Across the nation, temperatures have been soaring this spring and summer. June went down in the history books as the hottest in 140 years, according to the National Oceanic and Atmospheric Administration's (NOAA) National Centers for Environmental Information.

Extreme heat can wreak havoc on vehicles and create dangerous situations for commercial drivers. High temperatures can lead to engines overheating, breakdowns, and tire blowouts. Make sure to remind your drivers about critical steps they can take to protect their vehicles and themselves during debilitating heat waves.

Experts offer the following nine tips:

1. Check the Battery

Heat evaporates battery fluid more quickly, so check your vehicle’s battery during the summer to ensure it is not corroded.

2. Watch for Warning Lights

The alternator replenishes the battery but when subjected to heat and constant air conditioning it gets pushed to the max. Make sure to watch the battery warning light on the dashboard and if it does not disappear, make sure to get your battery tested.

3. Keep Your Cooling System in Shape

Engines work overtime when the temperatures rise. Periodically flush and replace coolant and check your oil regularly.

4. Properly Inflate Tires

During a summer hot spell, asphalt roads can get as hot as 140 degrees. When underinflated tires meet hot roads it's a lethal combination — one that raises the risk of blowouts. In the summer months, check tire pressure frequently and make sure to fill them to your vehicle manual's specifications.

5. Park in the Shade

On an 85 degree-day, the interior of a parked vehicle can reach 100 degrees — in just 10 minutes! To keep your vehicle's interior as cool as possible, park in the shade or use sunshades to cover your front window. Leaving your windows open just a tiny bit is also a smart move.

6. Turn on the AC

Once inside a hot vehicle, immediately crank up the air conditioning and adjust the vents to have the air come through the lower openings.

7. Stay Hydrated

Drivers should drink plenty of water while on duty in the summer. Even if you're not feeling thirsty, make sure to keep drinking water.

8. Stop for Breaks

Heat can make drivers drowsy. Make it a practice this summer to pull over and take a break or stretch your legs every few hours. 

9. Keep a Survival Kit

In case your vehicle does breakdown on a very hot day, it's smart to have a summer survival kit on board. It should include a fully charged cell phone, sunscreen, a first aid kit, healthy snacks, and extra water.