Q: Your column about vent windows reminded me of my '93 or '94 Chevy Traverse. One mild day I rolled down the four side windows. Upon leaving town and accelerating to 55 mph, I thought the car was coming apart since it was vibrating like crazy. It happened again with my Hyundai. I think aerodynamic design is causing this.

K.G., Grant Park, Ill.

A: The phenomenon is called wind buffeting. And you are right, the smooth styling does not deflect the air as some old-fashioned cars used to do. But even in the pre-aero days, buffeting often occurred when the rear windows were opened. Enjoy the fresh air around town and then switch to A/C on the highway. It even saves gas.

Q: I discovered the bad side of vent windows after a thief broke into my parked car through the curbside passenger vent window and stole my stereo system. The police explained that a thief could pry open the vent window with a beer can opener, then reach inside to open the door. My next car, and all subsequent cars, haven't had a vent window. Good riddance.

J.D., Chicago

A: That was a sinful use of a trusty church key. We seem to recall vent windows having a latch that required the push of a button before turning to open the window.

Q: In response to J.R. from Allentown, Pa., who narrowly escaped a carjacking while at the pump, here's my advice: When filling your vehicle at the pump, turn the engine off, remove your keys, and then start filling. Whether it is a stick shift or an automatic, a carjacker can't hop into your vehicle and drive off if you haven't already INVITED him to do so!

D.B., Elk Grove Village, Ill.

A: Good idea. But it probably won't do much good if the bad guy has a weapon.

Q: A few years ago I visited an auto window tinting company and was told that applying any degree of tint to a windshield was unlawful. My neighbor, a police officer, verified the law. Of late I've seen car after car with windshields tinted — some so dark the driver cannot be seen. I've also read many times that a license plate frame cannot cover the name of the issuing state. However, frames of every width and design are readily sold and only the numbers/letters are clearly visible, with no other hint as to its state of issue.

P.K., Davie, Fla.

A: Only a small portion of the windshield may be tinted, no lower than the AS1 line. Look for it in the upper corner on the passenger side. In Florida, the front side windows must allow at least 28 percent of the light to pass. Rear side windows and the rear window, 15 percent. According to Florida law, no part of the license plate may be obscured from view. This includes not only the name of the state, but the slogan "Sunshine State" or any vanity plate information. Other states have similar regulations.

Bob Weber is a writer, mechanic and Master Auto Technician.