Where Are Idaho’s Deadliest Roads, and What Factors Contribute Most to its Fatal Accidents?

Out of Idaho’s 107,568 miles of road, MoneyGeek analyzed 310 roads to identify which were deadliest to drivers. Several factors contributed to the 640 fatal accidents in Idaho. MoneyGeek’s study looked closely at how four factors — winter conditions, drunk driving, speeding and distracted driving — contributed to deadly crashes. The study also broke down data county-by-county to determine the most dangerous roads there.

• I-84 between Ustick Rd. and Exit 29 is the deadliest stretch of road in Idaho.
• 30% of fatal accidents were related to drunk driving.
• Speeding contributed to 21% of accidents.
• Distracted driving was involved in 11% of accidents.
• The month of July had the most fatal accidents.
• Ada had more deadly accidents than any other county.

1. I-84 Between Ustick Rd. and Exit 29

Caldwell

SR-21 from E. Lake Forest Dr. to Highland Valley Summit

Boise

US-95 from S. McAvoy Rd. to E. Mica View Rd.

Coeur D Alene

I-84 from Exit 49 to Exit 42

Meridian | Boise

US-95 Between Sunnyside Rd. and Cox Rd.

Washington County

US-95 from E. Nez Perce Rd. to Hatwai Bypass

Nez Perce County

US-95 Between Exit 442 and Boekel Rd.

Kootenai County

I-84 Between Exit 188 and Exit 194

Jerome County

I-84 Between Exit 13 and Exit 9

Payette County

US-93 from E 100 S. to E 290 N.

Jerome County

From 2017 to 2019, drunk driving contributed to 30% of all fatal accidents in Idaho. That’s 189 out of 640 fatal crashes. Drunk driving was the primary contributor MoneyGeek studied — it was involved in more fatal accidents than speeding, distracted driving and winter conditions.

You're considered legally intoxicated in Idaho if your blood alcohol concentration (BAC) reaches 0.08%, but it takes very little for your driving to be impaired. A 0.02% BAC measurement is high enough to affect your driving ability, putting yourself and your passengers in danger.

Drunk driving comes with severe consequences outside of fatalities. A DUI conviction leads to less affordable car insurance in Idaho, license suspension, restricted driving privileges and jail time. It will also require you to carry an SR-22 in Idaho, which is more expensive than other types of coverage.

In three years, 136 fatal car accidents in Idaho involved speeding. That’s 21% of all fatal accidents recorded in the state between 2017 and 2019. Driving above the allowable speed limit makes controlling your car more difficult, especially when you need to stop suddenly for any reason. If you get into an accident, your speed increases the strength of impact, which can lead to severe injuries or worse — fatal crashes.

Distracted driving was a factor in 11% of fatal accidents in Idaho from 2017 to 2019. That’s 73 out of 640 accidents that ended with fatalities. MoneyGeek’s analysis showed Idaho to be the seventh-worst state for distracted driving. In July 2020, Idaho enacted a new distracted driving law that expanded its definition of distracted driving beyond texting to include other uses of gadgets such as browsing social media and watching or recording video.

MoneyGeek found that 12.7% — or 83 accidents — in Idaho happened in July. June had the second-highest number of lethal accidents with 75 (11.9%), and August third with 73 (11.4%). These months all fall within the state’s 100 Deadliest Days, the period with the most fatal accidents that spans from Memorial Day to Labor Day. Drunk driving was the most sizable contributing factor to fatal accidents in all three months.

Being a safe driver is an advantage in many ways. Not only do you make Idaho roadways less dangerous, but you may also pay fewer costs in the future. However, even the most careful drivers can be involved in auto accidents, so it’s essential to have proper insurance coverage.

An affordable full coverage car insurance plan is the best type of policy to carry for financial protection in Idaho. Because Idaho is a tort state, you’re obligated to shoulder the other driver’s medical and repair expenses if you cause an accident. A full coverage policy covers these damages and also protects you from costs incurred if you or your passengers suffer injuries, or your car is damaged.

The average cost of car insurance in Idaho is $745 per year for a full coverage policy. While auto insurance in Boise costs the same amount per year on average, note that the price of car insurance can vary depending on where you live in the state.

Policy rates are also affected by other factors such as your age, driving history or preferred coverage level. It’s best to compare quotes from multiple providers to help you find car insurance companies with the cheapest rates.

The top-five counties in Idaho with the most fatal accidents had 251 fatal crashes from 2017–2019. That's 39% of all recorded accidents that resulted in fatalities. Approximately 28% (70) involved drunk driving, 22% (54) speeding and 9% (23) distracted driving.

Of the 43 counties in Idaho, Ada had the highest number of fatal accidents in the three-year period at 78. Most of these happened along I-84 and involved drunk driving and speeding accidents.

MoneyGeek analyzed data from the National Highway Traffic Safety Administration FARS (fatal accident reporting system) database using fatality data from 2017, 2018 and 2019. Currently, 2019 is the latest data available in the system.