Bear crossing sign in the Huron-Manistee National Forests, Michigan, USA (Tonu Faiola – Creative Commons Licence)


Roads and railways are a source of both direct and indirect mortality for bears. Whilst a number of bears are killed after being in collision with a motor vehicle or train, many more die because of the adverse, indirect effects of roads and railways.

Direct fatalities – Rail

Rail-related bear fatalities have a number of causes.  The most common causes are well illustrated by the experience of the Canadian Pacific Railway in Canada, particularly in the provinces of British Columbia and Alberta.  There bears use train tracks as a travel route, as a place to feed on grain spillages from trains and also as an access point to trackside foodstuffs such as berries and plants.

As with roads (see below) bears are also attracted to railways by the presence of grasses, other plants and berries, and by the carcasses of other animals which have been killed by trains.

Direct fatalities – Road

As more roads are built in bear-country and traffic volumes and speeds increase on existing roads, bear fatalities also increase.  In order to move from one part of their territory to another, bears need to cross roads.  If they choose the wrong moment to do this the end result can be a damaged vehicle and a dead or fatally injured bear.

As well as needing to cross roads, bears are often drawn to them by a number of attractants, both natural and unnatural.  Amongst the former are roadside vegetation such as grasses, dandelions and berries; open areas alongside roads are especially attractive to bears in the spring because snow melt occurs earlier there.  Carcasses of previously killed animals (mainly ungulates) on the roadside also attract bears.

Unnatural attractants include spilled grain (as on railways, see above), tourists who feed bears and other animals, and litter left on the roadside by passing motorists and truck-drivers.

Indirect fatalities

Roads and railways indirectly lead to bear deaths through the provision of access to hunters, poachers, settlers, tourists and industry.  Each of these groups are potentially lethal to bears.

Bears who feed alongside roads are highly exposed to humans and this can lead to human habituation and food-conditioning leading to the associated risk to bears of removal or of being killed as a risk to human safety.

 Reducing the effects of roads

There are a number of steps which can be taken to reduce the likelihood of bear- vehicle collisions.  Whilst these include the provision of wildlife crossings (see photograph below) and the removal of road-kill from the roadside, they are mainly aimed towards the human visitors to bear-country:

  •  Reduction in speed limits and the introduction of night-time speed limits together with enhanced enforcement
  •  Where there is a dual carriageway, the regular removal of central reservation vegetation
  •  Variable electronic roadside message signs, including but not limited to speed radar “slow down” warnings
  •  Marking of fatality sites (“red bear, dead bear”)
  •  Traffic calming measures at fatality “black spots”, including road narrowing, speed humps and rumble strips
  •  Education to increase bear-awareness in parks, reserves and other areas of bear habitat coupled with increased ranger and/or police patrols of highways and byways.

Wildlife overpass on the Trans-Canada highway in Banff, Alberta (Qyd – GNU FDL)

Reducing the effects of railways

Strategies to reduce bear-train collisions include the reduction of grain spillage onto tacks, the review of infrastructure and operating procedures to allow bears longer to evade trains, fencing and crossing points to keep them away from the track, management of lineside vegetation to improve sightlines and/or enhance sound transmission and to create attractive offsite habitat for bears

On the Canadian Pacific efforts to reduce grain spillage include a $20 million gate refurbishment and replacement program for 6,300 rail cars, and sill cleaning program.  Other initiatives include testing of bells, lights and horn by train crews, whistling in high-risk areas, testing of wildlife exclusion systems such as the bear boards used in conjunction with the perimeter fencing around the Lake Louise town site and more recently the use of on-board locomotive camera systems to record collision events.


“Effect of traffic volume on American black bears in central Florida, USA” (Ursus 2009). Click here for PDF.

 Bears to get no help crossing this SC coastal road (August 2015)

 Canadian Pacific Bear Conservation Initiative (Canadian Pacific website)

Road safety for wildlife: researchers analyze the best techniques for road-kill mitigation (July 2017)

Roads to trouble: killing wilderness and bears (Grizzly Times website)




Grizzly bears in Banff are endangered by trains, but remarkable efforts are being made to keep them safe.

Page updated 16 February 2021