Interactions between closely spaced signalized intersections

For long years traffic engineers, try to find a way to model traffic flow characteristics. One of the methods used fort his purpose is evaluating the obtained data by using statistical methods. However, the most important problem is to find a distribution that defines the data properly and also can be applied easily. Because it meets these properties Cowan M3 distribution is widely used in modeling traffic flows. In this study, the distribution which is developed by Cowan (1975) to define the headways between progressing vehicles is tried to explain and its validity is investigated by using data which are obtained from three signalized intersections. Furthermore, it is shown that signalized intersections are significantly effect traffic operations on highways and thus effects the closely spaced unsignalized intersections capacity.