Lecture 10 - Highway Engineering by Dr.Abdul Sami

8/3/2019 Lecture 10 - Highway Engineering by Dr.Abdul Sami

1/14

1

Perception/Reaction Time


2/14

2

Perception-Reaction Process

Perception

Identification

Emotion

Reaction (volition)

PIEV

Used for Signal Design and Braking Distance


3/14

3

Perception-Reaction Process

Perception Sees or hears situation (sees deer)

Identification Identify situation (realizes deer is in road)

Emotion Decides on course of action (swerve, stop, change

lanes, etc)

Reaction (volition) Acts (time to start events in motion but not

actually do action) Foot begins to hit brake, not actual deceleration


4/14

4

Typical Perception-Reactiontime range is:

0.5

to 7 secondsAffected by a number of factors.

What are they?


5/14

5

Perception-Reaction Time Factors

Environment: Urban vs. Rural

Night vs. Day

Wet vs. Dry

Age

Physical Condition: Fatigue

Drugs/Alcohol

Distractions


6/14

6

Perception-Reaction Time Factors

medical condition

visual acuity

ability to see (lighting conditions, presence of fog,

snow, etc) complexity of situation (more complex =more time)

complexity of necessary response

expected versus unexpected situation (traffic lightturning red vs. dog darting into road)


7/14

7


8/14

8

Perception Reaction Time (PRT)

Time from Perception to Initial Reaction to

Stimulus (Example)


9/14

9

Age

Older drivers

May perceive

something as ahazard but not act

quickly enough

More difficulty

seeing, hearing,

reacting

Drive slower


10/14

10

Age

Younger drivers May be able to act quickly but not have experience to

recognize things as a hazard or be able to decide what to do

Drive faster

Are unfamiliar with driving experience

Are less apt to drive safely after a few drinks Are easily distracted by conversation and others inside the

vehicle

May be more likely to operate faulty equipment

Poorly developed risk perception

Feel invincible, the "Superman Syndrome

Human Factors - Perception and Reactionby Joseph E. Badger. [email protected]


11/14

11

Alcohol

Affects each person differently

Slows reaction time

Increases risk taking

Dulls judgment

Slows decision-making

Presents peripheral vision difficulties

Human Factors - Perception and Reactionby Joseph E. Badger. [email protected]


12/14

12From: Driver Characteristics and Impairment at Various BACsH. Moskowitz, M. Burns, D. Fiorentino, A. Smiley, P. Zador


13/14

13

Experience

Even NASCAR drivers practice

Familiarity

Faster on familiar

Unfamiliar more distracted

Rental car on unfamiliar road at 10 pm when it starts

to rain (What is the driver doing?)


14/14

14

Weather

Fog

Rain

Ice

Snow

affects ability to see (snow, fog)

changes ability to stop (ice, snow, wet)

Lecture 10 - Highway Engineering by Dr.Abdul Sami

Documents

Transcript of Lecture 10 - Highway Engineering by Dr.Abdul Sami