One liners - Transportation Engineering for GATE, PSUs - Part 5

Hello there,
How have you been? Here is another round of one liners for your preparation for the GATE and PSUs examinations.

The diagram which shows the approximate path of vehicles and pedestrian involved in accidents is known as collision diagram.
With increase in the speed of the traffic stream, the minimum spacing of vehicles increases.
Traffic volume is equal to traffic density * traffic speed.
Practical capacity is also known as design capacity.
With increase in speed of the traffic stream, the maximum capacity of the lane first increases and then decreases after reaching a maximum value at optimum speed.
Equivalent factor of passenger car unit(PCU) for a passenger car as per IRC is 1.0.
Scientific planning of transportation system and mass transit facilities in cities should be based on origin and destination studies.
The diagram which shows all important physical conditions of an accident location like roadway limits, bridges, trees and all details of roadway conditions is known as condition diagram.
When the speed of traffic flow becomes zero, then traffic density attains a maximum value whereas traffic volume becomes zero.
On a right angled road intersection with two way traffic, the total number of conflict points is 24.
The background of informatory sign board is yellow.
Level crossing is indicated by a warning sign.
“Dead Slow” is a regulatory sign.
The most efficient traffic signal system is flexible progressive system.
The provision of traffic signals at inter-sections reduces right angled collisions but may increase rear end collisions.
Stop or red time of a signal is the sum of go and clearance for the cross flow.
Clearance time is generally 3 to 5 seconds.
The cycle length is normally 40 to 60 seconds for two phase signals.
Centre line markings are used in roadways meant for two way traffic.
The particular places where pedestrians are to cross the pavement are properly marked by the pavement marking known as crosswalk lines.
The entrance and exit curves of a rotary have different radii and different widths of pavement.
When two equally important roads cross roughly at right angles, the suitable shape of central island is circular.
Beyond 5000 vehicles per hour the rotary may not function efficiently.