Floating Car Road Weather Information Monitoring System

Adverse weather conditions are a significant problem in traffic safety in Finland. Almost half of winter accidents occur during bad road conditions. Road users are not always aware of the road conditions and risk when driving in winter. In Finland telematics solutions are used to decrease negative effects of the difficult road weather conditions to the traffic safety. Finnish National Road Administration has chosen the 350 km-long E18 road running from Turku on the south-west coast via Helsinki to the Russian border to be a test area for weather related traffic management telematic solutions. One of the tested solutions was floating car road weather information monitoring system.

At the moment, Finnra's traffic management system makes use of Finnra’s road weather information system (RWIS) with its over 250 outstations, 50 road conditions monitoring videocameras as well as satellite and radar pictures from the Finnish Meteorological Institute. On the E18, thermal mapping has been done for the whole test road section. Traffic conditions are currently monitored with the help of 200 automatic traffic counting stations. The conditions on the corridor are monitored in real time. Traffic flows and weather conditions are monitored at permanent stations spaced at on 20-70km intervals.

Extensive use is made of data collected by vehicle moving along the corridor. This "floating car" concept produces data on road weather conditions as well as video pictures from every part of the corridor. The collected data are transferred in real time to Finnra’s regional traffic information centers. The measuring vehicle has been developed to improve the scope and exactness of the weather information. With a vehicle it is possible to measure the temperature and moisture of air, the temperature and friction of the road surface and the GPS (Global Positioning System based on the satellites) co-ordinates of the measuring time during the normal driving. The information is sent real-time to the Finnra’s road weather information system using the GSM (cellular phone) net.

The reliability and the technical functioning of the equipment that has been developed for the moving road condition monitoring have been tested with different studies and tests. The general technical functionality of the system is good. The measurement system and the transmission of information to the road weather information system function reliably. The measurement results of weather information measured with the moving vehicle are very near of the results of the fixed road weather monitoring stations. The repeatability of the friction measuring is good. The exactness of the friction measurement seems to be good enough for information purposes, not for exact studies. The video measuring equipment must be developed further.