Patrons wait to board a driverless shuttle bus on a street in Las Vegas. Picture: Regina Garcia Cano / AP

Las Vegas, Nevada - Less than two hours after the launch of America's first self-driving public shuttle service, it was involved in a collision with an 18-wheeler truck. But before you jump to the obvious conclusion, Las Vegas police have charged the (human) driver of the truck!

Officials had hosted an unveiling ceremony to promote what they described as the United States' first self-driving shuttle pilot project geared toward the public, as dozens of people lined up in downtown Las Vegas to get a free ride. 

The oval-shaped electric vehicle, developed by the French company Navya, can transport up to 12 passengers, and has an attendant and computer monitor on board, but no steering wheel and no brake pedal. It uses GPS, electronic kerb sensors and other technology to navigate the traffic.

City spokesman Jace Radke said the shuttle stopped when it sensed the truck was approaching, but the truck didn't stop.

Las Vegas police Officer Aden Ocampo-Gomez said the truck reversed until one of its tyres hit the front of the shuttle. Nobody was hurt, he said, but the crash blocked traffic near the Fremont Street entertainment district.

The driver of the truck was charged with illegal reversing.

The shuttle didn't have any dents, said Radke, and it completed two more loops after the crash.