Background Along with structural changes in agriculture, increasing area of arable land and the number of field parcels on a farm are exceedingly raising the movement of agricultural equipment on public roads. At the same time also the sizes of agricultural vehicles are growing. Traffic accidents involved agricultural vehicles often lead to serious injuries or even death.

Methods In order to find out the present situation in traffic accidents and to improve the traffic safety with slow-moving agricultural vehicles, national statistical information of road accidents 2004–2013 and of occupational accidents in agriculture 2004–2014 were gathered. In addition, an enquiry of road accidents, near accidents and safety measures (good practices) was sent to large farms. In order to find out how much time is spend and how many kilometres are driven on public roads by a farm tractor on a large farm, two tractors on two farms were followed by AgriSmart GPS system during a growing season.

Results For results about 6 300 roads accidents are analysed. Most often the agricultural party was a tractor and the other party a passenger car, as reported also in previous studies. The speed limit of the road was at least 80 km/h in more than half of the accidents (54%). Turning accidents were the most common type of these accidents. More than 20% of respondents of the enquiry had had at least one road accidents with slow-moving agricultural vehicles during the last 10 years. The most serious accidents occurred on main roads where variations in vehicle velocities are the largest. The farms have put into practice several measures - most often technical like extra lights, flashing lights and wide private crossroads – to improve traffic safety. According to the first half of the follow-up period of the two tractors, the tractors were used on roads about 20% of the time.

Conclusions Wide variations in vehicle velocities and poor ability to recognise slow-moving agricultural vehicles are crucial risk factors in agricultural traffic. Various measures are needed to reduce traffic accidents involved slow-moving agricultural vehicles. These should be focused on agricultural machinery, roads, farmers and other road users. This on-going study is financed by the Farmers’ Social Insurance Institution and the Finnish Research Fund of Agricultural Machinery.