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.Sheppard and Pattinson

19901986

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 NahomTrigs et al.

19921994

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