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Fatigue and Driving

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Fatigue and Driving Laurence Hartley, Murdoch University Western Australia. Terminology Europe Sleepy drivers America Drowsy drivers Australia Fatigued drivers All ... – PowerPoint PPT presentation

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Title: Fatigue and Driving


1
Fatigue and Driving
  • Laurence Hartley,
  • Murdoch University
  • Western Australia.

2
Terminology
  • Europe Sleepy drivers
  • America Drowsy drivers
  • Australia Fatigued drivers
  • All synonymous with loss of alertness at the
    wheel, microsleeps, poor vehicle control, single
    vehicle crashes

3
Renewed interest in fatigue
  • Increased economic activity
  • Globalisation
  • Longer journeys
  • Just in time delivery
  • Increased fuel costs mean more work
  • Increased industry competition

4
Size of the problem
  • Fatigue survey crash statistics

5
Surveys
  • U.S. NSF 1998
  • 32 sleep lt 6 h
  • 66 adults with sleep problem
  • 8 with a sleep disorder
  • 38 with excessive day sleepiness
  • 57 have driven drowsy
  • 23 had fallen asleep at the wheel
  • U.K. Maycock 1997
  • 29 close to falling asleep at wheel

6
Fatigue related crashes
  • U.S. AAA 1985, 40 of 221 truck crashes
  • AUS Haworth 1988, 20-30 casualties 25-35 of
    fatal truck crashes
  • U.S. Federal Motor Carrier Safety Administration
    estimates 15 fatals
  • AUS Ryan 1995 estimates 16 trucks
  • U.K. Horne 1995 estimates 16-20 of all

7
AUS fatigue crashes analysed using proxy measures
  • Fatigue state of driver usually unknown
  • A crash is due to fatigue if
  • Driver or Police record it is fatigue
  • AND - PROXY MEASURES
  • Wrong side of road not overtaking
  • Run off road no avoidance manoeuvre, single
    vehicle
  • Alcohol speed not involved

8
All proxy fatigue crashes in AUS
9
Alcohol speed fatalities for 1996 AUS
10
Truck proxy fatigue crashes in AUS
11
All proxy fatigue fatalities injuries by age of
driver AUS
12
All proxy fatigue fatalities injuries by driver
sex AUS
13
AUS drivers reports of falling asleep at the
wheel
  • Males 20 , females 6
  • lt 25y 7 , 25-59y 13 , gt60y 7
  • Metro 9 , country 17
  • White collar 9 , blue collar 17

14
Drivers affected by fatigue
  • People working shift work or long hours
  • With medical problems causing fatigue
  • Commercial and long haul drivers
  • Country drivers, holiday drivers
  • Young male drivers

15
Effect of Sleep Deprivation on Brain Glucose
Metabolism, Belenky,1998
16
Causes of driver fatigue 1
  • Sleep loss

17
Sleep loss
  • U.S. NTSB examined 107 single HGV crashes where
    driver survived records were available for 4
    days -
  • In 58 of crashes driver said fatigued
  • In 18 of crashes driver was asleep

18
Sleep loss
  • In fatigue crashes drivers had
  • inverted sleep/driving cycle
  • driven at night with a sleep debt
  • 5.5 h sleep versus 8.8h in non fatigue
  • fragmented sleep, as in shared driving

19
Sleep lossNodding off whilst driving and hours
slept in AUS
20
Sleep lossNear misses and hours slept before
this trip in AUS
21
Sleep lossHours of sleep and dangerous events
when driving in AUS
  • Drivers with less than 6 h sleep have 3 times
    more dangerous events
  • Drivers with less than 6 h sleep nod off 2.5
    times more often
  • Drivers with less than 6 h sleep use twice as
    much alcohol or drugs
  • Arnold Hartley 1998

22
Sleep LossStutts, Wilkins Vaughn 1999
  • Survey of 1400 US drivers
  • Night shift workers 6 times risk of a fatigue
    crash
  • Less than 6 h sleep 3 times risk of a fatigue
    crash
  • Less than 5 h sleep 5 times risk of fatigue
    crash

