Under the Summer Sun: A Data Investigation Into America’s Rising Trucking Risks

A new national analysis from Sweet James reveals a stark reality: summer is becoming the most dangerous season for America’s commercial truck drivers. As temperatures rise, so do mechanical failures, heat‑related illnesses, and crash totals across U.S. highways. The data paints a picture of a workforce pushed to its limits by extreme weather, aging infrastructure, and long‑standing safety gaps.

This rewrite examines the study’s findings through a journalist’s lens, focusing on the intersection of climate trends, roadway conditions, and driver health. It also highlights the broader implications for freight movement and public safety.

The Heat Factor: Why Summer Is a Threat Multiplier

Extreme heat is one of the deadliest weather‑related hazards in the United States, contributing to an estimated 1,300 deaths annually. For truck drivers, the risks multiply due to prolonged exposure, heavy equipment, and long hours.

Key mechanical vulnerabilities during heatwaves include:

• Engine overheating

• Tire blowouts

• Brake degradation

• Battery failure

• Fuel system complications

• Cooling system breakdowns

These issues are not theoretical. They are recurring hazards that intensify during peak summer months, often leading to roadside emergencies, delayed deliveries, and increased crash risk.

Climate Trends

The study notes that 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 in coming years, amplifying stress on drivers and vehicles alike.

Human Toll: Injuries, Illnesses, and Fatalities

Between June and August in recent years, truck crashes consistently exceeded 19,000 per month, with fatalities surpassing 1,600. Heat‑related injuries are rising across the transportation sector.

A 2025 analysis of 845,014 OSHA‑reported injuries found:

• Injury risk increases once temperatures reach 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 reinforces this trend, showing a 5–6% increase in trucker injury rates when temperatures exceed 90°F.

Cognitive Decline and UV Exposure

Heat doesn’t just affect machinery — it affects the human brain. Several consecutive days above 95°F can impair cognitive performance, slowing reaction time and decision‑making.

UV exposure is another overlooked 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 has real consequences. A documented case of unilateral dermatophilosis in a 69‑year‑old driver showed severe skin damage after decades on the road.

UV Irradiance Hotspots

The study ranks states by average daily UV exposure:

Low‑exposure states include Alaska, Vermont, New Hampshire, Maine, and Massachusetts.

Personal Injury Claims: Heat as a Legal Flashpoint

The study highlights several cases illustrating 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: A System Under Strain

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

Clear, warm days — not storms — produced the highest crash totals.

Crashes by Road Condition

Dry roads dominate crash statistics, contradicting assumptions that icy conditions are the primary threat.

Regional Hotspots

Southern and Midwestern states recorded the highest crash rates per capita in 2025.

Highest Crash Rates (per 100k residents)

Lowest Crash Rates

Fatality rates follow similar regional patterns, with South Dakota, Oklahoma, and Nebraska topping the list.

Conclusion

Sweet James’ study makes one point clear: 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.