German carmaker Daimler has unveiled what it calls the world's first self-driving truck authorized for use on public roads, presenting the ground-breaking vehicle in the US state of Nevada.

The Freightliner Inspiration truck was launched on the iconic Hoover Dam, an hour's drive from Las Vegas, said Wolfgang Bernhard, head of Daimler's truck and bus division.

"The Hoover Dam provides the ideal setting for a debut as significant to the trucking industry as this," he said. "Not only was it built primarily using trucks, but it signifies inspiration like few other structures in the world."

"To show the significance and opportunities of autonomous driving functions for the global trucking industry we were willing to go ways that people did not dare to think about before," he added.

The Stuttgart-based company said in a statement that Nevada had approved two Freightliner Inspiration trucks for regular driving on public roads.

The vehicles have smart systems including sensors and active speed regulators, and are authorized for use without a human driver -- although one has to be present to monitor the system and take the wheel if necessary.

"The authorization to drive on roads in the United States is an important step for self-driving trucks," said Bernhard.

Daimler, whose vehicles include the high-end Mercedes-Benz range and compact Smart cars, is also the world's biggest maker of trucks with brands including Mercedes-Benz, Freightliner, Fuso and BharatBenz.

The German giant is a pioneer in self-driving technology, both in cars and trucks.

In an interview Wednesday in the German business daily Handelsblatt Bernhard trumpeted the advantages of self-driving vehicles. Besides increased safety compared to human drivers, they can save up to 5 percent in fuel usage.

The truck driver's job is also made less tedious and therefore more attractive, he added.

He added that a totally self-driving truck, without the need for human monitoring, "will not be with us before 2025." Self-driving cars in urban settings, where traffic conditions are more complex, are even further off, he added.

Daimler is currently seeking authorization in Germany similar to that obtained in Nevada, he added.

The German carmaker tested a Mercedes-Benz self-driving truck in Germany in July, but on a stretch of motorway with no other traffic on it.