Basic Trope: A car is rigged to explode when started.
Straight: Bob walks to his car, puts his key in the ignition... *BOOM*
Alice wishes Bob a nice trip, and laughs an Evil Laugh. A long shot shows him approaching his car. The camera focuses on the key in the ignition while Ominous Music plays. The car explodes with an Earth-Shattering Kaboom.
Every vehicle in the car park is rigged to blow when the target starts his car.
Justified: The enemy is an ex-IRA explosives expert now working as a car mechanic, and wants to make sure no-one ever identifies the body.
Bob rigs a remote-detonated bomb to go off when he starts his own car, perhaps to destroy his office if he has to make a quick getaway.
alternatively: Bob's car is rigged to explode when he stops.
Subverted: Bob had found the bomb before time and moved it to his enemy's vehicle. They watch him drive off, and jump in their own car...
Double Subverted: ...just to retrieve the remote control for the backup bomb they put in his glovebox.
Parodied: Bob gets on a pushbike, kicks up the stand, and the bike explodes.
Zig Zagged: ???
Averted: Someone waits near the car until Bob shows up, and Just Shoots Him.
Lampshaded: "If only Bob hadn't turned that ignition key. Then he'd still be alive."
Invoked: A mob boss doesn't want a snitch going anywhere, so he sends some dodgy-looking mechanics to tinker underneath the guy's car when he knows he'll see them.
Defied: "Whew, when Big Tony gave me the keys to a new car I kinda thought it would be a trap..."
Discussed: "50 quid says the car explodes when I turn the ignition"
Conversed: "So the Mafia supergrass is letting his girlfriend bring the car around for him. Sheee's dead."