Prof Jim Horne

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• Prof Jim Horne
• Director, Sleep Research Laboratory
• Loughborough University

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Sleep-Related Road Crashes

• Professor Jim Horne
• Dr Louise Reyner
• Sleep Research Centre, Loughborough University
• sleep.lboro.ac.uk

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Impact of Our Research
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Prevalence of SRCs

• About 10 of all road crashes largely due to
  sleepiness
• 20 for major, non-urban roads
• 50 for early morning on dull roads
• Worse because of the higher impact speed
• Kills more drivers and passengers than alcohol

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Selby Rail Crash 0612h car drifts off road,
down embankment onto railway. Hit by passenger
train - derailed, then hit by goods train. 100
fatal serious injuries
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10 times more likely to fall asleep early morning
than later in day
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Characteristics of Sleep Related Crashes

• Exclude
• mechanical faults, weather, bad road, speeding,
  driving too close, alcohol
• Nil braking or swerving
• MAYBE prior lane drifting, variable speed
  unlikely
• CLEAR VIEW of object hit for over 7 sec
  (microsleep) prolonged inattention, not
  momentary distraction
• THEREFORE - driver unconscious why ?
  Illness,drugs, medications ?
• Driver denies sleepiness for various reasons
• Other Factors dull road, early morning/mid
  afternoon,

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Dull Roads only unmask sleepiness dont cause
it
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Highway Hypnosis

• Does not exist no basis in law
• Just another name for sleepiness

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Driving Without Awareness

• Not a sign of falling asleep
• Mind preoccupied by other thoughts
• Same as watching TV or reading without
  awareness

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Drivers insight into their sleepiness before
falling asleep at the wheel
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Unforewarned sleep attacks in drivers

• Healthy drivers involved in sleep-related crashes
  often report these attacks
• Deny i) falling asleep
• ii) sleepiness beforehand
• I dont know what happened I was not tired
• WHY ? - Are they narcoleptic ? No !

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Driver has little knowledge of having fallen
asleep WHY ?

• We cant remember being asleep - unless sleep
  lasts beyond 2 min
• Cant drive for this period of time
• Therefore, if a driver falls asleep wont
  remember doing so.

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Drivers Poor Recollection of Being Sleepy
Beforehand cant remember their sleepiness,
either But, Neither Can You !

• Remember sleepiness last night when it began ?
• More hazy if one thinks back 2-3 nights
• Similarly - poor recollection of hunger and
  thirst
• Forget such useless information
• No excuse for drivers falling asleep at the wheel
• WE DO KNOW WHEN WE ARE SLEEPY
• especially at night when usually asleep

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Drivers Poor Recollection of Prior Sleep
Sleepiness
Falling asleep Unlikely to acknowledge this
unless asleep for over 2 min Prior
Sleepiness Cant remember this either Little
point in pursuing either in subsequent interviews
with driver
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Countermeasures to Driver Sleepiness(Self-Evident
of Sleepiness)

• ACTUAL DRIVER SUGGESTIONS
• Fix hair in sun roof
• Drawing pins under an elastic band around the
  wrist
• Set challenges (e.g. make hot drinks while
  driving)
• Shake head violently from side to side
• Suck lemons
• Drive without shoes
• Drive faster
• Move seat to uncomfortable position

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When drivers experience any effort to stay awake,
and utilise methods to stay awake (cold air to
face, turn up radio etc) Driving ability is
markedly worse
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Some car manufacturers think the solution to
driver sleepiness lies in better car design - not
with the driver
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Misleading Message sleepiness is overcome by
better ventilation
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Mobile Office / Bed on Wheels

• Car and truck interiors well designed
• Too conducive to sleep ?

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Other Effects of Sleepiness

• Visual illusions - fatal attractions
• Increased euphoria/optimism about driving ability
  
• Distorted perception of impaired driving
• Alcohol twice as potent when sleepy

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AGE SEX OF SRC DRIVERS (m 226 f 41) Values
similar to RTCs
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Sleep-Related Crashes Age and Time of Day

• For one reason or another
• Younger adults tend to crash early AM
• Older people tend to crash early PM

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Vulnerable Group 1 Young Adults

• 18-30 y adults need sleep to greater extent
• Have deeper sleep
• More impaired by monotony when sleepy
• Sleep loss can produce euphoria
• Overestimate ability to stay awake
• Peer pressure to drive early am ?
• Sleeping passengers portend a sleepy driver

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Vulnerable Group 2 Truck Drivers (50 SRCs by
drivers at work)(Reyner et al. 2001, UK Dept
Transport, Research Report 22)

• 70 of which trucks (LGVs)
• 15 company cars
• 15 vans
• lt 1 coaches

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Fall-asleep Truck Crashes

• Twice as likely (as car crash) to result in death
• Driver falling asleep is probably the commonest
  cause of a truck crash and most likely cause of a
  truck being written off
• Largest single cause of death at any type of work
  (including building sites)
• Usual crash barriers will not stop 40 tonne truck
  travelling at 55 mph (90 kmh)
• Driver vulnerable to obesity and sleep apnoea

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Truck Drivers Undiagnosed Sleep Apnoea (gagging
V heavy snoring)

• High exposure to driving 70,000 miles/year
• More likely to be at night during the trough
• Many obese probably half of whom have
  undiagnosed sleep apnoea, but sleep well
• Frequent obstructed breathing severely disrupt
  sleep, and excessive daytime sleepiness (EDS)
• There is a need for screening, here, and because
  
• rapid, effective treatment
• undertaken in positive manner

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Vulnerable Group 3 Shift/Nightworkers

• Homeward drive
• Early morning
• After 12h night-shift
• Especially after first night on this shift
• On a dull road
• DANGEROUS COMBINATION DRIVER UNFIT TO DRIVE

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Driver Sleepiness Simulator Studies (all
funded by DfT published reports)

• Driver awareness of sleepiness
• Reaction time
• Countermeasures naps, caffeine (good)
• cold air, radio
  (bad)
• Sleepiness V low blood/breath alcohol
• Obstructive sleep apnoea
• Over the counter medicines

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Driving Simulator

• Real car, immobilised with fully interactive
  controls
• Large projector screen
• Computer generated roadway
• MONITOR
• Lane drift
• Brain waves
• Eyes Face
• Subjective reports

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View through windscreen
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Alcohol Sleepiness

• Alcohol is soporific
• Any alcohol intake is dangerous for an already
  sleepy driver
• Breath/Blood alcohol levels are a poor guide to
  impairment in sleepy drivers
• Men less likely to notice added alcohol effects
  with sleepiness, despite impaired driving

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France All legal BAC levels recorded
Fatigue, alcohol, and serious road crashes in
France Philip et al (2001) BMJ 322 829-830

• fatal crashes 0000h - 0500h
• nil - BAC lt10mg 7
• BAC gt10mg 26
• Sleepiness combined with as little as 10mg
  BAC triples the likelihood of death or serious
  injury at this time of day

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Countermeasures for Sleepy Drivers

• Effect of a break with caffeine and or nap

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30 min Break outcome from our published research

• IF NOT TOO SLEEPY
• FIND SAFE PARKING SPACE
• THEN
• 150 mg caffeine (not
  effective for 20 min)
• Followed by nap of max 15 min
• (resting eyes/dozing is also good)
• (set phone
  alarm)
• Freshen up - 5 min

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The Driver Reviver

• Scientifically tested
• Enables 15 min nap
• Pink noise - relaxing
• Blocks out noise

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THATS IT !THANKS