A sweeping national analysis from Sweet James reveals a troubling pattern: summer conditions are rapidly transforming America’s highways into high‑risk corridors for commercial truck drivers. Rising temperatures, extreme UV exposure, mechanical failures, and elevated crash totals converge to create a season of heightened danger for the country’s freight workforce. As climate trends accelerate, the data shows that truckers face escalating threats to their health, safety, and long‑term well‑being.
This rewrite examines the study’s findings through a newsroom lens, focusing on the measurable impacts of extreme heat, the geographic distribution of crash risk, and the human consequences of prolonged exposure to hazardous summer conditions.
Extreme Heat: A Growing Threat to Truckers
Extreme heat is one of the deadliest weather‑related hazards in the United States, contributing to more than a thousand deaths annually. For truck drivers, the risks are amplified by long hours, heavy equipment, and exposure to both environmental and in‑cab heat.
Mechanical Failures Under Heat Stress
The study outlines several mechanical issues that intensify during heatwaves:
- Engine overheating
- Tire blowouts
- Brake degradation
- Battery failure
- Fuel system complications
- Cooling system breakdowns
These failures can lead to roadside emergencies, delivery delays, and increased crash risk. Regular maintenance becomes essential, yet even well‑maintained trucks struggle under prolonged extreme temperatures.
Rising Climate Temperatures
U.S. temperatures continue to climb. May 2025 averaged 61.7°F — 1.5°F above the 20th‑century baseline. Some regions may see summer increases of up to 6°F, creating conditions that strain both drivers and vehicles.
Human Impact: Injuries, Illnesses, and Fatalities
Heat affects more than machinery — it affects the human body. Between June and August in recent years, truck crashes consistently exceeded 19,000 per month, with fatalities surpassing 1,600.
Heat‑Related Injury Trends
A 2025 analysis of 845,014 OSHA‑reported injuries found:
- Injury risk increases at 85°F
- Risk rises sharply above 90°F
- Even moderate heat (70°F+) contributes to workplace injuries
- Transportation and warehousing workers are among the most affected
Freightwaves data shows a 5–6% increase in trucker injury rates when temperatures exceed 90°F.
Cognitive Decline and UV Exposure
Heat impairs cognitive performance, slowing reaction time and decision‑making. Several consecutive days above 95°F can significantly reduce mental sharpness.
UV exposure is another major hazard. Truck drivers experience:
- 5× more UV exposure on the left arm
- 20× more UV exposure on the left side of the face
This imbalance leads to premature aging, skin damage, and elevated cancer risk. A documented case of unilateral dermatoheliosis in a long‑time driver illustrates the severity of prolonged exposure.
UV Irradiance Rankings
The study ranks states by average daily UV exposure:
| Rank | State | UV Irradiance (J/m²) |
|---|---|---|
| 1 | Arizona | 4,931 |
| 2 | New Mexico | 4,797 |
| 3 | Hawaii | 4,793 |
| 4 | Florida | 4,596 |
| 5 | California | 4,541 |
Low‑exposure states include Alaska, Vermont, New Hampshire, Maine, and Massachusetts.
Personal Injury Cases Highlight Heat’s Consequences
The study includes several cases demonstrating how extreme heat contributes to catastrophic outcomes:
- A Texas UPS driver collapsed and later died after working in high temperatures.
- A New Mexico tire failure lawsuit resulted in a $220 million verdict after a heat‑related crash killed three people.
- A 2025 lawsuit alleges that GM brake master cylinders fail prematurely due to under‑hood heat exposure.
These cases underscore how rising temperatures intersect with product design, maintenance standards, and employer responsibility.
UPS Case Study: Heat Inside Delivery Trucks
Sweet James’ analysis includes a detailed look at UPS drivers, who have long reported extreme heat inside delivery trucks.
Key Findings
- Cargo areas often run 20–25°F hotter than outside air
- Temperatures have been recorded as high as 152°F
- Between 2015 and 2022, at least 143 UPS employees were hospitalized for heat‑related injuries
- Drivers report dizziness, blurred vision, vomiting, and kidney failure
UPS has pledged to add 28,000 air‑conditioned trucks by 2028 and retrofit 5,000 more. However, union representatives say progress has been slow.
Weather‑Related Crash Data
The study analyzed 235,023 weather‑related truck crashes between 2022 and 2026.
Crashes by Weather Condition
| Weather | Fatalities | Crashes |
|---|---|---|
| Clear | 16,447 | 190,429 |
| Rain | 1,280 | 18,323 |
| Other | 805 | 8,186 |
| Snow | 272 | 4,804 |
| Fog/Smog/Smoke | 305 | 2,235 |
| Severe Winds | 49 | 810 |
Clear, warm days — not storms — produced the highest crash totals.
Crashes by Road Condition
| Road Condition | Fatalities | Crashes |
|---|---|---|
| Dry | 17,202 | 195,410 |
| Wet | 2,157 | 28,686 |
| Slush/Snow | 303 | 5,131 |
| Ice | 265 | 3,653 |
Dry roads dominate crash statistics, contradicting assumptions that icy conditions are the primary threat.
Regional Crash Hotspots
Southern and Midwestern states recorded the highest crash rates per capita in 2025.
Highest Crash Rates (per 100k residents)
| Rank | State | Rate |
|---|---|---|
| 1 | Arkansas | 78.56 |
| 2 | South Carolina | 78.29 |
| 3 | Missouri | 76.64 |
| 4 | Georgia | 75 |
| 5 | Indiana | 71.65 |
Lowest Crash Rates
| Rank | State | Rate |
|---|---|---|
| 1 | Alaska | 2.03 |
| 2 | Hawaii | 6.5 |
| 3 | Rhode Island | 9.89 |
| 4 | New York | 16.43 |
| 5 | Massachusetts | 19.37 |
Fatality rates follow similar regional patterns, with South Dakota, Oklahoma, and Nebraska topping the list.
Conclusion
Sweet James’ study shows that summer trucking is becoming increasingly hazardous. Rising temperatures strain vehicles, impair drivers, and elevate crash risk across the country. As climate trends accelerate, the industry faces mounting pressure to adapt through better equipment, stronger safety protocols, and improved driver protections.
