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Providing evidence to improve practice

Individual study: Evaluation of 2.4 m fences and one-way gates for reducing deer vehicle collisions in Minnesota

Published source details

Ludwig J. & Bremicker T. (1983) Evaluation of 2.4 m fences and one-way gates for reducing deer vehicle collisions in Minnesota. Transportation Research Record, 913, 19-22


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Install one-way gates or other structures to allow wildlife to leave roadways Terrestrial Mammal Conservation

A replicated, before-and-after study in 1977–1979 along two highways in Minnesota, USA (Ludwig & Bremicker 1983) found that barrier fencing with one-way gates decreased deer-vehicle collisions. Along two fenced road sections, 1.3 and 8 deer/year were killed compared to an estimated 20/year in the pre-fence period. One fence was installed in a ditch with 1 m of water, meaning 30% of gates could not be used to escape the highway. Overall, 69% of 51 passages through gates were in the correct direction, i.e. from the highway to outside the fenced corridor. Two sections of 2.4-m-high fence with one-way gates along new highways were monitored for 18 months. Fences were 4 and 5 km long with nine and 10 pairs of gates (30 m apart), respectively. Deer were monitored crossing through gates by using baler counters and track beds. Deer-vehicle collisions were monitored for one year before (along old adjacent highway) and 18 months after installation. Cost-benefit analysis was also carried out (see the original article for further details).

(Summarised by Rebecca K. Smith)

Install barrier fencing along roads Terrestrial Mammal Conservation

A replicated, before-and-after study in 1977–1979 along two highways in Minnesota, USA (Ludwig & Bremicker 1983) found that barrier fencing with one-way gates decreased deer-vehicle collisions. Along two fenced road sections, 1.3 and 8 deer/year were killed compared to an estimated 20/year in the pre-fence period. One fence was installed in a ditch with 1 m of water, meaning 30% of gates could not be used to escape the highway. Overall, 69% of 51 passages through gates were in the correct direction, i.e. from the highway to outside the fenced corridor. Two sections of 2.4-m-high fence with one-way gates along new highways were monitored for 18 months. Fences were 4 and 5 km long with nine and 10 pairs of gates (30 m apart), respectively. Deer were monitored crossing through gates by using baler counters and track beds. Deer-vehicle collisions were monitored for one year before (along old adjacent highway) and 18 months after installation. Cost-benefit analysis was also carried out (see the original article for further details).

(Summarised by Rebecca K. Smith)