Transcript Differences in traffic judgments between young and old

Differences in traffic judgments between
young and old adult pedestrians
Professor: Liu
Student: Ruby
Motive & Purpose
• Motive
– Older pedestrians’ crashes has a high
percentage than young pedestrians’.
• Purpose
– The authors want to know the behavior between
younger and older pedestrians.
Reference
Authors
Year
Result
Alexander et al.
1990
Sheppard and Pattinson 1986
Older pedestrians have a higher risk
when they crossing the road than
younger pedestrians.
Fildes et al.
1994
Pedestrians accounted for 19% dead
and almost have 30% are older
people (>65 years old).
Stelmach and Nahom
Trigs et al.
1992
1994
The older people’s perceptual,
sensory and cognitive are reduced.
“Blackspot” Accident Analysis
• ‘Blackspots’
– Road sites which show high crash records.
– 4 crashes within a midblock section of 1 km, or six
pedestrian crashes within 1 km in a local traffic
area within a 3-year period is a ‘blackspot’ area.
Method
• Duration
– 1987-mid-1995
• Total accident
– 52
• Pedestrian
– 19 older pedestrians (65 years old)
– 33 younger pedestrians
Road location
• The older pedestrians are
lacking of consideration
for traffic in the far-side
lane.
• Maybe we can say that
higher crash rates in the
far-side lane because the
older pedestrians walk
slowly.
First test
• Location: shopping centers on arterial roads in
Melbourne.
• Set up two video cameras to observe the
people who across the roads.
• 80 older and 80 younger pedestrians.
• 10 A.M and 1 P.M. on weekdays.
Layout of observational filming
Results- Kerb delay
• Kerb delay
– The duration in the
back of the last car
passed a waiting
pedestrian to the first
step forward onto the
roadway.
• There was a
significant difference
between groups for
kerb delay.
Results- Gap acceptance
• Gap acceptance
– The distance of a near-side oncoming car from a
pedestrian at the first step forward to cross the road.
• The younger pedestrians significant shorter
gaps than older pedestrians.
Results- Time-of-arrival of car and
pedestrian crossing times
• Time-of-arrival of car and pedestrian
crossing times
– The closest near-side car were calculated from
the time when a pedestrian took the first step
forward to cross at the time when the vehicle
reached the crossing point.
Results- Time-of-arrival of car and
pedestrian crossing times
Results- Crossing styles
• Crossing styles
– The crossing times and the traffic distribution
during the road cross fro all pedestrians in each
groups.
• Non-interactive who adopted an ‘extra safe’.
• Interactive crossers who adopted a less safe
strategy.
– Near-side traffic
– Far-side traffic
– Both direction of traffic
Results- Crossing styles
Discussion
• The older pedestrians took longer to leave the kerb
after a car passed their line of crossing.
• Older people behave in a less safe than younger
adults when making judgments on gaps in the
traffic.
• Many older people may have difficulties judging
the nearness of a car when stepping off the kerb.
Discussion
• In a complex environment of two-way
traffic, older people will think two problems,
one is the directions of traffic and another is
making decisions.
• Some older people will cross the far-side
traffic, in this reason they will get crash
very often because their walking speed is
very slowly.
Second test
• Location: shopping centers on arterial roads in
Melbourne.
• Set up two video cameras to observe the
people who across the roads.
• 40 older and 40 younger pedestrians.
• In gap acceptance , time-of-arrival and
crossing time measures were obtained for 33
younger people and 31 older people.
• 10 A.M and 1 P.M. on weekdays.
Results
• Average traffic flow and car speed were
comparable for the two groups.
Results-Kerb delay
• No significant in these two groups.
Result-Gap acceptance
• No significance here.
Probably the experimenter number is too
small.
Result-Time-of-arrival of vehicle
and pedestrian crossing times
Discussion
• The older pedestrians behaved much more
like younger and a little different from those
in the first study.
• The older people in the first study over
compensate than younger people.
General Discussion
• When age increases, the ability to cross the
road becomes more difficult.
• The older people difficulties in judging the
gaps in traffic.
• Older pedestrians are impaired compared to
younger people because they take in less
information and are less able to process the
information to reach a decision.
General Discussion
• The older people hard to change their
attention because their capacity reduce.
• Older people are hard to do the actively
selecting or dividing attention between
sources of information in order to make the
right judgments.
Conclusions
• When older people cross the road, they tend
to adopt when the road have been identified.
• Gap acceptance and time-of-arrival
judgments are factors in safe road crossing
behaviors on the road