Module 1 : Traffic Stream Characteristics

Lecture 01 : Fundamental Parameters of Traffic Flow

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	Speed Speed is considered as a quality measurement of travel as the drivers and passengers will be concerned more about the speed of the journey than the design aspects of the traffic. It is defined as the rate of motion in distance per unit of time. Mathematically speed or velocity $v$ is given by, $$v = \frac{d}{t}$$ (1) where, $v$ is the speed of the vehicle in m/s, $d$ is distance traveled in m in time $t$ seconds. Speed of different vehicles will vary with respect to time and space. To represent these variation, several types of speed can be defined. Important among them are spot speed, running speed, journey speed, time mean speed and space mean speed. These are discussed below.