WINNER : Best Overall Paper 2022
Following the release of TSM Chapter 6, the minimum green to a full green traffic phase can be reduced to 5 seconds at sites with very low flows. TfL has undertaken on-street trials to assess the impact and benefit of reducing this minimum to 5 seconds with a focus on safety, user behaviour and performance at 12 signalised junctions. Both pedal cycle only and mixed road traffic phases were selected for the trial, phases which were typically signalised exits from private dwellings, businesses or parks and appeared in their own demand-dependant stage.
Before and after surveys using camera footage have provided evidence of the impacts of reducing the minimum green time and to provide proof of concept. This evidence has permitted a wider range of sites to be selected and design guidance produced, which outlines criteria for site selection.
The benefits of lowering the minimum full green to a traffic phase has been measured in relation to the ability for the junction to re-balance the additional green time to busy approaches, specifically those with bus routes on to improve their performance. Additionally, reducing the minimum green provides an opportunity for a lower cycle time at some sites which can assist with pedestrian wait time.