How Summer Heat Impacts Driver Safety – And How to Adapt

As Australia moves deeper into the summer months, fleet operators face a predictable yet often underestimated challenge: extreme heat. While many focus on vehicle maintenance and hydration, few recognise the full scope of risks that rising temperatures bring to driver performance and road safety.

Data from AlwayCare's Australian fleet network shows a 22% increase in safety incidents during heatwave conditions—particularly between 2 PM and 5 PM, when fatigue and glare combine to create high-risk driving windows.

David Xiao, AlwayCare's Head of Safety Research, explains how heat affects driver behaviour and what fleets can do to protect their teams during the hottest months of the year.

High temperatures significantly increase mental and physical fatigue. Research indicates that cabin temperatures above 27°C can reduce alertness by up to 30%, slowing reaction times and impairing decision-making.

“Drivers may not even realise they're overheating until their concentration starts to drift,” says Chen. “By the time they feel thirsty or tired, their ability to react safely has already declined.”

Longer days and stronger sun angles create intense glare—especially during morning and afternoon commutes. This can temporarily blind drivers, obscure pedestrians, and make it harder to read road signs or spot hazards.

Heat accelerates wear on tyres, brakes, and cooling systems. Breakdowns become more likely, increasing the risk of roadside incidents—particularly on highways or in remote areas where help may be hours away.

Hot nights mean poorer sleep quality, leading to cumulative fatigue over multiple days. A driver who hasn't slept well is significantly more likely to make errors, even if they don't feel overtired.

Based on analysis of over 50,000 hours of summer driving data, AlwayCare recommends these evidence-based approaches to reduce heat-related risks:

Encourage drivers to drink water before they feel thirsty. Dehydration can set in quickly, and once it does, cognitive performance drops rapidly.

• Provide insulated water bottles to keep drinks cool

• Schedule reminders for drivers to hydrate every hour

• Recognise that air conditioning can mask dehydration symptoms

Where possible, avoid having drivers on the road during the hottest parts of the day (12 PM–4 PM). If that's not feasible:

• Reduce speed expectations by 5–10 km/h to account for longer stopping distances

• Plan routes that offer more shaded sections or shorter exposure to direct sun

• Build in extra break time for drivers to cool down and rehydrate

“Technology can't change the weather, but it can help drivers and managers make smarter decisions in the moment,” Xiao notes.

Prepare Now – Not When the Thermometer Soars

• Servicing air conditioning systems before the heat peaks

• Trialling adjusted shift patterns to avoid peak UV hours

With climate models predicting longer and more intense Australian summers, these adaptations aren't just seasonal tips—they're becoming