Traffic operations at short entrance lanes on Dutch freeways

In older freeways built before 1965, the emergency lane was not continued at bridges and other structures e.g. tunnels, viaducts etc. Some on-ramps had a small curve radius, with acceleration lengths shorter than 200 m. These merging lanes are defined as "short entrance lanes". The merging speeds are low and these entrances can become bottlenecks during peak hours. The extent of disturbance at the short entrance Bunnik has been investigated during the evening peak. After analysis of the data it was necessary to define various merging types. For each merging type a gap acceptance function has been produced. Also has been tried to explain the deviation of lane distribution in the vicinity of a short entrance. The freeway simulation model FOSIM is also calibrated for short entrances with the analised data of Bunnik. With different freeway volumes and ramp volumes a first attempt is made to produce a graph, which indicates the uncongested area, the transitional area and the congested area. In the future if this model is validated, it will be possible to evaluate the influence of a short entrance on the traffic flow of a freeway. This model also will be applicable for the design of new entrances.