the same time, there was a large increase in deaths caused by vehicles along the new road; there had been none in the preceding six months. The vast majority of deaths occurred in the sealed portion of the road, believed to be due to an increase in speeds. It was also conjectured that the animals were harder to see against the dark bitumen instead of the light gravel. The devil and quoll are especially vulnerable as they often try to retrieve roadkill for food and travel along the road. To alleviate the problem, traffic slowing measures, man-made pathways that offer alternative routes for devils, education campaigns, and the installation of light reflectors to indicate oncoming vehicles have been implemented. They are credited with decreases in roadkill. Devils have often been victims of roadkill when they are retrieving other roadkill. Work by scientist Menna Jones and a group of conservation volunteers to remove dead animals from the road resulted in a significant reduction in devil traffic deaths. It was estimated that 3,392 devils, or between 3.8 and 5.7% of the population, were being killed annually by vehicles in 2001–04. In 2009, the Save the Tasmanian Devil group launched the "Roadkill Project", which allowed members of the public to report sightings of devils which had been killed on the road. On 25 September 2015, 20 immunised devils were microchipped and released in Narawntapu National Park. By 5 October 4 had been hit by cars, prompting Samantha Fox, leader of Save the Tasmanian Devil, to describe roadkill as being the biggest threat to the Tasmanian devil after DFTD. A series of solar-powered alarms have been trialled that make noises and flash lights when cars are approaching, warning the animals. The trial ran for 18 months and the trial area had two-thirds less deaths than the control. Devil facial tumour disease First seen in 1996 in Mount William in northeastern Tasmania, devil facial tumour disease (DFTD) has ravaged Tasmania's wild devils, and estimates of the impact range from 20% to as much as an 80% decline in the devil population, with over 65% of the state affected. The state's west coast area and far north-west are the only places where devils are tumour free. Individual devils die within months of infection. The disease is an example of transmissible cancer, which means that it is contagious and passed from one animal to another. This tumour