Highways England uses two algorithms to manage traffic on its network: queue protection (QP) to improve safety and congestion management (CM) to improve capacity. It is investing in large programmes to substantially improve network conditions on the strategic road network; this study aimed to consider whether the functionality of the SM algorithms can be delivered in a more efficient or effective way, to increase the benefits of these programmes. The key objective is to improve the experience of road users, by reducing congestion and providing more effective signals and information. Other potential benefits include cost savings, improved safety and reduced emissions. The study considered the use of alternative data sources, modifications to the existing algorithms and entirely new algorithms which could bring improvements to network safety and capacity and reduce operating costs. It found strong potential to improve performance and a strong case for further investment.
The review suggests a high potential for FVD to be used as a data source for QP and CM algorithms,
with far fewer roadside traffic detectors required and significant associated cost savings. It also
identified algorithm options worthy of further investigation, with the potential to significantly improve
the experience of road users on the strategic road network. There is a very strong strategic and
economic case for further investment to gain a more complete understanding through further analysis.
CAVs will not have a significant impact on the business case within a 15-year horizon.
The key recommendations are:
• Perform further investigation into the use of FVD, including performance requirements,
current capability, gap analysis, procurement options, refined business case.
• Review and document performance requirements for QP and CM algorithms, to feed into
decisions about future algorithms.
• Perform more detailed investigation of potential new CM algorithms and decide whether to
proceed with low speed limits if the delay reduction benefits are confirmed as likely to be
high.
• Consider other options not directly in the scope of this project, including improved hard
shoulder monitoring algorithm and holistic CM using speed limits, RM, M2M.