On-ramp junction is choke point of expressway,and it has import and realistic significance for building and managing expressway to study its capacity.

The traffic momentum differential equation and Euler s equation for the ramp junction is founded by means of differential calculus in this paper,the traffic momentum differential coupled equation is solved by characteristic curve method,two groups of characteristic curves and corresponding related equation in high speed(low density)states and low speed(high density)states are presented.

Based on the analysis of traffic characteristic in the front area of the urban expressway off-ramp grounding joint and according to the typical ramp grounding location, this paper has set up the model for the relationship of capacity and weaving length in weaving section.

Traffic entropy characteristics at on-ramp junctions on urban freeway;

It had been approved that the headways for vehicles following the Weibull distribution function at on-ramp junctions in urban freeway system.

This paper analyzes movement characteristics of the traffic flow on the elevated road,sets up a queuing system model to describe the traffic flow states on the in ramp terminal,and advances a simulation method to obtain its conditional parameters.