Explanation of PIEV theory | Importance of PIEV theory | Perception Time | Intellection time | Emotion time | Volition time

PIEV Theory: -

The reaction time of the driver is time taken from object is visible to the driver and the brakes are effectively applied. The value of the reaction time of the driver depends on various factors. 

The reaction time can be split up into two parts:

1. perception time
2. brake reaction time

The perception time is the time driver to realize that the brakes are to be applied. It is the time from object comes on the line of sight of the driver to the he realizes that the vehicle needs to be stopped.

The brake reaction time also depends on several factors including the skill of the driver, the type of the problems, and various other environmental factors.

PIEV Theory Diagram

PIEV theory full form is perception, intellection, emotion and volition. PIEV theory is a fundamental concept in transportation engineering that helps to understand how human factors can impact road safety. PIEV stands for:

(1) Perception Time:
Perception time is the time required for the sensations received by the eyes or ears to be transmitted to the brain through the nervous system and spinal chord.

(2) Intellection Time:
Intellection time is the time required for understanding the situation. It is also the time required for comparing the different thoughts, regrouping and registering new sensations.

(3) Emotion time:
Emotion time is the time elapsed during emotional sensations and disturbance such as fear, anger, or any other emotional feelings such as superstition etc. with reference to the situation. Therefore the emotion time of a driver is likely to vary considerable depending upon the problems involved.

(4) Volition Time:
Volition time is the time taken for the final action. It is also possible that the driver may apply brakes to take any avoiding action by the reflex action, even without thinking.
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PIEV theory is used to calculate the reaction time of a driver for calculating sight distance in highway geometric designs. It is also possible that the driver may apply brakes or take any other avoiding action like turning, by the 'reflex action', the normal thinking process, which is probably the minimum time for taking a preventive action like brake application. The PIEV time of a driver also depends on several factors such as the physical and psychological characteristics of the driver, type of problem involved. environmental conditions and temporary factors (e.g. motive of the trip, travel speed, fatigue, consumption of alcohol, etc.).

The total reaction time of driver in simple situation may vary from 0.5 seconds and for complex situations may vary from 3 to 4 seconds or even more.

Intellection time in highway engineering.

Intellection time is the time required for understanding the situation. It is also the time required for comparing the different thoughts, regrouping and registering new sensations.


PIEV theory and its importance.

PIEV theory full form is perception, intellection, emotion and volition. PIEV theory is a fundamental concept in transportation engineering that helps to understand how human factors can impact road safety. PIEV stands for:
(1) Perception Time:
Perception time is the time required for the sensations received by the eyes or ears to be transmitted to the brain through the nervous system and spinal chord.
(2) Intellection Time:
Intellection time is the time required for understanding the situation. It is also the time required for comparing the different thoughts, regrouping and registering new sensations.
(3) Emotion time:
Emotion time is the time elapsed during emotional sensations and disturbance such as fear, anger, or any other emotional feelings such as superstition etc. with reference to the situation. Therefore, the emotion time of a driver is likely to vary considerable depending upon the problems involved.
(4) Volition Time:
Volition time is the time taken for the final action. It is also possible that the driver may apply brakes to take any avoiding action by the reflex action, even without thinking.

Importance:

PIEV theory is used to calculate the reaction time of a driver for calculating sight distance in highway geometric designs.