Some contrived implausibilities are acceptable in any adventure film. Now, admittedly, in Speed (more an "action" than adventure film) the suspension of disbelief is impossible to maintain completely given the rules of the plot (e.g. "Don't go under 50 mph.").
However, if you want to see the WORST of action/adventure contrivance, may I direct your attention to the following films:
Allan Quatermain and the Lost City of Gold - Lesson learned: You can hold an axe in a lightning storm and get hit with electricity over and over again without dying...Oh, and a cotton shirt stops spears.
Superman IV - Lesson Learned: Provided you have the ability to fly, you can leave a normal human in orbit around the Earth without fear of them suffocating, imploding, freezing, and/or drifiting into outer space.
Goldeneye - Lesson Learned: You can dive off a cliff after a falling Cessna, catch up with it, pull yourself inside the plane, work your way to the cockpit, and pull the plane out of a vertical dive at terminal velocity with your bare hands without ripping the wings off the plane.
Charlie's Angels 2 - Lesson Learned: You can dive off a cliff after a falling Apache chopper, catch up with it, pull yourself inside, work your way to the cockpit, start the chopper in mid-dive, and pull the whirlybird out of a vertical dive at terminal velocity with your bare hands while other skydivers hang onto various bits of the aircraft without falling off.
UGH