Summary of IOT Publications
| Title | The Study on the Flow Characteristics in the Off-ramp Area of Urban Expressway and Freeway |
|---|---|
| Dept | IOT |
| Year | 1999 |
| Summary | The purpose of this project is to collect data of flow characteristics in off-ramp area of highway and signalized intersections of off-ramp. This project is divided into two phases. The first phase is to identify the critical point in off-ramp area, and to evaluate whether the Autoscope system is adaptable or not. The main work of the second phase is to collect data within those areas identified from the former phase, and to analyze some variables of flow, like speed(V), flow rate(Q), occupancy(Occ%), etc., in order to find the basic relationships among them. At the same time, it is also expected that the surveyed volume can be used in the building of a vehicle distribution model for each main lane in off-ramp area by an appropriate methodology. It is concluded from the research of this project that the critical point in off-ramp area occurs in the end of the exit lane. For two reasons, the Autoscope system is not suitable for the data collection work in this project: First, the behavior of vehicles are out of control within the peak hours in off-ramp areas. Second, the reliability of this system hasn't been proven. As a result, analysis of data in this project is all done by man-power. The operation of traffic flow of main lanes is definitely influenced by the diverge flow of exit lane from this study. In addition, the vehicle distribution model built by stepwise regression in this project has a good result of calibration, except the outer lanes. However, the result is much better when the two outer lanes are combined into one when running this model. |
| Post date | 1999-04-04 |