• Keep cool. Excessive heat can dehydrate you, causing erratic blood sugar levels. It can also damage insulin and diabetic supplies. If it's hot, use your air conditioner. You'll actually do better on gas mileage when highway driving if you leave the windows up and the AC on, anyway.
• Stay out of direct sun. Use a windshield screen to keep the heat down in the car when you're parked, and crack the windows to encourage ventilation. Depending on the material and color of your car interior, your upholestry, steering wheel, stick shift, and other controls could heat up to dangerous, skin burning levels. Carry a spare towel or blanket in the trunk to cover hot seats, and never keep blood glucose meters and supplies, insulin, or medication in a hot car.
• Lather up. Burns are especially dangerous to people with diabetes. Even when you're driving in the car, the sun's rays can reach you through windows and sunroofs. Before you get in the car, put on sunscreen with a sun protection factor (SPF) of at least 15. If you're out with the top down or the roof open, wear a wide-brimmed hat to protect your head.
• Snack safely. Always have adequate non-perishable snacks on hand, including fast-acting carbohydrates, to treat any blood sugar lows in case traffic or circumstances delay a meal. Foods that are perishable should be kept in an insulated cooler; replace the ice or ice packs regularly.

More travel tips from dLife.