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At least 7,497 animals were killed on Colorado roadways last year, with deer accounting for the vast majority.

This is according to the latest roadkill data from the Colorado Department of Transportation. The agency relies on reports from its road maintenance crews and roadkill app as well as an to gather quarterly and annual roadkill reports for the state. 

The counts come with a caveat that the numbers are underreported and can have inequalities regarding where reports are made.

While the department warns that these numbers are intended for information only, they provide a glimpse of which animals are being struck where.  

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What can the data tell us about wildlife-vehicle collisions? 

The data shows that the further west you go in the state, the more roadkill is reported.

Last year, the Colorado Department of Transportation’s southwest region — in the state — had the highest volume of reported roadkill. The region reported that 2,545 animals were killed, nearly 34% of the state’s total. 

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This is followed by the state’s northwest region, which had 2,095 reported animals, or around 28% of the total in the state. 

The northwest region encompasses a significant portion of the Western Slope including Moffat, Routt, Jackson, Grand, Summit, Eagle, Lake, Pitkin, Rio Blanco, Garfield, Mesa, Delta, Gunnison and Hinsdale counties. It also includes a portion of Montrose County.

According to the data, December was the deadliest month for the state and both western regions in 2024. For the northwest, this was followed by November, March and October. In the southwest, October, November and July followed behind December.   

In 2024, 991 animals were reported as roadkill in Colorado in December, exceeding the highest month in 2023 by around 30 reports. April was the deadliest month in 2023, bolstered by a reported 500 animals killed in the northwest region that month. While the department acknowledges this number appears to be unusually high, CDOT reported it was “double-checked and appears to be correct.”

What animals are being struck in Northwest Colorado? 

Across the state, mule deer accounted for around 60% of the reported roadkills in 2024 — topping the list of wildlife in all five of the department’s regions. 

In the northwest, deer made up 56% of the roadkill reported, hitting a high in November with 179 animals counted.  

While the roadkill reports provide a snippet of information on the deadliest highways for animals, the state agency notes that it should only be used to study the same stretches of road over time. Many of the stretches with high numbers of incidents last year were among the highest-risk areas named in a .

Interstate 70 — running from the eastern border of Summit County to the Utah border in the region — had the highest number of deer roadkill reports in 2024. Of the deer reported in the northwest, 15% were found on this roadway. The 10-mile stretch spanning from the county line between Garfield and Eagle counties to Gypsum in Eagle County had the most reports on I-70. 

U.S. 40 — which, in the northwest, runs from the Utah border near Dinosaur and traverses to the border of Grand and Clear Creek counties — was the second-deadliest roadway for deer, accounting for 14% of those reported in the region. A 10-mile stretch in Moffat County had the most reports on this roadway. 

For deer, it was U.S. 50 — stretching from Mesa County and traversing Delta and Gunnison counties in the region — that had the third most reports. A 20-mile stretch in Gunnison County accounted for 71% of the reported deer kills in 2024 on the road. 

Elk trailed behind deer as the second-highest animal to be struck last year in the northwest, accounting for 11% of all roadkill. The highest numbers were reported in December, with 21% of all elk reports taking place in the final month of the year. 

The reports were fairly even in number across all the region’s roadways with only four, 10-mile stretches of highway reporting 10 or more elk deaths. This includes a stretch on Colorado Highway 9 in Summit County and Colorado Highway 82 from Snowmass to Aspen as well as two portions of U.S. 50 in Gunnison County. 

Deer and elk have historically been reported as the primary roadkill targets across Colorado. In a letter accompanying the 2024 roadkill data, Jeff Peterson, CDOT’s wildlife program manager, noted a slight shift between 2023 and 2024 as statewide deer and elk reports declined 0.8%. 

“While not huge, the numbers are going down despite more traffic on the roads,” Peterson wrote, adding that he hopes it is the start of a downward trend and increasing numbers of wildlife crossings being built. 

Bears were the third-most reported roadkill in the northwest region last year with 97 reported. Overall, bears made up nearly 5% of the region’s roadkill, the highest in the state both in percentage and county. There were reports in every month from May to November, spiking in August with 36 bears reported dead. 

This aligns not only with the months that bears are awake in Colorado but also the spike aligns with when Parks and Wildlife historically receives the highest number of bear sightings and conflict reports. These reports are typically the highest in northwest Colorado. While it has yet to release its monthly data for 2024, the state wildlife agency reported the most conflict in July, June and August of 2023.    

For bears, I-70 was reportedly the deadliest roadway in the region, with 50% of all roadkill for the species reported on the interstate. This was followed by Highway 82, which accounted for 27% of the bear reports.  

With a few exceptions, deer, elk and bears were the only animals that exceeded 10 reports in a month for that species in the northwest. The largest exception is unknown animals, of which 23 were reported on average each month in 2024. The second exception is raccoons: 20 were reported in September and 13 in November. 

A growing movement to prevent wildlife-vehicle collisions

Wildlife-vehicle collisions were the sixth-most common type of crash in 2024, according to . Last year, these collisions were behind just over 2,700 vehicle incidents. 

Peterson wrote that “interest in wildlife-vehicle collisions and crossings continues to grow” in his letter to wildlife-vehicle collision stakeholders — predominantly members of Colorado’s transportation and natural resources departments. 

As the transportation agency and Parks and Wildlife work to increase reporting of roadkill, the picture is becoming clearer. This makes goals of lowering the number of collisions and building wildlife migration corridors more possible to achieve, Peterson added.

Amid statewide efforts, northwest Colorado has seen growing momentum to create safe passages for wildlife in the last decade. Bolstered by the success of the passages built on Highway 9 south of Kremmling in 2016, are among those in the state seeking funding to build infrastructure for wildlife.