In the biggest experiment with interactivity, and additional content created expressly for DVD, by a major studio, New Line Home Entertainment is putting together an interactive “Thrill Ride” edition of “Final Destination 3.”

Release, due in stores July 25, will give viewers repeated opportunities to make life-or-death choices for its characters.

Other studios have offered discs with alternate endings and interactive features, but never at this level.

New Line’s “Thrill Ride” edition marks the latest attempt by studios to boost DVD sales through enriched content. Studios have begun pumping out extended editions of hit movies — New Line’s “Wedding Crashers Uncorked” and U’s unrated version of “The Forty Year Old Virgin” being two notable examples — under the belief it will stimulate sales among viewers who have already seen the movie.

Eager to explore interactivity on a high-profile project — smaller distribs have periodically tried it on direct-to-video pics without making much of a splash — the homevid unit quickly identified the next “Final Destination” installment as a likely candidate.

“For this to really work, we thought, we’ve got to engage A-level filmmakers that are already working for us,” New Line homevid senior VP of content Mike Mulvihill said.

Once helmer-scribe Jim Wong wrote 25 new script pages, it was just a matter of getting the requisite budget approvals for the extra costs, which New Line pegs between $700,000 and $1 million. Pic’s budget was just under $30 million.

The “Thrill Ride” edition gives viewers seven choices at 10-minute intervals. Among the choices that pop up onscreen: “Should Wendy take another look?” and “Map” or “No Map.” Viewers can also opt to see the theatrical version of the movie.

“Honestly, trying to keep it all straight down to the props was really mind-boggling,” said producer Craig Perry.

Also a challenge: keeping the interactive version a secret during the pic’s theatrical run. “New Line homevideo basically made us sign our lives away,” Perry said, noting the film was shot a year ago and underwent significant post-production without word getting out.

Although videogames have been adapted to movies with mixed success, the creators of “Final Destination 3: Thrill Ride” treat it as a movie, albeit with interactive qualities.

“We weren’t trying to make this anything other than a movie experience,” Mulvihill said.

He says New Line plans to do another interactive project, but is waiting to see how consumers take to this version, which comes in a two-disc set, along with director commentary and a behind-the-scenes docu.