23
Causes of driver fatigue 2
  • Time of day - Driving when you normally sleep

24
Time of Day Hamelin,1987
  • Crash risk is lowest between 0800-1900 with less
    than 11 hours driving work
  • Twice the risk of a crash when driving between
    2000 - 0700
  • Twice the risk of a crash with more than 11 hours
    driving work
  • Four times risk of a crash when driving between
    2000-0700 after 11 hours of driving work

25
Time of Day - truckers nodding off Prokop and
Prokop, 1955
26
Time of day - percent crashes Mackie and Miller,
1978
27
Time of day Relative risk of a single vehicle
crash, Kecklund and Akerstedt 1995
28
Time of day - U.S. F.M.C.S.A
29
Time of day - U.S. F.M.C.S.A
30
Time of day- Hours of sleep Kogi, 1985
31
Causes of driver fatigue 3
  • Hours of work

32
Hours of workMackie Miller 1978
  • Steering lane wandering worse after 8-9 h
  • Performance worse after 4 days driving
  • In 750 fatigue single truck crashes twice
    number of crashes in second half of the trip
  • In fatigue single truck crashes odds of crash
    increased after 5 h

33
Hours of work-relative crash riskFolkard, 1997
34
Hours of work -U.S. F.M.C.S.A.
35
Hours of work -U.S. F.M.C.S.A.
36
Hours of Work Hartley, Arnold et al. 1995
  • 50 of truck drivers exceed 14 hours of work in
    any 24 hours
  • 10 of truck drivers exceed 18 hours work in any
    24 hours
  • 12 of drivers obtain less than 4 hrs sleep on
    any day

37
Countermeasures to fatigue 1
  • Behavioural countermeasures

38
Behavioural countermeasuresHorne Reyer, 1996
  • USELESS
  • Window down radio up
  • exercise
  • USEFUL
  • 2-3 cups of coffee before a
  • 15 min nap (longer naps need time to recover)

39
Countermeasures to fatigue 2
  • Technological countermeasures

40
Technological countermeasuresHardware to measure
fatigue
  • Perclos - in-vehicle video of 80 eyelid closure
  • correlations of 0.8 with lapses on Dinges
    Vigilance Task better than self reported
    drowsiness or anything else
  • in-vehicle device now available
  • But, it can only warn the driver
  • What can the driver do on the road?
  • Will drivers ignore it?
  • Will drivers supervisors rely on it?

41
Technological CountermeasuresHardware - SAVE
Brookhuis et al. 1998
42
Technological countermeasuresSoftware to predict
fatigue
  • Score based on prior sleep, wakefulness time of
    day-Akerstedt Folkard, 1997
  • Score base on hours of work time of day -
    Fletcher Dawson, 1998
  • US Army Sleep Management System - activity meter
    records sleep integrates with time of day to
    predict sleep need performance-Belenky, 1998

43
US DoT Countermeasures Research Program
  • Trip planning, hours of service
  • Sleep, napping, circadian, melatonin
  • Drugs
  • Bright light
  • Fitness for duty measures
  • Vigilance testing
  • Vehicle based measures
  • Math models of sleepiness

44
Countermeasures to fatigue 2
  • Regulations governing work rest

45
RegulationsU.S.A.
  • 10 h driving, 8 h rest, 60 h duty in 7 days - no
    reference to a 24 h clock
  • So driver can start work 6 h earlier each day
  • Driver can be on duty for 16 h in 24 h
  • Enforced by police log books
  • Regulations under review
  • Proposed regulations stand little chance of being
    accepted

46
RegulationsEurope
  • 9-10 h driving daily
  • 56 h driving per week
  • 9-11 h rest, or 12 h in 2 periods
  • 24-45 h continuous rest per week
  • enforcement - police tachographs

47
RegulationsAustralia
  • 14 h work per day
  • 8 h non work
  • 6 h continuous non-work
  • 84 h work per week
  • 1 day off work per week
  • Enforcement-Duty of Care under Occupational
    Safety Health Inspectors

48
RegulationsAustralia
  • employer who contravenes the duty of care by
    exposing employees to a hazard can be fined
    100,000
  • where the hazard causes injury or death a fine of
    200,000 is imposed
  • employee who contravenes duty of care can be
    fined 10,000 or 20,000
  • workplace review by complaint or random
    inspection which leads to an
  • Improvement or Prohibition notice.
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