Transcript Gap acceptance and risk-taking by young and mature drivers

Gap acceptance and risk-taking by
young and mature drivers,
both sober and alcohol-intoxicated,
in a simulated driving task
Professor: Liu
Student: Ruby
Motive
• Speeding and alcohol still remain the two
most factors to fatal road accidents.
• In 1998, young drivers (17-20) comprised
5.4% license population in New South
Wales but almost 15.5% of all fatal
overtaking crashes for that year.
Purpose
Survey the effects of alcohol on a
driver’s perception of speed, hazards
and risk acceptance.
References
1.1 Hazard detection
a. The novice drivers detected hazards lees
quickly and less efficiently. (Deery and Love,
1996)
b. The novice drivers look at the road and lane
markings close to the hood of their vehicle,
but the experienced drivers looked to the
horizon and monitored their side position via
their peripheral vision. (Mourant and
Rockwell, 1970)
References
1.1 Hazard detection
c. Young drivers have faster reaction
times than mature drivers in non-driving
settings. (Summala, 1987)
d. Alcohol-affected drivers, especially in
young drivers, would be expected to
detect approaching vehicles most slowly
and this is more prominent in novice drivers.
(Deery and love, 1996a, b; Deery, 1999)
References
1.2 Time estimations
a. Time to collision show an
underestimate of time. (Schiff and
Dewiler1979)
b. Older drivers (65-83) demonstrated
a tendency to underestimate time to
contact than younger drivers (2045). (Cavallo and Laurent, 1988)
References
1.2 Time estimations
c. The judgments about time to collision
were less accurate for older drivers
(40-64) compared with younger drivers
(18-29). (DeLucia et al., 2003)
d. Young drivers have a higher rate of
accidents involving alcohol. (Triggs and
Smith, 1996)
Method
2.1 Participants
Young volunteers(16): 8 M and 8 F.
age:18-21
Mature volunteers(16):10 M and 6 F
age:25-35
Method
2.2 Alcohol--Alcohol condition (target BAC =0.08g/100ml)
Placebo condition (target BAC =0.00g/100ml)
• Beverage: Vodka mixed orange juice.
• 20min to finish the beverage.
• Before 24h can’t drink alcohol.
Method
2.3 Driving simulator:
a. STISIM Drive (Version 1.1.2.10)
b. Visual images were projected onto
three screens in 135 degrees field
of view.
Method
2.4 Experimental tasks
a. Driving simulator in 15 min
b. After drinking, wait 40 min than task
the following tasks.
Method
2.4.1 detection time
• Press the horn button as soon as they detected
an approaching vehicle on the horizon.
a. The vehicles were showed on opposing lane by
appearing 500m away from behind buildings or
800m away in an area in trees.
b. The approaching vehicle speeds were
randomized between 50 and 90kph.
c. The participant’s speed was limited to keep at
90kph.
d. A straight, left curve and a right curve road.
Method
2.4.2
• When the vehicles would have passed each
other, press the horn button.
a. Approaching vehicles were appeared in
view for 9s then to disappear when they
were 3s away from the participant’s
vehicles.
b. The approaching vehicle speeds were
randomized between 50 and 90kph.
c. The participant’s speed was limited to keep
at 90kph.
Method
2.4.3 Overtaking maneuver
• Requiring to overtake a vehicle being followed.
a. The vehicle being followed was kept 80kph.
b. The successions of approaching vehicles all at
the same speed (50kph-9~17s or 90kph-7~15s)
c. The participant’s speed was limited to keep at
100kph.
Results
3.1 Blood alcohol concentration
a. There was no significant difference
between the mean peak BACs of young
and mature participants.
b. There was a significant between both of
the mean peak BACs and the target BAC
of 0.08g/100ml(t(df=15) =−6.127, p <
0.05and t(df=15) =−6.536, p < 0.05).
Results
3.2 Detection time
a. A significant main effect of roadway
curvature was found on response times to
an approaching vehicle (F(1,24) = 302.64,
p < 0.001)
Results
b. Age was
significant in a
driver’s ability as
an interaction
with straight and
curved sections
of road (F(1,24)
= 8.92, p < 0.01).
Results
c. Alcohol also
significantly
(F(1,31) = 4.94,p <
0.05) interacted
with detection
times.
Results
d. A similar significant
interaction(F(1,24) =
42.38, p < 0.001)
whereby all
participants were
slower in detecting
the presence of
approaching vehicles
on curved roadways.
Results
3.3 Time to collision
Time to collision was always underestimated.
a. A significant
effect (F(1,24) =
44.97,p < 0.001)
was observed
with approaching
vehicle speed.
Results
b. Male drivers
underestimated
TTC to a
significantly
(F(1,28) = 4.36, p <
0.05) lesser
extent than
female drivers.
Results
3.4 Overtaking task
a. A significant age
interaction (F(1,20)
= 13.15, p < 0.005)
with the speed of
approaching
vehicles.
Results
b. Female drivers
created significantly
(F(1,20) = 6.66, p <
0.05) larger headway
distances (16.48m
versus 12.00 m)
between their vehicle
and the vehicle being
overtaken than the
male drivers.
Results
c. A significant
overall effect of
age was found
with mean speed
(F(1,28) = 6.24,p <
0.05).
Discussion
4.1 Detection time
a. On straight roads, mature drivers recorded
marginally faster vehicle detection, it can be
attributed to the variable visual strategies
adopted by drivers of different ages and
experiences.
b. Mature drivers were slower (0.73 s) than young
drivers to detect the presence of an
approaching vehicle on curved sections of road,
perhaps an age-associated increase in reaction
time.
Discussion
4.1 Detection time
c. The attention demands are greater on
curves and the ability to divide attention
is decreased after the consumption of
alcohol.
d. when a vehicle approaches at a fast speed
on a curve, there is increased contrast in
the driver’s retinal image.
Discussion
4.2 Time to collision
a. In considering an approaching vehicle
traveling at a faster speed, the rate of
change of background environmental and
the angular velocity of the approaching
vehicle are both increased. This allows the
viewer a more accurate perception of the
approaching vehicle’s speed, resulting in
more accurate (less underestimated) times.
Discussion
4.2 Time to collision
b. Females tended to make more
conservative estimates of TTC than
males. Males, compared with females,
have an sensitive sense of their own
driving ability and perceive less risk in a
variety of dangerous driving behaviors.
Discussion
4.3 Overtaking task
a. Mature drivers were less anxious when
overtaking in the faster vehicles, perhaps
because these vehicles appeared further
away.
b. Mature participants made overtaking
decisions based largely on the relative
distance of the approaching vehicle,
rather than on relative speed and time.
Discussion
4.3 Overtaking task
c.Females spent more time in the
opposing lane than males.
d. Males have an overconfidence in
driving ability all contribute to the
relatively riskier behavior.
Discussion
4.3 Overtaking task
e. When overtaking in the opposing lane, mature
participants adopted faster speeds than young
participants, because the experienced drivers
showed more caution by making it a priority to
return to their own lane as quickly as possible.
f. Younger and less experienced drivers tend to
overestimate their driving skills and
underestimate potential traffic hazards on the
road.