Dear Tom and Ray:

To use the emergency brake or not -- that is the question! We bought a Mazda3 with a manual transmission for our son, and the question is whether he should engage the emergency brake when he parks his car. He leaves the car in gear but does not engage the emergency brake when he parks.

He knows that if he were to park on a hill, he could engage the emergency brake for additional security (we've also talked to him about turning his wheels depending on if he is facing downhill or uphill). The question is: Should he just simply engage the emergency brake all the time -- make it a habit? His father thinks one way, his mother thinks the other. What do you all say regarding the best practice to teach our son?

-- Kimi

RAY: He should make using the parking brake a regular habit, Kimi.

TOM: With an automatic transmission, using the parking brake is not as crucial, because putting an automatic transmission in park actually locks at least two of the car's drive wheels. But if you're driving a car with a manual transmission, there's not much between staying parked and rolling down Pike's Peak.

RAY: Putting the manual transmission in gear doesn't "lock" anything; it makes the car harder to move, because you have to overcome the resistance of the engine, but it's hardly impossible to move a manual-transmission car that's in gear. And if the clutch is worn out, or your engine compression is low, it's that much easier for the car to roll.

TOM: It also can be knocked out of gear in a way an automatic transmission can't. If you're putting packages in the car, or if the dog jumps in first, it's possible to knock the shifter out of gear and send the car a-rollin'.

RAY: So, for those reasons, we recommend that everyone with a manual transmission make a habit of applying the parking brake every time they park the car.

TOM: The reason you want to use it every time is twofold: One reason is to simply get in the habit so you remember to apply it -- and, just as importantly, remember to release it whenever you drive away.

RAY: Second, when a parking brake isn't used regularly -- particularly in climates where rust is an issue -- the cables, which run under the car -- can corrode and get stuck in place. Then one of two things happens: Either you can't use the brake when you need to, or you snap the cables trying.

TOM: So tell your son it's just another one of those good habits to get into. Floss your teeth, call your mother once a week and use your parking brake.