tended to be more severe than crashes during other parts of the day. Truck driver fatigue was a particular problem in single-vehicle fatal crashes, but in crashes involving other vehicles, fatigue was coded more often for the other driver than for the truck driver.
In another study, 593 truck drivers were interviewed at rest areas on New York's interstate highways29. Nearly two-thirds reported episodes of drowsy driving within the previous month, and almost 5% said that they drove when drowsy on most, if not all, days. Nearly half had fallen asleep at the wheel at some point in their driving career, and about one-quarter reported doing so at least once during the previous year.
Truck driver fatigue may be a contributing factor in as many as 30% to 40% of all heavy truck accidents.
For a two year period large truck crashes on the interstate system in Washington State were investigated using a case-control method31. For each large truck involved in a crash, three trucks were randomly selected for inspection at the same time and place as the crash. Driving in excess of eight hours increased the risk of crash involvement by a factor of two; drivers with log book violations, young drivers, and interstate drivers also had increased crash risks.
Similar evidence in relation to those who operate and/or manage other modes of transport, such as trains, ferries and aircraft indicates a correlation with the research into trucks and driving.
In most countries, HGV and PSV drivers are subject to regulations that set limits on the amount of time they can drive without a break, the amount of time they can drive in a day, the amount of time they can be on-duty and for minimum rest periods. These regulations are designed to prevent drivers from driving for unreasonably long periods and consequently falling asleep at the wheel. However, they still allow drivers to drive for very long periods (E.U. Drivers Hours Rules, for instance, allow drivers to drive up to 4.5 hours without a break, and even this can be extended).
Driver Hours regulations are flawed in other respects. In America, they have been criticised for actually increasing risk because they do not take account of circadian rhythms and so sometimes require a driver to rest when wide awake, and to drive when sleepy.32 Horne25 points out that the EU Drivers Hours do not appear to be based on any evidence of safe driving times.
One of the studies by Horne found that all of the sleep related HGV accidents occurred within two hours of the start of the journey. An analysis of more than one thousand commercial vehicles in Europe found that most truck accidents take place in the first seven hours of the driving time.
Discussions are underway in the EU on the possibility of extending the Working Time Directive (which sets limits on the amount of working, as opposed to driving, time) to cover drivers and operators who are currently covered by the Drivers Hours Rules. In its Road Safety Strategy, the British Government states that once the results of the EU discussions are known, it
will consult on repealing the UK Domestic Drivers Hours Rules in favour of the EU Rules.
Even the limits set by the Drivers Hours Regulations are often flouted by operators and drivers. And many classes of drivers are not covered by these regulations. Van, taxi and company car drivers do not have legal limits on their driving time. An Australian survey showed that about 38% of truck drivers exceeded 14 hours of driving in a work day, and another 5%
exceeded 14 hours of work (including non-driving work). About 5% of drivers reported having not slept and 7.5% reported less than four hours of sleep on at least one work day of the preceding seven days. Overall, about one third of drivers obtained less than six hours of sleep on at least one working day.
In America, almost 20% of drivers reported that they "always or often" exceeded the 10-hour driving limit in the Federal Highway Administration Hours-of-Service (HOS) regulations. Close to one-fifth were usually off-duty for fewer than eight hours, and just over 21% drove longer than their records indicated.
Another study found significantly higher fatigue accident rates for drivers who drove for longer than 9.5 hours per day without rest, for driving at night, and for driving in remote areas. These factors were found to have a cumulative effect on fatigue-related truck accident rates.
A New Zealand study36 compared a group of heavy vehicles involved in crashes (for which details of drivers' hours were known from their log-books) with a matched control group of similar vehicles. There was an increased crash risk when driving hours since the driver's last compulsory 10 hour offduty period exceeded about eight hours.
The Australian study referred to above (5.2.5)34 found that 67% of truck drivers with irregular schedules had been involved in fatigue-related accidents, compared to 38% of drivers with regular schedules. 82% of the drivers who admitted to having exceeded the number of permissible driving hours had had a fatigue-related accident. The most important measures in
predicting a fatigue-related accident in the sample were the duration of the last sleep period, the total hours of sleep obtained during the 24 hours prior to the accident, and the split sleep patterns.
