Elephants roaming onto northern Indian roads have led to the overnight closure of a key highway in Uttarakhand state over safety concerns, dpa quoted officials as saying Thursday. Herds have been blocking traffic on the road between the state capital, Dehradun, and the yoga and pilgrimage town of Rishikesh during the past few weeks, forestry official Dinesh Kumar said. Wildlife experts said increased traffic on roads that often cut across forest and elephant reserves have led to a rise in elephant-human conflicts as traditional elephant paths are blocked. Dense fog in the area also increased chances of encounters with the elephants, Kumar said. The district plans to divert traffic for a week from 6 pm to 6 am to a longer route, a police spokesman said. Motorists have been asked to drive carefully on that road, which borders national parks, and avoid early morning walks, he said. Park deforestation, poaching and encroachment by villagers is either boxing in the country's more than 26,000 wild elephants or causing them to stray from their habitat and reserves. A national government elephant task force set up in 2010 recorded at least 400 people and more than 100 elephants are killed every year in encounters between elephants and humans.