According to daily Berliner Zeitung, in an unpublished study, the agency (UBA) said such a toll on passenger cars, known as a Pkw-Maut, would be the best way to tax car traffic and protect the environment.
Such a charge could cost each motorist several hundred euros per year.
UBA president Jochen Flasbarth told the paper: “The widely-applied toll is the most proper solution, because the costs are paid where they occur.”
At present, motoring costs the state €47 billion more than petrol and vehicle taxes bring in, he said.
The introduction of the toll could help pay for the construction and maintenance of roads and the upgrading of motorway networks, he added.
In the view of the UBA, a toll based on how far motorists drove would be an ecological tax, meaning the rate could be dropped for clean and efficient “green” cars. It could also be raised in areas that were heavily burdened by traffic or were in particular need of environmental protection.
“If the Cologne ring is congested in the morning, it would become more expensive at this time. That leads to a more evenly distributed use of roads, and is also good for the environment,” Flasbarth said.
Transport Minister Peter Ramsauer, however, rejected the suggestion of a national toll on passenger cars.
“The coalition agreement doesn't order it,” Ramsauer said at a conference of transport ministers in Bremen.
His state colleagues also spoke against such a toll. “I don't regard a car toll as practicable,” said Thuringia's minister, Christian Carius.