Q. I've been driving for years but find other motorists seem to be getting more careless, and those are drivers of all ages, at least from my observations. They ignore the rules of the road. --E.H., Chicago

A. A 2008 GMAC Insurance National Drivers Test found that 16.4 percent of drivers on the road -- amounting to about 33 million licensed Americans -- wouldn't pass a written drivers test exam. The survey polled 5,524 licensed Americans from 50 states and the District of Columbia. The survey is designed to gauge driver knowledge by administering 20 questions from state Department of Motor Vehicles exams. Kansas drivers ranked first in the country, with an average test score of 84 percent. New Jersey drivers ranked last, with an average score of 69.9 percent. Illinois ranked No. 32. Drivers more than 35 years old were most likely to pass the test, it was found. Also, while average test scores between the genders were similar, GMAC Insurance spokeswoman Katie Stiffler said the test found that women were more likely to fail the test than men (20 percent vs. 13 percent).

Q. Despite all media warnings, I still see motorists using hand-held cell phones when driving. It's a treat to see some pull to the side of the road to use a cell phone, but I've rarely seen that. --J.S., Joliet

A. I've watched cars on area expressways during rush hours get bonked in the rear, with the driver of the offending vehicle still yawking on a cell phone, as if nothing happened. Nationwide Insurance's annual Driving While Distracted (DWD) study found that a "vast majority" of drivers admit to DWD -- with more than four of five cell phone owners guilty of talking on their phones while driving. The study also found that more than 40 percent of passengers in vehicles have been hit or almost hit by another motorist who was talking on a cell phone while driving. Nearly two-thirds of drivers who own cell phones said colleagues, friends and family members expect them to be (available) via cell phone or other electronic communication devices "at all times."

Q. I'm planning to get a 2002 Acura 3.2 TL that requires premium gas. Would using cheaper regular-grade gas affect performance? A friend owned a 2006 Nissan Maxima that required premium fuel, but his dealer said using regular-grade gas was OK. It said he wouldn't notice the difference between premium and regular-grade. --B.S., Chicago area

A. The 2002 TL requires premium gasoline, mostly because it has a 225-horsepower high-output V-6 with only a 3.2-liter (196-cubic-inch cylinder displacement.) That means the fairly quick car is delivering more than 1 horsepower per cubic inch (once considered sensational) and thus calls for premium fuel. I'm sure the owner's manual recommends premium. The 2006 Maxima has a larger, less-stressed engine that can use regular-grade fuel for routine driving -- although with some performance loss. An engine designed to use regular-grade gas will perform no better with premium fuel, but one designed to give the best performance -- and sometimes fuel economy -- with premium won't be as happy with regular-grade gas. The 2002 Acura mid-size sedan is not a big SUV with a large tank, so filling it with premium shouldn't break the bank. It delivered an EPA-estimated 19 mpg in the city and 29 on highways.

Q. Will the current-generation Toyota RAV4 continue with its spare tire mounted on the cargo door until the next-generation RAV4 is introduced? Will Toyota change to a tailgate for the next-generation model for 2009? --J.S., Elmhurst

A. Toyota introduced the all-new current-generation RAV4 for 2006, so it won't offer a new-generation model as early as next year. Figure on at least a six-year life span for the current model. There's no way Toyota will put a tailgate on the current-generation RAV4, which has a swing-out cargo door hinged on the passenger side, with the attached spare tire.

Q. This question might be from left field, but did Roy Rogers, the all-American singing cowboy who starred in his national television cowboy show, ever endorse a Japanese vehicle? --E.R., Evanston

A. Here's an answer from right field: Rogers, the singing cowboy TV star of the 1950s and 1960s, left his famous horse Trigger in the barn to promote the rugged, two-door Datsun (now Nissan) Patrol SUV in the early 1960s. Nissan exported Patrols to America from 1961 to 1969, selling about 2,600 units during that time.

Q. The "check engine" light came on in my 2001 Nissan with 70,000 miles earlier this year when the engine began to hesitate. My dealer installed a bunch of parts, and the car ran much better. The problem went away. For a while. The "check engine" light comes on again when I drive on the highway, although not in the city. After a few days of "back-to-normal" driving, the light goes off. --D.A., Oak Park

A. The car hasn't been driven an awful lot by today's standards, but it's old enough to have another problem, or problems, appear that trigger the warning light. When it goes on, it registers a code that helps a technician pinpoint the problem. I'd guess the problem is related to the emissions-control system, but in any case the car should be checked again because it might have a small problem that could lead to a major, costly one.

Car question? Send it to Dan Jedlicka, Chicago Sun-Times, 350 N. Orleans, Chicago, IL 60654, or e-mail djedlicka@suntimes.com. Include name and hometown, and be sure to include a self-addressed stamped envelope to ensure a personal reply.