By some estimates it is not going to make very much money at all.
Germany's biggest automobile club, ADAC, which opposes charging foreign drivers on motorways, estimates it will bring in €260 million a year, with set-up and running costs of €300 million, thanks to the huge bureaucracy involved.
The toll will do little to plug a gap in the transport budget of €7.2 billion.
To get the charge past EU anti-discrimination laws, all drivers will pay the toll. But Germans will get the money they pay taken off their annual road tax. That means working out a new tax calculation for Germany's 40 million cars.
The bureaucratic side of the toll is one which Germans will deal with and some may even relish. The country is, after all, weighed with heavy bureaucracy at all levels of society, from registering addresses and getting railcards to setting up businesses.
It is ranked as the 114th easiest place in the world to start a firm.
But in a rare break with paperwork, German bureaucrats will charge drivers electronically by taking photos of all 40 million number plates.
This is something German drivers are far less likely to accept, and opposition to this, which includes most of the country's major media outlets, is where opponents of the road charge are pinning their hopes.
Germans are not comfortable with the electronic gathering and storage of their data. They rated it as a greater threat to freedom than international terrorism in a poll last month.
But the worst part of the plan is that it is not needed. The government has never had so much money.
In the first half of 2014, German tax revenue rose by 2.5 percent to a record €284.5 billion. The highest increase came from motor vehicle tax, with a revenue increase of 70.3 percent. Why fiddle with a source of income that has just netted you 70 percent more than last year?
What the government does need to do is increase the infrastructure budget – something everyone from the IMF, EU and United States has urged it do.
It is hard to believe Europe's biggest economy, with the rude health of its public finances, can't find enough money to repair its roads, without discriminating against foreigners.
How can it be that Germany is the only large EU country which needs to resort to such a backward policy to maintain infrastructure?
Last week, transport minister Alexander Dobrindt reached an agreement with his coalition partners on how to introduce the toll, after overcoming opposition from border states that it would put visitors off. It is coming in 2016. How did it get this far?
“With me there will be no road toll. I've said that again and again in lots of interviews.” Angela Merkel, September 2013.
“It will come.” Angela Merkel, September 2014.
It was introduced by the Christian Social Union (CSU) – the centre-right party of Bavaria, to shore up their support before the last election in September 2013.
Leader Horst Seehofer made it an issue late on in the election campaign, taking his future coalition partners by surprise. His party colleague, Dobrindt was then made transport minister and charged with getting it done.
You can see the appeal of it for Seehofer and his Bavarian chums. Foreigners can’t vote.
Their argument, that foreigners should pay to drive on German roads because Germans do, is as dangerous as it is ridiculous. Foreigners use German water, energy and national parks without directly paying for them. By the CSU’s logic, they should pay.
What would else would they like tourists to pay for? Maintaining the police force for keeping them safe on their two-day visit to Berlin? How about a television licence fee for visitors? Or a tourist tax for walking on pavements?
Merkel, Europe’s most powerful leader, has let a policy she opposes get very close to becoming law to keep her Bavarian allies on side. Party politics means foreign drivers will be punished from 2016 by a reactionary and insular policy.
As a role model for many in Europe there is a danger that other countries will follow Germany's lead, putting Europe on the path to more barriers between member states, when Merkel, as one of the standard bearers of the European project, is meant to erode them.