You can probably thank director Renny Harlin’s “Die Hard 2” for the influx of vehicle-based “‘Die Hard” riffs that flooded the market in the ’90s, including those set on planes (“Air Force One”), trains (“Under Siege”), and automobiles (“Speed”). (John Hughes, we thank you for your service.) Director Jan de Bont’s “Speed,” in particular, might just represent the peak of this formula. The 30-year-old film saw the first-time helmer, who had previously honed his visual sensibilities as a cinematographer on the likes of “Cujo,” “Black Rain,” and “The Hunt for Red October,” delivering a tight-as-hell, crowd-pleasing thrill ride.

It’s also difficult to say which generates more sparks in the movie: the bus racing across Los Angeles at 50 miles per hour to avoid triggering the bomb latched onto its undercarriage, or the flirty, flustered exchanges between LAPD SWAT officer Jack Traven (Keanu Reeves) and Annie Porter (Sandra Bullock), the hapless passenger who ends up having to take the steering wheel after Jack boards the vehicle and informs everyone of their dire situation.

What’s interesting about Jack is that he’s not the typical blustering ’90s action movie lead. There’s no swagger in his footstep, nor is he a devoted family man moving heaven and earth to rescue his loved ones (or a loose cannon who would sooner crawl over glass and leap off a building to save his wife than go to marriage counseling). Instead, he’s as straight-laced as they come, a good guy who’s there to do his job and mind his p’s and q’s while he’s doing it. (Except when he uncovers some shocking information about the bomb and understandably looses his cool for a moment, letting out an impromptu “F*** me!”)

As it turns out, much of the credit for that belongs to Reeves himself.

Keanu Reeves did his research for Speed

The “Speed” script was, incredibly enough, primarily the handiwork of two eventual titans of television in Graham Yost (creator of “Justified” and “Silo” and a key creative on “The Pacific” and “Band of Brothers”) and disgraced “Buffy the Vampire Slayer” mastermind Joss Whedon. Both humble scribes hungry for their big breaks at the time, Yost wound up receiving sole credit for de Bont’s 1994 blockbuster despite Whedon having reportedly contributed the vast majority of dialogue as a script doctor (though, shockingly, not the legendary “Pop quiz, hot shot!” line, much as that reads like a quintessential Whedonesque quip). However, it was Reeves who really nailed down how to portray Jack.

In fact, Reeves initially had ambitions of subverting the John McClane archetype even further. “He also said, ‘I don’t want to pull my gun,'” Whedon recalled. “And I was like, ‘I don’t want you to either, but you kind of have to. […] [The studio is] not going to let you not pull your gun.'” Bless Keanu for trying, anyway.