HOUSTON — Graham Rahal was racing cars five years before he earned his Ohio driver’s license.

When he turned 16 last year, Rahal, naturally, made it through the driving test with ease. But the instructor was reluctant to give him a perfect score — he wasn’t about to be shown up by the son of former Indianapolis 500 champion Bobby Rahal.

“It was kind of funny,” Graham said. “The guy said, ’Well, I don’t think there’s anything I’d tell you to change, but I can’t put all 4s down, because that will look like we’re making no improvement.’ So he put down all 3s.”

So far, the younger Rahal has aced just about every other test he’s faced behind the wheel.

The 17-year-old is a rookie on the open-wheel Champ Atlantic Series, the developmental circuit for the Champ Car World Series, formerly CART. He made history last weekend, becoming the youngest winner of a race in the 33-year history of the series.

Rahal led all 32 laps last Sunday to win a race in Monterrey, Mexico, by more than 3.5 seconds. It was just his third race in the series. A day earlier, he established a course record while taking his first pole.

Two years ago, he was the youngest driver on the Formula BMW circuit, and finished seventh in the points with five top-five finishes. Last year, he moved to the Star Mazda series, where he again was the youngest driver, and won his first professional race, in Portland, Ore.

Bobby Rahal saw just how much potential his son had last year, when he was testing Infiniti Pro Series cars outside Indianapolis.

“It didn’t take him long to learn,” said the three-time CART champion. “Here he is, driving against guys who are 10 years older, some of them are Formula 1 test drivers, and he’s mixing it up with them. Son or not, I can’t help but be really impressed with that.”

Bobby Rahal said he never pushed racing onto his son. In fact, he would have preferred that Graham had chosen a different career path. But, from the time he could walk, Graham was entranced by his father’s profession — and Bobby never discouraged him.

“When he was 4 or 5, I could take him to a race, he’d hang out with the motor home staff,” Bobby said. “You could take him to dinner with the CEOs of major corporations and instead of him tugging on your sleeve, saying, ’When are we leaving?’ he’d talk to them and when he got tired, he’d put his head in my lap and go to sleep.

“He was always interested in it,” the elder Rahal said. “It’s in his blood, no question about it.”

Graham understands, though, that carrying the Rahal name has its drawbacks. Like other sons of famous athletes, he’ll face the inevitable comparisons to his father.

“Everybody says, ’Are you going to follow in your dad’s footsteps?”’ he said. “Really, I have to make my own.

“There’s always extra pressure on you, but it’s really you who has to perform,” he said. “The best thing, though, is that you know how hard you have to work to do it because you’ve been watching your dad do it for so long. It won’t just be given to me, I know that. You have to work hard for it and I’m pretty aware already that if I don’t work hard enough, I won’t succeed.”

Graham thinks he can blaze his own trail because of how the sport has changed since his father retired from racing in the early 1990s. His ultimate target is Formula One, not either of the open-wheel leagues in the United States.

“The opportunities Dad had may not be the same ones I’ll get. I could get better ones, I could get worse ones,” he said. “The state of racing here in the States is so much different than it was when he was driving. Now, it’s certainly not at the top anymore like it was. We’re trying to build it back up and it takes time.”

Bobby Rahal is ready to support his son in any way he can with one rigid caveat: Graham must excel in the classroom as much as he does on the racetrack.

So far, Graham has held up his end. A junior at New Albany (Ohio) High School, he maintains a 4.0-grade point average, even though he’s missed more than 60 days this year traveling to races. Graham checks in with his teachers via the Internet, makes up tests when he’s home and takes assignments with him on the road.

And it’s no easy class load, either. This semester, he’s taking calculus, German, statistics, history and an English course through the University of Kentucky.

“I honestly don’t have a method to it,” Graham said. “When you go home, you just spend a little bit of extra time making sure it gets done.”

Bobby makes frequent calls to Graham’s school to check up, but said he’s never been forced to discipline his son for missing classwork.

“I don’t know how he does it,” Bobby said. “It’s not like I’m having to drill it into his head. It’s a great challenge for him, but he’s doing a great job with it so far.”

Graham also manages to squeeze in “normal” high-school activities, such as football games and dances. But like his father, his heart already belongs to racing.

“When I go home, I still try to do the things that everybody else does,” he said. “There are things you miss, but it doesn’t matter, in a way,” he said, “because you’re building your career here.”