FRANKFURT (Reuters) - Cars could be driving themselves down the world's streets far sooner than expected, thanks to a change in a global treaty backed by European countries.

A little-noticed amendment to the United Nations Convention on Road Traffic agreed last month would let drivers take their hands off the wheel of self-driving cars. It was pushed by Germany, Italy and France, whose high-end carmakers believe they are ready to zoom past American tech pioneers and bring the first "autonomous vehicles" to market.

"Today I am only allowed to take my hands off the wheel to a limited extent. Thankfully the Vienna Convention on Road Traffic has been changed," said Thomas Weber, head of Group research at Daimler and head of development at Mercedes-Benz.

For years, so-called "autonomous vehicles" have been a futuristic dream pioneered by silicon valley companies like Google.

But as the technology becomes more affordable, Europe's luxury automakers say they are well placed to take advantage of it because of their deeper experience in engineering, manufacturing, marketing and sales. There is no point in waiting while California upstarts catch up.

The U.S. state of Nevada passed a law in June 2011 to allow test drives of autonomous vehicles there. Google tested one in 2012.

In August 2013, Mercedes-Benz responded to the Google push by developing an S-class limousine which drove between Mannheim and Pforzheim without any driver input. The 103 kilometer stretch is known as the Bertha Benz route, named after the driver of the first ever motorcar more than 125 years ago.

But moving from test drives to marketable products was held back by Article 8 of the 1968 Convention on Road Traffic, which stipulates: "Every driver shall at all times be able to control his vehicle or to guide his animals."

The amendment agreed last month by the U.N. Working Party on Road Traffic Safety would allow a car to drive itself, as long as the system "can be overridden or switched off by the driver". A driver must be present and able to take the wheel at any time.

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Provided the amendment clears all bureaucratic hurdles, all 72 countries that are party to the convention would have to work the new rules into their laws. The convention covers European countries, Mexico, Chile, Brazil and Russia, although not the United States, Japan or China.

HOPE IN EUROPE

The amendment was submitted by the governments of Germany, Italy, France, Germany, Belgium and Austria, according to the April 17 U.N. document - showing just how important the new technology is for Europe.

Germany's premium carmakers in particular have business models that rely on leading the market in vehicles with the most sophisticated features available. They can't afford to fall behind.

Audi , Mercedes-Benz, BMW as well as auto suppliers Bosch [ROBG.UL] and Continental, are working on technologies for autonomous or semi-autonomous cars.

Mercedes has developed technology which can scan the road ahead and behind with cameras and radar, and prompt a vehicle to pull out and overtake a large truck without a driver having to touch the steering wheel.

It now wants to introduce more automated driving features into its cars, such as automated parking, automatic stop-and-go driving in traffic and motorway driving functions. Eventually, it hopes to have cars with elaborate self-driving software that can be easily updated - like an iPhone - to take advantage of new technical capabilities or changes in the law.

"We have developed a car that can drive autonomously. Now the legal framework needs to follow suit," a Daimler spokeswoman said.

(Additonal reporting by Tom Miles in Geneva; Editing by Peter Graff)