Germany's environment agency on Saturday called for a speed limit of 120 kilometres (75 miles) per hour on all the country's autobahns, many of which allow drivers to go as fast as they like.

"A speed limit would bring considerable progress in terms of environmental protection and road safety," the agency's president Andreas Troge said in an interview with the Berliner Zeitung daily newspaper.

A limit of 120 kph would reduce Germany's carbon dioxide output by up to three tons per year or 10 percent of the motorway network's total emissions, Troge said.