Evaluering av tiltak for å redusere elgpåkjørsler på veg

Summary

English: This report was written for The Norwegian Public Roads Administration and is part of a larger project where the main goal is to summarize ungulate-vehicle accidents frequencies and injury statistics on road sections with and without remedial actions. In this report we have looked at the effects of different mitigative techniques that have been carried out to reduce the risk of moose-vehicle collisions. We have evaluated the effects of roadside clearing, intercept feeding, scent marking and wildlife reflectors by analyzing moose-vehicle accident data on selected road sections with a relatively high amount of moose-vehicle accidents before and after the remedial actions were carried out. The road sections used in this study include European highway 6 through Steinkjer, Grong and Namsskogan municipalities in Nord-Trøndelag county and Highway 3 and 25 through Elverum, Trysil, Stor-Elvdal and Rendalen municipalities in Hedmark county. The data material is based on registrations of moose-vehicle accidents positioned in time and space along the road sections of interest. As far as possible, variation in the number of vehicle accidents caused by other factors than remedial actions (e.g. climatic variations, population densities) was taken into account in the analyses. In addition we have analyzed the effect of winter climate and moose population densities on annual variations in the number of moose-vehicle accidents. Data on vehicle accidents registered at Statistics Norway (SSB) were used in these analyses. This includes registrations of accidents on all roads in the studied municipalities, but only occations were the animal was killed as a result of the collision. Winter length was used as an indicator of winter climate and data on harvested moose and observed moose by hunters were used to estimate annual variation in moose population density. Roadside clearing was the only remedial action that with a relatively high degree of certainty seemed to have had a reducing effect on the risk of moose-vehicle accidents. This effect was only present in Nord-Trøndelag county. A statistically significant effect of roadside clearing was only found in Grong municipality, but a similar tendency was present in Steinkjer municipality. There were no effects of roadside clearing present in Stor-Elvdal and Trysil municipalities, while it seemed to have had an increasing effect on vehicle accidents in Elverum municipality. The lack of reducing effects of roadside clearing might be explained by topographic features, lack of maintenance of the roadside clearing sections, width of the cleared sections and speed limits. We did not find statistical significant reductions in moose-vehicle accidents of either intercept feeding, wildlife reflectors or scent marking, but there was a tendency of a reduction after remedial actions on road sections with use of either scent marking or wildlife reflectors. There was also a tendency of reduced frequency of vehicle accidents with intercept feeding, but this could not be tested statistically. However, the lack of reducing effects of the remedial actions on vehicle accidents does not necessarily exlude the possibility that they had an effect. Most of the mitigative effort included in the analyses was carried out on a relatively small amount of road sections, most of the sections were of rather short lengths and several were only carried out in one or two seasons. All these aspects increase the uncertainty of the analyses and reduce the probability of detecting statistically significant differences. In addition there were several elements of uncertainty about the quality of the raw data. This was due to 1) unknown accuracy of the mapping of moose-vehicle accidents, 2) uncertainty about whether all accidents had been registered, 3) unknown accuracy of the mapping of remedial actions and 4) no exact information on when the remedial actions had ben carried out. In relation to roadside clearing there was also a lack of general information on how the procedures were carried out, such as the width of the cleared road sections and whether the whole section or only parts of the section were cleared. We did also carry out a new registration of positions of warning signs in both Nord-Trøndelag and Hedmark counties. In Hedmark our registrations agreed with existing information in the National Road Database. In Nord-Trøndelag, however, there were some deviations, both in relation to number and positioning of signs. This indicates that there might be room for improvement of the routines for updating the warning sign database. In the analyses of the effects of winter climate and population densities on annual variations in moose-vehicle collitions we found a positive relation between the annual number of accidents and winter length and moose population densities in both Hedmark and Nord-Trøndelag. In addition there was also a negative relation between winter length and the annual number of accidents in Nord-Trøndelag. The climatic conditions in Hedmark and Nord-Trøndelag are relatively different, and there might be that winter length is a better index of the effect of winter climate on moose movements in Hedmark than in Nord-Trøndelag. The road directory and the wildlife management need knowledge about the effects of remedial actions on ungulate-vehicle accidents and where these actions should be located. This acquires access to data on vehicle-ungulate accidents positioned in space and time and available high quality information on location, duration and procedures of the remedial actions. Furthermore, one should consider establishing studies with experimental designs to look at effects of remedial actions, and future efforts to carry out remedial actions should be coordinated across larger areas.