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This summer’s extreme heat waves are a reminder that a car can quickly become dangerous for both drivers and passengers. Even when the outside temperature is only 25°C, the interior of a vehicle parked in direct sunlight can reach 45°C within 30 minutes and 60°C within an hour. During the current heatwave, temperatures inside a parked car can climb to 60–70°C in just 15–30 minutes.
Surfaces such as the steering wheel and dashboard may heat up to around 70°C, while metal components can exceed 80°C, creating a serious risk of burns.
The greatest danger is for children and pets. Temperatures of 40–45°C inside a vehicle are already critical, and young children are especially vulnerable because their bodies cannot regulate heat as effectively as adults. Safety experts stress that children or animals should never be left in a car parked in the sun, even for a very short time.
Heat also affects driving performance. Research by Germany’s GTÜ and ADAC shows that as the cabin temperature rises from 25°C to 35°C, the risk of a traffic accident increases by about 20%. Drivers in such conditions may experience faster heart rate, reduced concentration and slower reaction times. According to the experts, driving in extreme heat can impair performance in a way comparable to having about 0.5‰ alcohol in the blood.
Dark-colored cars absorb much more solar energy than light-colored ones. ADAC found that the surface of a black car can reach around 65°C, compared with about 44°C for a white car parked under the same conditions. The difference inside the cabin is much smaller, but dark vehicles release more heat into the surrounding environment and contribute to the urban heat-island effect.
Many everyday items become hazardous in a hot vehicle. Experts warn against leaving:
- medications, especially insulin and antibiotics;
- smartphones, laptops, tablets and power banks;
- aerosol sprays;
- carbonated drinks;
- flammable liquids and cleaning products;
- perishable food;
- plastic or wax items;
- expensive glasses or jewelry.
Lithium batteries can overheat and catch fire, while pressurized containers may explode. Even clear plastic bottles can act like magnifying lenses and ignite paper or fabric under certain conditions.
To reduce heat buildup, drivers are advised to park in the shade whenever possible, use a windshield sunshade or a reflective cover, and keep sensitive items out of direct sunlight. Before starting a trip, it is best to open the doors and windows for a few minutes to let the hot air escape, and only then switch on the air conditioner.
ADAC recommends initially driving a short distance with the windows open and the ventilation running at maximum power, then closing the windows and turning on the air conditioning. The most comfortable cabin temperature is around 22–24°C, and the cold airflow should not be directed straight at the face or body.
Drivers should also check tire pressure when the tires are cold, since pressure rises significantly in hot weather. Proper tire pressure improves vehicle stability and reduces the risk of accidents during summer travel.
