Safety assessment of local cooperative warnings and speed limit information

The study was designed to assess the impacts of cooperative intelligent transport systems (C-ITS) on traffic safety. The aim was also to review assumptions made in some previous studies and verify or update the earlier safety estimates. Seven informative C-ITS services warning about various situations and hazards were selected in the study. The expert estimates provided were grounded on new evidence about driver behaviour, the crash categories created in the European Risk Calculation tool (ERiC), and literature. The C-ITS services were assessed to reduce the number of fatalities and injury crashes. The clearly biggest drop in fatalities was assessed for ‘In-vehicle signage, speed limit’, ‘Weather warning’ being the second most effective. The next effective were assessed to be ‘Warning of emergency braking ahead’ and ‘Road works warning’. The smallest but still positive impacts were assessed for ‘Traffic jam ahead warning’, ‘Car breakdown warning’ and ‘In-vehicle signage, child and pedestrian crossing ahead’. Generally, the effectiveness was assessed to be somewhat smaller for injury crashes than fatalities. The authors conclude that the results are positive both for implementing C-ITS services as such and as supporting measure for the deployment of more intervening ITS and automated driving.