Here are some tips, compiled by 21st Century Insurance and the National Weather Service, on how to winterize a vehicle. You might want to pass this advice along to your drivers as a friendly, seasonal reminder.

1. Flush the cooling system and replace the coolant. The ideal mixture of antifreeze (coolant) and water inside your vehicle's radiator is 50/50. If the mixture deviates from this norm, then hot- and cold-weather performance can suffer.

2. Check your windshield wiper blades. If your car's blades are worn or older than one year, make sure to replace them.

3. Replace your windshield washer fluid. Use cold-weather fluid that will not freeze at the coldest winter temperature. Visibility can easily be compromised by salt build-up on the windshield.

4. Check your battery. Very cold temperatures can reduce a vehicle's battery power by up to 50%. Have your battery serviced and load-tested to check its ability to hold a charge. If the battery is more than four and-a-half years old, you may need to replace it.

5. Check tire pressure. As the temperature drops, your tires will likely lose pressure. While you’re at it, make sure there is air in the spare tire and that all the proper tire-changing equipment is in the vehicle.

6. Make sure your tires have plenty of tread.
 Worn tires on a slick road are extremely dangerous. If you are not sure about the condition of your tires, consult your mechanic.

7. Keep the gas tank as full as possible. A full tank of gas not only helps in the case of bad weather, but it also helps prevent moisture from freezing in the gas lines.

8. Get a tune up.
 Check your owner's manual for the recommended intervals.

9. Pack a safety kit. An emergency situation on the road can arise at any time, so it helps to be prepared. Here are some items to carry in your trunk:

  • A flashlight, flares and a first-aid kit
  • Jumper cables, a tool kit and tire chains
  • A blanket, warm clothes, hat and gloves
  • Paper towels
  • A bag of salt or kitty litter for added traction when a tire is stuck
  • A snow brush, ice scraper and snow shovel
  • Extra windshield washer fluid
  • Extra food and bottled water.

Here are some more tips from Nationwide Insurance: