HAROLD: HAzards, ROad Lighting and Driving

The frequency and severity of road collisions are reduced if drivers are able to detect and recognize potential hazards in sufficient time to take evasive action such as braking and steering. An improvement in detection time measurable in hundreds of milliseconds could substantially increase the probability that a crash can be avoided.

After dark, visual functions such as reaction time are significantly reduced, and road lighting is installed as a countermeasure to this visual impairment. Road lighting is of particular importance for revealing hazards beyond the reach of vehicle headlights such as pedestrians emerging from the side. The British Government recognise the need for significant reductions in road traffic collisions, particularly those involving vulnerable road users such as pedestrians, and committed to enhancing protection of these people in the 2015 British Road Safety Statement.

This project will investigate the way in which lighting can be used to enhance safety on main roads. Specifically, we seek lighting that increases the chance of drivers seeing a hazard and reduces the time taken to see the hazard. These hazards include other vehicles, stationary objects and pedestrians.

There are two problems with the current situation. First, while British and European standards provide guidance on road lighting, the empirical basis of the recommended lighting is not clear. Therefore, we do not know whether they recommend optimal conditions. Second, we suspect there is a better way for enhancing the detection of pedestrians when they are otherwise unexpected, which is frequently the case for pedestrians on main roads. This is that pedestrians should use a pulsing or flashing LED band, worn on the wrist or ankle to take advantage of bio-motion. An LED band could provide a low-cost counter-measure to reduce the risk of accident.

To investigate these proposals we will first carry out experiments to find out how the detection of hazards including pedestrians is affected by changes in lighting, using variations in the intensity and spectrum (colour) of lighting. Whilst drivers should be continuously scanning for potential hazards, there are many distractions - listening to music, speaking to passengers and looking at maps or digital navigation devices. These distractions reduce our ability to detect hazards. We will therefore also investigate how hazard detection is affected by distraction and whether optimal lighting can mitigate the distraction decrement. This research is of particular benefit to elderly drivers; the elderly tend to have poorer vision and, overall, they perform worse than younger people when driving with distractions

From these data we will identify the changes in lighting conditions likely to improve safety. These recommendations will be validated by manipulating lighting conditions within a high fidelity driving simulator. The simulator places the test participant in a more realistic setting while still maintaining control on road situation and ensuring participant safety. To facilitate implementation of results we will work to ensure the guidance and standards documents used by lighting designers are revised to include the proposed criteria.

The aim of this work is to reduce road traffic collisions after dark by improving drivers' ability to detect potential hazards in time to take avoiding action. While the work considers collision with other vehicles and static objects on the road, particular attention is paid to collisions which involve pedestrians. Road accident data for 2015 show there were over twenty thousand collisions involving a pedestrian. Thirty four percent of these occurred on a major road: these were more likely to involve a pedestrian fatality or serious injury, in part due to greater vehicle speed, and were more likely (relative to minor roads) to occur at night. While higher light levels may help, there is likely to be a ceiling to the effect, beyond which increased lighting will not improve road safety. Lighting engineers must also consider side effects such as sky glow and energy use - road lighting across the 28 EU countries costs public authorities almost 4 billion Euros each year.

By including elderly people within the research we ensure that their needs are met, a key concern since vision deteriorates with age and poor visual conditions is a common reason given by the elderly to avoid driving at night. This research therefore has the potential to improve mobility choices and social inclusion for elderly drivers.

The general public is expected to benefit from the proposed research through a reduction in the number and severity of night-time accidents on main roads. The UK government will also benefit by helping them to meet the commitment to improving safety for vulnerable road users such as pedestrians, as expressed in the 2015 British Road Safety Statement. Doing so will not only save lives, and save distress, but contribute to the national economy by reducing the £10.7 billion annual prevention value of reported injury accidents on UK roads.

Manufacturers of lamps and lanterns used for road lighting will benefit through the establishment of improved lighting design criteria as targets for value engineering. The new guidance will be developed initially through committees set up within national (Institution of Lighting Professionals - ILP) and international (Commission International De L'Éclairage - CIE) organisations on which Principal Investigator Steve Fotios sits. These committees comprise representatives of lighting research, design, installation and manufacture, and are tasked with reviewing a wide range of evidence associated with road lighting. Guidance reports from these organisations will influence the next revision of BS5489-1, the critical document for road lighting in the UK.