Some reports suggest the price of petrol will have to go up to cover the cost of the autoroute expansion if it goes ahead after the vote next month.
The Federal Roads Office points out revenue from the tax at the pumps goes towards maintaining and developing the road network – but with the switch to more electric vehicles, revenue is dropping.
Some forecast suggests the funds could fall below CHF 500m by 2027 – that would mean a price rise of around 4 centimes a litre.
There are plans to tax electric vehicles – but that needs a vote, which won’t happen before 2027 at the earliest.