The key role of traffic signals

Managing the use of road space is critical for addressing the challenges of reducing congestion, providing rapid and reliable public transport, improving air quality and delivering net zero carbon.

A key tool for achieving this is the effective operation and management of traffic signals.

Traffic signals have the ability to:

  • prioritise public transport, cycles, pedestrians and emergency vehicles over other road users.
  • optimise and balance the inevitable delays on the road network.

Many traffic signal installations have the ability to adjust timings in response to fluctuations in traffic flow but the ability to adapt to reduce delays is limited by the capacity of the surrounding road network and the sophistication of the data available at individual sites.  As further measures are introduced to discourage car use, new techniques which are now available need to be employed to make traffic signals much more intelligent and data-driven, which would allow them to adapt more effectively to changing conditions for all modes in real-time with the potential for less human intervention (e.g. the forthcoming signals pilot in Cambridge involving the application of machine learning and new multi-modal sensors for detection).

The efficient operation of the road network, of which traffic signals are a key component, requires a robust data platform which enables real-time intelligent adjustment of signals and ongoing analysis to allow for operational plans to be iterated and updated in response to changing conditions.  This will help deliver the signals’ operational objective of optimising the movement of people rather than simply reducing vehicle queues.

Such a real-time data platform provides an opportunity for Cambridgeshire to take a more strategic and holistic view of the next generation of network management, by:

  • Monitoring the network in a much more sophisticated and automated way to enable appropriate action to be taken or to trigger (potentially automatically) pre-planned responses.
  • Using data more proactively to update and adjust network operational plans.
  • Communicating more clearly and promptly with travellers either via social media, apps or in vehicle navigation about the problem and the response.
  • Using machine learning to make more informed decisions about signal operations.
  • Supporting the implementation of new road space management measures such as Lane Rental schemes or an expansion of civil parking enforcement.
  • Providing more extensive and reliable evidence about journey times, journey time reliability and more rapid interventions to encourage people onto sustainable modes.

The next generation of network management needs to ensure closer coordination of traffic signal operations with other network management tools to ensure a truly seamless operation. As such, careful consideration needs to be given to how the two traffic signal team functions (operation and maintenance) are structured to deliver the required network management focus on signal operations.

Network management projects

The Smart team are currently working on the following projects:

  • A review of the integrated Highways Management Centre.
  • Vivacity Smart Signals trial.
  • Starling Intelligent Crossing trial.
  • Bus Pinch points.