It's getting to be that time of year again -- summer's coming, folks are heading out to national parks, and wildlife are losing their lives to collisions with vehicles.

With Memorial Day Weekend kicking off the summer travel season, Grand Teton Natonal Park officials are urging motorists to take care when driving park roads so as not to run over animals. Each year, motor vehicles cause the deaths of well over 100 animals in the park, resulting in a significant toll to wildlife, says Grand Teton spokeswoman Jackie Skaggs.

Over the past few years, park rangers and biologists have documented trends related to wildlife-vehicle collisions in an attempt to make park roads safer for both people and animals. Here's what they found:

Since 2000, the number of animals killed on park roads has steadily increased. In fact, a 31 percent rise in wildlife-vehicle collisions occurred between 2008 and 2010. While an average of 104 animals are killed annually on park roads, an unparalleled 162 vehicle-caused deaths were tallied in 2010 alone. Included in the 2010 data were 48 elk, 41 deer, 17 bison, six pronghorn, five moose, five bears, and two wolves. Park biologists believe this tally is likely higher as some collisions are never reported. This unprecedented increase in vehicle-caused wildlife deaths came despite a proactive education/prevention campaign launched in 2006.

Records of wildlife-vehicle collisions indicate certain trends and patterns. Statistics show that most of the accidents occurred between dawn and dusk along Highway 26/89/191 between Moose and Moran junctions where the speed limit is posted as 55 mph. A number of collisions also occurred between the Gros Ventre River Bridge and Jackson Hole Airport Junction. Drivers involved in wildlife collisions were almost equally as often local residents as they were out-of-state visitors; most commonly the drivers were males traveling alone or with one passenger. Speed was often the biggest factor in these collisions, particularly at night when drivers exceeded the range of their headlights. Motorists who overdrive their high beams—when the stopping distance is greater than the headlight illumination distance—are less able to stop or slow down with a sudden appearance of an animal on the road. Drivers are cautioned to observe posted speed limits and even reduce their speed—especially at night.

Park managers plan to implement new prevention measures in an effort to reverse the recent trend in animal deaths from vehicle collisions, Ms. Skaggs said in a release. Flashing message boards will be placed at various wildlife crossings and collision hotspots; and stationary signs will be posted at seasonally active areas.

In addition, the speed limit on Highway 26/89/191 will be reduced to 45 mph from the park’s south boundary to Moose Junction while construction of the multi-use pathway is under way. During this same time, park staff will closely monitor wildlife-vehicle collisions to determine if there is a related decline in animal deaths. Data collected will inform future decisions about possible actions that can be taken to control traffic, such as seasonal speed limits to slow vehicles during wildlife migrations on Highway 89 in Grand Teton National Park. Rangers might also increase patrols to educate motorists about being alert for wildlife and enforce speed limits.

Grand Teton's roads wind through expansive sagebrush flats—and through some of best habitat in the country for elk, deer, bison, pronghorn, moose and bears. The same conditions that make Grand Teton a global destination for wildlife-viewing also make it a challenge for wildlife-vehicle collisions as animals regularly cross and travel near park roads. Park officials remind motorists to stay alert, slow down and give wildlife a break—especially during low-light conditions from dusk to dawn when animals may be difficult to see. Drivers should expect the unexpected with regard to wildlife that travel near and across park roads.