Abstract
This report describes a mathematical evaluation method of merging traffic on a center ramp terminal which is often designed for urban expressways. In order to make the evaluation, the merging probability on the center ramp terminal was compared with that of an usual side ramp terminal. Traffic flow on the both ramp terminals was recorded by using TV camera. The traffic volume and speed as well as the gap distribution were measured and the acceptable gap size was determined. Then the merging probability was computed based on the gap distribution and the acceptable gap for both the center ramp and the side ramp making use of probability theory. It is found that the merging probability of the center ramp wass about 10% smaller than that of side ramp terminal. It is suggested that careful attention should be given to the design and the operation of center ramps.
