|M.Sc Student||Danziger Yoav|
|Subject||Analysis of Various Methods for Calculating the Clearance|
Interval in Signalized Intersections
|Department||Department of Civil and Environmental Engineering||Supervisor||Professor David Mahalel|
In recent years, along with the increase in motorization rate, there has been an increase in the congestion level at roads and intersections as well. This high traffic volume is commonly controlled by traffic signals. The separation between various movements is made by the clearance interval. In this work we give an analytical analysis of drivers' behavior at the intersection approach, and examine the consequences of late entering into the intersection. We further make field studies and contrast them with our analytical analysis.
The analytical analysis shows problems of insufficient clearance time in several situations of entering at the end of the yellow light . The field study verified the fact that drivers do not indeed act with compliance with regulations’ guidelines and do not clear the intersection on time especially in congestion. We use the results of the field study to analyze the stopping probability function using the Probit model. A further result of our study shows that the same stopping probability function can be used for calculating the clearance time for both free flow and congestion conditions. Based upon our results, we recommend using the 80-90 percentage of the stopping probability function to calculate the clearance interval.
A further result of the field study shows that more than 50% of the drivers started their movement during the red-yellow light, which is not part of the clearance interval. Therefore it is necessary to shorten the red-yellow or cancel it.