Q: Some months ago you wrote about a car manufacturer that offers blind-spot detection technology. I recall being interested, but didn't want to buy a car then. Now that it's been around awhile, are larger numbers of cars offering this option? And if so, which are they?

A: You can get this technology, which warns if there's another vehicle in the way when you indicate you're going to move into a different lane, on some models from Cadillac, Buick, Audi, Mercedes, Volvo and Mazda.

Q: In my old car, I knew that when the low-fuel light popped on, I could still go about 45 miles before completely running out of gas. But I learned with a rental car a couple of weeks ago that there's evidently no standard that manufacturers abide by, because 30 miles after the light came on, I was completely and totally out of gas. I just bought a new car and I want to know what to expect, but there's nothing in the manual to tip me off.

A: You're right. Manuals aren't going to tip you off about precisely how far you can drive on fumes. Car manufacturers prefer that you not push this to the extreme, because it's not especially good for a vehicle and also because they might promise a certain number of miles that you don't quite achieve due to any number of variables that can affect a car's fuel economy.

You're also correct in your assumption that there is no "standard" that extends across the industry. You might get 20 miles after the light comes on or you might get 60, depending on the make and model.

But there is a way to determine how many miles you can eke out during those post-warning-light moments. Next time you're running near empty, cruise around town until the light comes on and then immediately dash into gas station for a fill up.

Watch the pump to see how many gallons went in, consult your manual to see how many gallons your tank holds, subtract the former from the latter and you'll discover how many gallons remained in the tank when the light popped on. Maybe 1.5 gallons gallons remained in your tank. If your car normally gets 20 miles per gallon, you'll know to expect about 30 miles when the light appears.

But - and it's a giant "but" - you could very well get considerably fewer miles in real-life circumstances, such as climbing hills, traveling at speeds of 50 mph or more or even carrying five passengers, luggage or a canoe on the top. So use this experiment only as a guide, and reduce your expectations by at least 10 or 20 percent.

My recent answer to a woman who wondered how to convince her do-it-himself, oil-changing brother-in-law to clean up the oil puddles he leaves on his driveway after he changes his oil prompted a flurry of e-mails. Several said I should have advised the woman to call the authorities and have him hauled off to prison.

Not a bad idea. But I'm not sure how many representatives of officialdom, with all the recent budget cutbacks, would feel they had the resources to pursue prosecuting someone whose sloppiness resulted in a washcloth-size oil slick in his driveway. Maybe it's worth testing.

A few others offered some anecdotes about how dangerous the oil-and-water combo is - on driveways, for sure (one woman detailed a rather gruesome slip and fall in her own driveway after a gentle spring rain), but especially on highways.

One e-mailer recalled a time that he was driving very slowly in a light rain, maneuvering into a parking place, and when he tapped the brakes he slid sideways into the curb, bending a wheel.

As one California man wrote, "Stopping on ice is easy compared to trying to stop on wet, oily surfaces."