The construction of Shanghai express overhead road network greatly increases the road network volume of the road network in the urban district,effectively disperses the traffic in the central urban district,improve the transportation efficiency.

The traffic organization of the exist ramp of the elevated expressway with the linking-up section of the ground intersection is the most important to the urban traffic system.

The elevated expressway is different from conventional expressway and urban street in design speed,vehicle composition and service function,so the lane width should be also different from that of other roads.

By analyzing the data for traffic on the viaduct network in 2005 within the Inner Ring Rd, an initial appraisal is made of the operation conditions such as the service level, main route flow, average speed and flow and the crowded spatial distribution.

With the form of the "*" word model road network truss of shaan xi province,the transportation efficiency of shaan xi province highway network must be improved in order to according to the development step of road network.