Deer Vehicle Accidents: How Many Really Occur in CT?

Written by Howard Kilpatrick, DEP Deer/Turkey Program Supervisor

A collision between a deer and a vehicle, especially at high speeds, can be dangerous and costly. The frequency and distribution of deer-vehicle accidents, along with many other indices, are used by the DEP Wildlife Division to identify areas where deer populations may be too high. When a state, local, or DEP law enforcement officer responds to the scene of a deer-vehicle accident and observes a dead deer, a Deer Kill Incident Report (DKIR) is completed and submitted to the Wildlife Division. The Division uses DKIRs to keep track of how many deer are killed by vehicles along Connecticut roadways. Reports of deer-vehicle accidents have continued to climb, from just over 500 in 1975 to around 3,000 in 2000. Recent reports indicate that the number of roadkilled deer has remained relatively stable.

To assess how many deer are being killed by vehicles but are not reported, the Wildlife Division initiated a study comparing three data sets for deer-vehicle accidents. The first data set was the number of reported vehicle- killed deer, based on DKIRs submitted by law enforcement officials to the DEP. The second data set was the number of dead deer retrieved from roadways by the Connecticut Department of Transportation (DOT). This data set included all dead deer found on roads (dead deer reported and not reported by law enforcement officials). The third data set was the number of deer-vehicle accidents that the Connecticut State Police responded to, regardless of whether a dead deer was found at the scene of the accident.

First, the data from DKIRs (reported vehicle-killed deer) was compared to DOT data (reported and unreported vehicle-killed deer). It was found that for every one deer reported by law enforcement officers on DKIRs, five additional deer were hit and killed by vehicles but not reported to law enforcement officers. Secondly, the number of deer-vehicle accidents that the State Police responded to was compared to the number of dead deer that were reported at the scene of each accident. It was found that for every one deer found dead at an accident, three additional deer were hit by vehicles but could not be confirmed as dead or alive.

In summary, although 3,000 deer are reported killed by motor vehicles on Connecticut roadways, a more realistic estimate would be that about 18,000 deer are killed annually. This is equivalent to about 49 deer per day being killed on state roadways. Also, for every one deer reported dead, three additional deer are hit by vehicles and their fate is unknown. This study clearly demonstrates that the risk of being involved in a deer-vehicle accident is much higher than previously assumed. Connecticut Wildlife