1

Lee Di Milia; PhD

Drive-in drive-out workforce:Extent and implications.

2

Overview:

• On-shift safety is critical but . . .

• Safety is more than on-shift

• Funding to examine driving and

SW: Why?

• Number of risk factors

– Shiftwork + Time-of-day + Task

– Growth in 12h & relocation

effect

3

Risk Factors:

1. Shiftwork

• Human biology is diurnal & hard-

wired; Eg: body temp; cortisol;

melatonin; mood & performance

• SW disrupts synchrony & pacemaker

is inflexible conflicting messages

sleep drive but cortisol & body

temp

4

Health impacts of SW:

• Physiological; Psychological; Social

• Sleep after NS 2-4h less than day

• Mood; Impaired performance

RT; attention lapses

– Self paced work (Smith, 1994)

• Fatigue & sleepiness

5

2: Time of day:

6

3: Driving task:

• Monotonous

• ‘Boring’ environment

• Unforgiving roads

• Summary: Sleep loss + TOD +

Task

• Driving – sensitive to sleep loss

& bio demands

7

Evidence to date:

• Long hours & driving do not mix

– Medical students; manufacturing

– SW + 12h risk of fall asleep

compared to DW

– < 6h sleep: driving impairment

attention lapses, lane drift

• No studies of LDD & SW

8

Study:

• Surveyed 1600 drivers;

Capricorn & Peak Downs H’way

• Between 08 – 10

• Some 21% of traffic flow

• Work, travel and fatigue

9

Results:

• Two excluded for BAC ≥ 0.05

• 12% SW; Miners = 93%

• 30% 4x12h NS; 29% 2x12 NS

(Range = 1–14)

• One-way travel 211 km (max 655

km)

• 19 drivers between shifts – 581km

• One driver; left at 02:00 to drive

1300

10

Results:

0

1

2

3

4

5

6

7

8

9

NSW SW

Sleepiness

• ≥ 7; SW = 19%; NSW = 1%

11

Results:

• 13% fell asleep driving to DS

• 23% fell asleep driving from NS

• Fall asleep linked with lane

drifting

• Linked to <6h sleep

• Return travel – bi modal

12

Discussion:• Long distances driven post NS

• Some indicators of increased accident risk but none reported!!

• Simulator studies show ≥7 with increased accidents

• Seems that shift schedule drives travel pattern

• Expect DIDOW estimate to be higher?

13

Solutions:

• Education

• Sleep facility

• Modify schedule design

• Transport arrangements