The driver of the truck was issued a traffic citation, Las Vegas officials said in an online post about what they called a minor collision.
"The shuttle did what it was supposed to do, in that its sensors registered the truck and the shuttle stopped to avoid the accident," the city posted on the online platform Tumblr.
"Unfortunately, the delivery truck did not stop and grazed the front fender of the shuttle."
The Arma shuttle made by French firm Navya was taken out of service on what was the opening day of a year-long test program of autonomous service in Vegas.
Arma shuttles operating in a collaboration with the Keolis transport group are providing free rides along a route in downtown Las Vegas, away from the casino-lined main strip.
Operators are on board the shuttles to act more as hosts than back-up drivers, according to a company spokesperson.
The pilot program is being sponsored by the American Automobile Association and was billed as the nation's first self-driving shuttle service for the public.
"In addition to studying how the shuttle interacts in a live traffic environment in downtown Las Vegas, AAA will survey riders on their experience in order to understand why a large percentage of consumers remain wary of driverless technology and whether a personal experience changes their perception," the city said.
Navya on Tuesday unveiled an electric-powered, self-driving Autonom Cab designed to provide local rides for people in urban centers.
The Autonom Cab has no steering wheel or foot pedals, and is capable of carrying as many as six passengers, according to the company.
Navya boasted partnerships with transport specialty firms -- notably Keolis in Europe and the US and RAC in Australia -- which said will enable it to roll out Autonom fleets in cities.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)