Deer Mating Season and the Unexpected Drop in Car-Deer Accidents

by Warren Seah


In various parts of North America, deer are exhibiting restlessness and recklessness as they embark on their mating season. While this is an exhilarating time for these ungulate creatures, it poses a cautious period for commuters who are already grappling with changes in daylight saving time.

A Puzzling Phenomenon

Auto insurers have observed a recurring trend where the rate of deer strikes reaches its peak in November. However, this year, insurance companies are closely monitoring the situation due to a significant drop in car-deer accidents reported last year.

The Unexplained Decline

The Insurance Institute for Highway Safety (IIHS), a car safety lab backed by a consortium of insurance companies, possesses a comprehensive database of crash data. According to the IIHS researchers, they have identified the underlying factors behind most deer strikes. Interestingly, they found that in 2019, the frequency of animal strike claims was 14.1 claims per 1,000 insured vehicle years. However, this figure decreased to 12.6 claims per 1,000 insured vehicle years in 2020.

The Impact of the Pandemic

The root cause of the decline in car-deer accidents during 2020 can be attributed to the ongoing COVID-19 pandemic. While the deer were most likely following their usual patterns, human behavior shifted. With fewer drivers on the roads during the crucial dawn and dusk periods when deer are most active, the number of deer strikes naturally decreased. It’s important to note that these ungulates are crepuscular animals, which means they are primarily active during twilight periods.

A Return to Normalcy

According to the institute, driving habits started to normalize in 2021 as Americans gradually resumed their regular routines. Consequently, claim frequency for deer strikes rebounded to approximately the 10-year average, resulting in 13.6 claims per 1,000 insured vehicle years.

An Unexpected Plunge

Despite the anticipated return to typical conditions, last year saw an unexpected plunge in the number of car-deer accidents. In November, the claim frequency dropped to 11.9 per 1,000, which was even lower than during the peak periods of lockdown.


As we navigate through deer mating season, it is crucial for drivers to remain vigilant on the roads. While the exact reasons behind the fluctuations in car-deer accidents remain somewhat mysterious, understanding the behavior of these majestic creatures can help mitigate potential risks.

Car crash experts scratching their heads

Insurers are puzzled by a recent phenomenon. According to Matt Moore, senior vice president of the Highway Loss Data Institute (the number-crunching arm of the IIHS), “This is a real head-scratcher.” The reason behind the decrease in deer-related car accidents remains uncertain. There are a couple of potential explanations, including changes in commuting patterns due to remote work and variations in the data.

One possibility is that newer automatic emergency braking systems, particularly those designed to prevent pedestrian crashes, may also be effective at preventing collisions with animals, such as deer. However, the IIHS expresses skepticism about this theory. These systems are relatively new and not yet widespread. Additionally, IIHS research suggests that they don’t perform as well in low-light situations where deer strikes are most common.

Another factor that could contribute to the decline in deer accidents is the use of high-tech headlight systems that can adjust and illuminate corners. However, researchers note that there hasn’t been a significant change in the U.S. fleet’s headlights between 2021 and 2022.

Contrary to any assumptions that there are fewer deer in the vicinity, the IIHS reports that state wildlife departments generally believe that deer populations are stable or increasing, especially in urban areas.

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Be extra careful this time of year

While last year’s decrease in deer-related accidents remains a mystery, it is crucial for drivers to remain cautious. Insurers advise drivers to reduce their speed when traveling through wooded areas during this time of year. It’s also essential to use high beams whenever possible and bear in mind that deer often move in groups. If you encounter one deer crossing the road, assume that several more may follow. In the event that a deer freezes in front of your vehicle, it is safer to apply hard braking rather than swerving.

This story originally ran on KBB.com_.

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