US RaceTronics has been among the busiest teams in the Atlantic Championship, having tested four different drivers since the conclusion of the 2008 season at Road Atlanta last month.

Last week, at Buttonwillow Raceway, Colombian driver Sebastian Saavedra became the fourth driver to test for the race-winning team, logging more than 225 miles in a one-day test.

"Sebastian was very quick right out of the box," USRT owner Shane Seneviratne said of the FBMW and German F3 graduate, "His lap times were very competitive and, by the third session, he seemed to hit his stride.

"Once he established a good baseline, we worked on getting him faster and to get the car more to his liking. With some tyre strategy, he became faster, and I was real pleased with his performance and his feedback."

Having stepped up from a successful FBMW career in the US, 18-year old Saavedra raced in this year's German ATS F3 Cup, taking second overall and top rookie honours.

"I am real happy with how the test went," the Colombian said of his Atlantic debut, "We were fast right from the start and the team made my first time in an Atlantic car a great experience.

"I got to become more comfortable with the car and it showed with my lap times improving. Many thanks to USRT and Shane for their hard work over the last couple of days. Hopefully, a good opportunity can result from this test."

Sergio Pena, Juan Camilo Acosta and Juan Carlos Sistos have all also tested for the USRT team this autumn.