ANALYSIS OF CAPACITY AND LEVEL OF SERVICE AT UNCONTROLLED INTERSECTIONS UNDER HETEROGENEOUS TRAFFIC CONDITIONS

Unsignalized intersections are defined as the intersections where traffic operates on the basis of the priority of traffic movements. Capacity at unsignalized intersections is defined as a result of the basic capacity within ideal traffic conditions related to various adjustment and correction factors, which included the impact of road environment, geometric design, and traffic conditions. The left-turning movement (in contrast with the straight on or right-turn movements) from the minor street has, for example, the lowest priority according to the corresponding traffic laws in many countries. In Indian condition it is applied to the right turning movements. The performance of an unsignalized intersection is strongly influenced by the delay caused by low-priority movements on minor roads. They are the major source for vehicular conflict resulting delay, accident and congestion. By improving design and operation of the unsignalized intersection we can minimize the user cost delay. Improvement in design and operation largely depends on how accurately capacity and delay are estimated in response to alternative policies and design.At Two Way Stopped Controlled (TWSC) intersections, the minor road is controlled by stop sign and the approaches that are not controlled by any signs referred as major street approaches. A three-legged intersection is considered to be a standard type of TWSC intersection if the single minor street approach (i.e. the stem of the T configuration) is controlled by a stop sign