A study of schedules of 498 long-distance drivers found that, assuming average legal speed limits of 55 mph, 26% of the drivers had schedules that required them to exceed speed limits in order to meet the schedule. Assuming average travelling speeds of 50 mph, the vast majority of long distance drivers would have to work more than 40 hours a week, half would work more than 65 hours and a quarter over 81 hours a week.
An informal truck driver ‘Pooling’ system is known to operate in UK, in which (usually self-employed) drivers are ‘called-off’ by large operators as and when required. It is understood that this enables individual drivers to work far longer than would be legally possible if they were employed by a single employer. Such practice, while obviously attractive to commercial operators because it enables them to pay only for the hours or trips they need, leaves much to be desired in safety terms, since the drivers may well have already worked a full quota of hours for other companies before they start the next job.
Shift workers are more likely to have less sleep, and sleep disturbances, than non shift workers. Disruptions to the circadian rhythm are associated with impaired attention and performance and slower reaction times.
An investigation of the rate of road accidents related to sleep duration in 448 shift nurses found that road accidents occurred more frequently on the way home from morning and night shifts. Those nurses who reported accidents generally slept less than their colleagues. Another study compared nurses on rotating shifts with nurses on other schedules and found that
those on rotating shifts reported more accidents (including driving accidents).
A USA survey39 of rotating shift and straight day workers at a manufacturing plant found an increased incidence of motor vehicle accidents or 'near misses' in which sleepiness was cited as a cause: 22% of rotating shift workers compared to 7% of day-only workers. Complaints of poor sleep and increased sleepiness during hours of wakefulness were also significantly more common in shiftworkers than day workers. Shiftworkers reported higher caffeine and alcohol consumption, and were more likely to use alcohol as a sleep aid.
Another study40 found that there were few differences in alertness during work hours, but that 12 hour shift workers were significantly more sleepy at the end of the shift, especially at 7:00 am., than eight hour shift workers. Such workers were particularly at risk when driving home after their shift.
Passenger Carrying Vehicles
Taxi and private hire car drivers also often work very long hours, although they are more likely to drive in urban environments where the risk of falling asleep at the wheel is less. However, they often work shifts, and in the early hours of the morning which increases their risk.
An Australian study41 examined fatigue-related variables and their relationship with accident involvement in a group of 42 Sydney metropolitan taxi drivers over a two-year period. The authors found that driver time-on-theroad is often considerable: 67% of those surveyed drove at least 50 hours per week, yet time off in long shifts (up to 12 hours) was often short (as low
as 3 minutes, with an average of 37 minutes).
Bus and coach drivers often drive for long distances on monotonous roads, work long shifts, all of which are high-risk factors as far as fatigue-related accidents are concerned. Although the hours of work associated with this activity take account of periods when the driver is not driving, it may not always be possible for the driver to ‘rest’ properly during these driving breaks
and this casts doubt over the drivers’ hours regime. However, no studies focusing on bus and coach drivers were identified.
Drivers (other than professional drivers), who drive (usually) smaller vehicles, such as minibuses or people carriers, do not fall within the regulations even though they may be carrying passengers who are dependent upon their ability to drive safely over extended distances and periods of time. Examples of such drivers include teachers, youth workers’ people working in the youth uniformed organisations, churches and community centres. No regulations cover this type of driving, nor are there yet guidelines from Government on this issue.
Managing Occupational Road Risk
It is clear that many types of vocational drivers have driving patterns that are associated with sleep related accidents. Therefore, employers have a major role to play in reducing the risk of their employees falling asleep at the wheel while driving for work. The adoption and implementation of the principles of the Management of Occupational Road Risk42 provide many opportunities for employers to reduce this risk, principally by ensuring that they assess which drivers and journeys are at risk and set schedules that do not require drivers to exceed driver hours, and speed limits.
Principally, employers should:
- Manage the safety of their employees who drive
- Consider and implement the most suitable system of risk assessment and re-assessment for the road safety needs of the company and its employees
- Choose the right vehicle and the safest specification for the needs of the job
- Ensure that work practices, journey schedules, appointments and routes enable drivers to stay within the law
- Provide sensible guidelines about driving and for the use of the vehicles for all employees who may drive for the company.