UCL Engineering Exchange


Saving lives with smarter signals

Saving lives with new technologies to develop smarter pedestrian crossings

An image of a crosswalk in London, empty of people

8 January 2019

The problem

The speed and volume of motor traffic on urban roads can act as a barrier to those travelling on foot, sometimes resulting in pedestrian death and injury and contributing to low levels of physical activity and mobility amongst ageing urban populations.

The main tool used to mitigate this severance in London is the signalised pedestrian crossing. However, these crossings often operate in a manner that does not recognise the expectations and needs of the people using them, leading to a high incidence of crossing against the signal, increasing danger and stress. The development of 'smart' urban traffic control systems that actively respond to sensor input provides the technical opportunity for pedestrian behaviour to be taken into account.

Our solution

In 2016, Mike Grahn of London Living Streets, a charity campaigning for pedestrian-friendly streets, won seed funding during an EngEx community research forum on Healthy Ageing and Wellbeing. With support from Dr Tom Cohen of Transport@UCL, London Living Streets launched a project to better understand how pedestrians actually use crossing signals and to test the hypothesis that the current design does not take user behaviour into account.


Since then, Living Streets has developed links with Transport for London (TfL) to collaborate on a substantive piece of work following the scope originally conceived during the EngEx forum.

TfL is undertaking a comprehensive review of their 6,000+ signal-controlled pedestrian crossings with the aim to optimise the control algorithms to reduce wait times for active travel users. Living Streets are measuring pedestrian experience and behaviour at selected sites before and after the signal timings have been adjusted. The results will be used to monitor and improve the operation of signalised crossings by TfL and will be made available for use by other transport authorities.