Q: In the 1980s the federal government required cars to have bumpers that can withstand minor crashes of 5 mph with no damage. Is that still a requirement? Some current models (e.g., Lexus, Toyota) have grilles that have no apparent bumpers.

A: You might not always see them, but all cars have bumpers. The Lexus bumper you refer to hides behind a fascia. Cars that appear to have actual bumpers have bumper covers that hide the real bumpers. At 5 mph, the bumper cover will get damaged, but the hidden bumper will still do its job.

Spare the transmission

Q: When visiting our daughter, I park in her driveway, which has quite a slope. When leaving, it seems that the shifting from park to reverse is extremely hard on the transmission, producing a loud ping and jerk. Should I consider parking in the street, which is more level but a distance from the house? How does this impact the transmission?

A: When you park on an incline, the car moves just enough to put pressure on the parking pawl in the transmission. When you shift out of park, you must overcome that pressure. If you use your parking brake, you won't have this issue. Try this: With your foot on the brake pedal, set the parking brake and then shift into park. When you are ready to leave, repeat these steps in reverse (no pun intended) order.

Won't stop running

Q: I own a 1969 Buick with a 430 CID engine with 130,000 miles on it. When I go to shut it off, the engine keeps running. The only way I can get the engine to stop is by disconnecting the positive battery cable. When I hook the positive cable back up with the key out of the ignition, I get sparks, like something is still on. Any suggestions?

A: What you're describing is called engine run-on. It was rather common on cars with external voltage regulators. Even with the key off, a small amount of current coming directly from the battery can energize the ignition system. Chrysler vehicles of this vintage had ballast resisters mounted on the firewall to absorb that errant current. Check that.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.