Motormouth: Green, amber and read taillights: Good idea?

McClatchy-Tribune Information Services

September 2, 2019

Q: In a recent column, a reader asked about having an amber light showing when the driver had lifted his or her foot from the accelerator. Twenty-five or 30 years ago I saw just such a device while driving into Chicago on the Eisenhower Expressway. The car in front of me had something that looked like a traffic light mounted in the rear window. When the driver was on the gas the green light was on, when he lifted off the accelerator the yellow light was on, when he stepped on the brake the red light was on.

I followed him for quite a while and thought this was a pretty clever and useful device. Iíve never seen another one and have no idea whether it is still sold, but it was definitely helpful to me as I followed him on a highway known for situations where traffic speed can change suddenly.

ó B.J., Mendota, Ill.

A: I have been to many automotive parts and accessory expos and have never seen anything like the item you describe. I would not be surprised if some clever reader spots this column and starts making them. But nowadays, it would have to use LEDs for lights, an accelerometer to detect slowing and maybe even Bluetooth for who-knows-why or it may not move off the shelf. Would it be legal? Letís just say, nobody seems to get a ticket for the obnoxious lights they display.

Q: Many cars already have a warning that they are slowing down. Some hybrids and EVs light up the brake lights when you take your foot off the accelerator and engage regenerative braking. My Prius doesnít, but its regen is relatively mild. Still itís good enough that brakes are rarely used, and ours lasted over 90K before ever needing any brake work.

Several years ago I test drove a BMW I3, and itís very aggressive regen would turn on the brake lights. It would actually bring the vehicle to a complete stop. Our year-old Tesla 3 is not quite as aggressive as the I3, but still activates the brake lights when you back off the accelerator. The console display shows you the red lights turning on when they are activated. It wonít quite stop the car, but itís enough braking that you have to be careful on snowy, icy or slick roads. And brakes are expected to last even longer than on the Prius. Itís almost one foot driving.

ó B.K., Chicago

A: Good point and one that totally slipped my mind. Regenerative braking slows the vehicle much more than traditional coasting as the traction motors morph into generators to recharge the batteries. As such, some carmakers switch on the brake lights to alert following drivers. Although some people believe that regen braking improves fuel economy, it does not. But it does help to keep the propulsion batteries charged.

Q: Is the E-85 gas sold in Speedway gas stations safe to use in cars, specifically my 2016 RAV4?

ó B.O., Chicago

A: When I see that low, low price for fuel, the temptation is to give E85 a try. But unless your vehicle is designed to run on E85 (85% alcohol and 15% gasoline) donít do it. Only two 2016 Toyotas were flex fuel compatible, the Tundra pickup and the Sequoia SUV. When in doubt, check your ownerís manual.

óóó

ABOUT THE WRITER

Bob Weber is a writer and mechanic who became an ASE-certified Master Automobile Technician in 1976. He maintains this status by seeking certification every five years. Weberís work appears in professional trade magazines and other consumer publications. His writing also appears in automotive trade publications, Consumer Guide and Consumers Digest.

Send questions along with name and town to Motormouth, Rides, Chicago Tribune, 160 N. Stetson Ave., Fourth Floor, Chicago, IL 60601 or motormouth.tribune@gmail.com.