The main focus of this study was to determine the effectiveness of the Auckland ramp signalling system and to estimate the benefits/costs. In brief, the analyses comprised comparing vehicle speeds and flows obtained from the inductance loop occupancies, before and after implementation at the last on-ramp prior to entering the Harbour Bridge in central Auckland. As expected, the study results clearly showed that the mainline weighted average speed (WAS) and total throughput (TT) on the motorway increased. Based on the analyses undertaken during the full 4-hour congested afternoon peak period, the vehicle flows increased from 66 to 85 vehicles per hour per lane. Similarly, the vehicle speeds were 10 to 20 km/h higher. The merging lane, L1, obtained the largest percentage benefit in throughput, up about 7 per cent compared to 3 to 4 per cent for the other three mainline lanes. However, the throughput of these non-merging lanes, L2 to L4, was generally significantly higher than the merge lane, L1. In particular, L4, the fast lane was averaging nearly 2250 vehicles per hour. The results also showed that vehicles flow breakdown or congestion occurred at about 20 per cent loop occupancy. (a) For the covering entry of this conference, please see ITRD abstract no. E217099.
Abstract