Monitoring winter road friction using floating car data

Abstract: Every year more than a million people are killed due to road traffic accidents globally, were one of five serious or fatal accident occurs during severe weather conditions. Sweden is in the lead of Vision Zero, with the aim of zero casualties due to road traffic, and every year new countries and organisations accepts the challenge of saving lives. Early studies have shown that one way of decreasing casualties is to implement floating car data (FCD), and one example of such an implementation is to gather knowledge about the current state of the road network enabling targeted winter road maintenance. By implementing FCD for winter road maintenance, besides creating safer roads, savings will be made for the environment reducing the use of fossil fuels and salt.Since the fleet of vehicles are going towards being fully autonomous, the volumes of FCD will increase rapidly generating new possibilities of FCD usage. Recent research regarding FCD has mainly been focused on traffic flow, speed and route optimisation, together with general methods for FCD mining creating intelligent transport systems. Studies have also been made for covering the gap between road weather information systems (RWIS) monitoring the road condition and thereby improving road weather forecasts. But there is a need of research regarding implementation of FCD at a level of action, closer to the road users improving winter road maintenance.Presented in this thesis are results gathered in the project Digital Winter, a project initiated by the Swedish Traffic Administration, were FCD regarding tire-to-road friction has been procured for all public roads in Sweden. Results shows promising numbers regarding coverage and reliability for implementation of FCD for winter road maintenance follow-up, managing that assigned levels of road friction is achieved. Examples are given for different areas in Sweden where harsh weather conditions are detected and statistics shows a coverage of FCD both at a daily and hourly level. Multiple suppliers of FCD have been participating in Digital Winter and the reference measurements presented, shows a correlation between suppliers of FCD and methods that today are approved for winter road maintenance follow-up in Sweden.