-- Four people are recovering from serious injuries after an amusement park accident outside of London.
The car full of thrill-seekers -- on a ride called “The Smiler” at Alton Towers -- slammed into an empty car stuck on the tracks Tuesday. The force of the collision wedged the cars together.
The accident left 16 riders dangling for more than four-and-a-half hours.
Walter Reiss, a roller coaster safety expert, said modern ride technology deters such accidents from happening.
“This sort of accident should never be able to happen, because there is a very sophisticated computer system that watches the location of all the trains,” Reiss said.
Statistically, amusement park rides are safe -- with the chances of being injured estimated at about one in 24 million.