Summary
The following information is from the Highway Impact Assessment. The Capacity of Junctions JUNCTION 4 – A48/FIVE MILE LANE/ROAD TO PENDOYLAN JUNCTION Junction 4 is a staggered 4 arm traffic signal controlled junction with controlled pedestrian crossing facilities on each approach. The pedestrian crossings are controlled by an all red to traffic stage. It is unknown how often the pedestrian crossing facilities at the junction are called during the AM and PM Peak Periods, therefore, analysis of the junction has been undertaken with and without the pedestrian crossings appearing, providing a best and worst case scenario. No existing queue information has been provided in order to validate the existing predicted modelled queues against. Saturation flows have been calculated based on geometry and the results optimised for delay. The junction has been analysed using JCT Consultancy’s software programme LINSIG version 2 and the results summarised in the following tables below; In 2012 AM and PM Peak Periods the junction operates within capacity with only traffic stages appearing but over capacity if the pedestrian stage appears every cycle. In 2026 AM and PM Peak Periods the junction is predicted to be over capacity with or without the pedestrian stage appearing every cycle. JUNCTION 5 – A4232/COWBRIDGE ROAD/W/A4050/A48 ROUNDABOUT Junction 5 is a traffic signal controlled roundabout. No existing queue information has been provided in order to validate the existing predicted modelled queues against. Saturation flows have been calculated based on geometry and the results optimised for delay. The junction has been analysed using TRL’s software programme TRANSYT version 12 and the results summarised in the following table below; Cardiff City Council have stated the existing roundabout operates under a 128 seconds cycle time. The roundabout nodes are double cycled and the exit pedestrian crossings are single cycled. The analysis has used the same cycle times and double and single cycling. In 2012 and 2026 AM and PM Peak Periods the junction is over capacity. |
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