Ideally, to accurately compare one car with another, you should test-drive all of your candidate vehicles on the same day, preferably on the same or similar roads. A multibrand "auto mall" is one place to do that, even if you don't end up buying from there. You will be able to drive each car along an identical test route and compare all of them in the same afternoon.

Before your test-drive, be sure to check these items off your to-do list:

Grade Your Current Vehicle

Make a list of the things you like and dislike about it: performance, comfort, features, fuel economy, controls, and any idiosyncrasies. Does the seat give you a backache on long trips? Is there too little storage space? Are there cup holders that don't hold drinks securely? Which tech features does your car lack? Put down all of your gripes—large and small—so that you don't overlook those things in the new car.

Plan Your Own Route

If a salesperson goes along with you on your test drive, he or she will probably suggest a quick, well-used route that's "friendly" to the vehicle and doesn't stress the engine or suspension too much. But this won't give you a complete picture.

Try to plot out a route of your own in advance, one that lets you experience various traffic situations and different types of roads. Include a stretch of broken or washboard pavement and speed bumps in the loop. Winding country roads and/or high-speed freeways, if you normally drive on them, should also be part of your route.

It would be best if you were able to spend at least a half-hour test-driving each vehicle. If you can, go on a route that you are familiar with so that you'll be able to spend more time focusing on the car instead of an unfamiliar road.

Schedule Appointments

When you call the dealerships, confirm that the vehicle or vehicles you want to test-drive are in stock and equipped the way you want. If you're contemplating a car with the base engine, it doesn't make sense to test-drive a fully loaded demo with the uplevel powertrain. Beyond the engine differences, there may be variations in suspension, wheels/tires, and even sound deadening. Schedule your appointments to drive candidate cars back-to-back.

Be Prepared

Before the big day arrives, assemble the items you should take with you. These include the following:

  • Your car-insurance verification.
  • A way to record your thoughts and observations about each car.
  • Your list of likes and gripes about your current vehicle.
  • The exact vehicle configuration—including trim level, features, and options—for the vehicles you want to test-drive.
  • Any media, including your cell phone with music, podcasts, and apps, to try the audio system.
  • Child seats to be sure you can secure them easily in each vehicle. If possible, have your partner or spouse come along to take notes, ask questions, and, if you'll share the car, test-drive it as well.