The ideal car is difficult to define. But here are a few ways to narrow it down:

Check your car type

Car rental companies offer vehicle classes ranging from subcompact to luxury. But these designations are about as meaningful as the star ratings used to grade hotels, which is to say they can be a useful guide, but you shouldn’t give them too much weight. Generally speaking, a subcompact is small and basic; a luxury car is, well, luxurious.

Look at the options

Car rental companies offer a variety of optional amenities, including GPS navigation systems, satellite radio, child safety seats and internet hotspots. Some of these are installed; other items are added at the time of the rental. All are worth careful consideration and some may even be required by law, like the safety seat.

Inspect the vehicle

Then there are the less obvious criteria. How many miles are on the vehicle? What’s the condition of the car? Check the tire tread, to make sure it’s roadworthy. Finally, have a look at the registration on the plate to ensure it’s current and won’t expire before your rental period ends. These can only be determined when you inspect the car personally.

The travelers with the most choice are frequent renters.  Another way to maximize your choice is to be flexible. At a busy time like now, many car rental companies run out of their economy cars. If you’re willing to upgrade to a larger vehicle, you can increase your choices. Savvy renters know that car rental locations run out of the small cars and intentionally reserve them, hoping to score a free upgrade. There’s even a name for it: upgrade roulette. But if you need more room for your trip, that can be a risky move. What if they have your car class on the lot?

When you’re trying to find the perfect car, enlist the help of the agents who are working with you. For example, if you’re renting a car thinking of heading up to the mountains, you’ll definitely want to mention your plans to the agent. There might be a perfect four-wheel drive with an XM Satellite radio in it, just waiting for you.

Think you’ve found the right car? There’s one more thing. Make sure you know how to operate it. Car rental companies are now offering everything from electric vehicles to hybrids to Smart Cars (microcars), and they don’t work the same way the standard gas-operated cars do.

Car rental employees are trained to help you get acquainted with your car. At the very least, check your glove compartment to make sure the manual is there