About the title
A terrorist plants a remote-detonated bomb on a city bus that will explode if the bus's speed drops below 50 mph (80 km/h). After the bus pulls onto the highway and picks up speed, the device is activated, and the bus itself turns into a "speed bomb" full of hostages, unable to stop. A special agent, together with a chance passenger who happens to be behind the wheel, searches for a way to save everyone's lives.