As far as MR and Les Engagés are concerned, from 2029 every driver must purchase a road vignette to drive on the Walloon highways.
The Walloon government has announced that a road vignette will be introduced from 2029 for all motorists who want to drive on Walloon highways. This new policy, laid down in the Walloon coalition agreement, is mainly supported by the MR and Les Engagés parties. The aim is to have foreigners contribute to the maintenance of Walloon roads, while Walloon residents would be compensated by a reduction in car taxes. The proposed system is similar to that of Switzerland, where a road vignette costs 44 euros annually.
There is still uncertainty about whether Flemish and Brussels residents must also purchase a road vignette to drive through Wallonia. Georges-Louis Bouchez, chairman of the MR, stated in the French-language media that it is not the intention to make other Belgians pay. He proposes to arrive at a common system together with Flanders and Brussels. This idea has long been supported by experts, who indicate that a road vignette or other forms of road pricing would be better introduced nationally.
In Flanders, the subject of a road vignette has not yet been discussed in the negotiations for a new government. However, the Flemish parties are predominantly negative about a road vignette, because although it makes foreigners pay, it does not change car taxation for Flemish people. A kilometer tax is more likely to be considered, with motorists paying more the more kilometers they drive. This system shifts the burden from car ownership to car use and encourages people to use their car less often.

In the past, proposals were more in the direction of a kilometer charge, also on local roads.
There has been a kilometer charge for trucks since 2016, which was jointly decided by Flanders, Brussels and Wallonia. Perhaps such a joint system could also be introduced for passenger cars in the future, if the road vignette proves not to be an option. In the current Flemish government negotiations, only the Vooruit party appears to be in favor of a kilometer tax. In their election manifesto, the Socialists advocate a "rush hour tax", whereby drivers are taxed more if they drive in places prone to traffic jams during rush hours.
N-VA and CD&V spoke out against a kilometer tax during the last election campaign. Although N-VA was a supporter in the past, the party changed its position in the run-up to the 2019 elections due to “too little support among the population”.
There may be more political support for a kilometer tax in Brussels. MR and Les Engagés are also trying to form a government there, although the talks are difficult. PS may join as a third partner, but this party is not enthusiastic about a kilometer tax. The previous Brussels government already made plans for a smart kilometer tax, but these were rejected by both Flanders and Wallonia. The idea was to charge drivers more based on traffic congestion.
It remains to be seen how concrete the Walloon plans of MR and Les Engagés will become. The introduction of the road vignette is planned for the end of the government period in 2029, which means that a lot can still change before it is actually introduced.