Indianapolis ? In a bid to improve lagging ratings for the Indianapolis 500, ABC is trying to get the track to change one of its most revered traditions — the start time.

As usual, the green flag is scheduled to wave Sunday at 11 a.m. local (Central) time. But ABC, which announced an extension of its TV deal with the Indy Racing League through 2009, would like the race to begin later in the day.

The IRL is considering the suggestion seriously.

“We have a formula for addressing it,” said Ken Ungar, senior vice president of business affairs for the IRL. “There’s nothing definite. But it’s beyond just an idea.”

Another television-friendly idea was met with less enthusiasm from Indy officials: running the 500 at night. That would require a massive lighting project that track officials aren’t yet ready to tackle or fund.

“Sure, we would love the opportunity to do the Indy 500 in prime time,” said Loren Matthews, senior vice president of programming for ABC Sports. “But they say it’s not realistic at this point in time. We understand that. We’re trying to balance tradition with reality.”

The ratings for last year’s race were less than half of what they were in 1995, the final year before a split in open-wheel racing led to the formation of the IRL and a boycott by Championship Auto Racing Teams (CART), which had most of the top drivers and teams.

ABC believes it could stem the ratings slide if the race started in the afternoon, luring more viewers, especially from the Mountain and Pacific time zones. The scheduled start has been 11 a.m. since 1963.

“It’s no secret that home usage of TVs grows the later you get in the day,” Matthews said.

The ’95 race drew a 9.4 rating and 29 share. The numbers dipped significantly the following year — when CART teams staged a protest race in Michigan — and have largely continued to fall, earning a 4.6 rating and 14 share last year.

One clear drawback to starting the race in the afternoon: NASCAR drivers such as Robby Gordon and Tony Stewart no longer would have time to attempt “The Double,” running both the Indy 500 and the Coca-Cola 600 at Lowe’s Motor Speedway in North Carolina on Sunday night.

Largely owing to its tradition as an American sporting icon, Indy still draws by far the largest ratings of any open-wheel race. Then again, viewership for the IRL and rival Champ Car series (successor to now-bankrupt CART) pales in comparison to the NASCAR Nextel Cup series.

Still, ABC and cable partner ESPN are sticking with open-wheel racing through 2009, highlighted by coverage of the 500.