TRANSPORTATION TERMS

85th percentile value

is the commonly used statistics to determining upper speed limits of vehicles.

Basic capacity

is the term used to designate the maximum number of passenger cars that can pass a given point per hour under the most nearly ideal roadway and traffic conditions.

Diamond shape

the standard sign shape which is used only to warn of existing or possible hazard.

Emotion time

is the time elapsed during emotional sensation and disturbance such as fear, anger or any other emotional feelings such as superstitions with reference to the situation.

Equilateral triangle shape

the standard sign shape which is reserved exclusively for the yield sign.

Growth factor method

is a method of trip distribution involving the use of existing volumes of interzonal traffic to measure friction prior to the expanding volume between two points in proportion to an inter-actance factor.

Intellection time

is the time required for understanding the situation which is also the time required for comparing the difference thoughts, regrouping, and registering new sensations.

Octagon shape

the standard sign shape which is reserved exclusively for the stop sign.

Perception time

is the time required for a driver to realize that brakes must be applied.

Possible capacity

is the maximum number of vehicles that can pass a given point on a lane or roadway during one hour under prevailing roadway and traffic conditions.

Reaction time

is the time taken from the instant the object is visible to the driver to the instant the brakes are applied effectively.

Rectangle shape

the standard sign shape which is used for regulatory signs with the expectation of stop and yield signs.

Rectangle shape

the standard sign shape which is used for guide and information signs.

Round shape

the standard sign shape which is used for the advance warning of a railroad crossing.

Sight distance

is the distance at which a driver can see an object lying in the roadway ahead. It should equal or exceed the stopping sight distance.

Traffic capacity

In the design of auxiliary lanes, it is known as the number of cars that need to be stored during peak hours.

Traffic density

is the number of vehicles occupying a unit length of the lane of the roadway at a given instant, usually expressed as vehicles per km.

Traffic volume

is the number of vehicles that pass a point on a highway during a specified time interval.

Volition time

is the time taken for the final action.