The transport ministers of Austria, Luxembourg and the Netherlands demand clarifications from the European Commission over its endorsement of a German scheme to charge drivers, with Austria being ready to challenge in court what it considers a discriminatory toll.

The ministers have outlined their demands during a meeting in Luxembourg on Wednesday (7 June), in the run-up to Thursday's transport council.

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The commission had opened an infringement procedure against the German scheme, saying it had been introduced together with another law, ensuring that vehicles registered in Germany benefited from a deduction of the road charge from their annual vehicle tax bill.

"This 1:1 deduction of the vehicle tax from the road charge would lead to a de facto exemption from the charge, exclusively for cars registered in Germany," the commission said at the time.

But EU agriculture commissioner Phil Hogan told MEPs last month that the commission had closed its probe on 17 May, after Germany passed laws in March to amend the toll, which will come into place in 2019.

"The commission came to the conclusion that these laws have addressed its concerns by removing discrimination based on nationality. Of course, the commission will now continue to monitor the correct implementation of this law, and the application of this law is very important," said Hogan, speaking on behalf of his colleague, transport commissioner Violeta Bulc.

But the three countries are not convinced by this explanation, with Austrian transport minister Joerg Leichtfried saying that the road toll plan, even in its revised form, could still discriminate against "all non-Germans" and wants the issue to be clarified by the European Court of Justice, the EU's court.

The issue would first, however, need to be subject to a mediation procedure with the commission, which is already underway according to Leichtfried, and will take approximately three months.

The three transport ministers are asking the EU executive for a written statement as to why it suspended the probe against Germany.

Leichtfried expressed doubts about achieving a positive result in the mediation procedure, and criticised the commission in an interview with Passauer Neue Presse, a German newspaper.

"It is a poor test that the EU commission, which was [meant] to be the guardian of the treaties, collapsed in front of large countries," he said.

The commission is unlikely to act on the issue before the German parliamentary elections in September.

Austria will head for the polling booths a month after that, and a tough stance against Germany and Brussels could help the ruling parties, including Leichtfried's social democrats.