On 17 August 2025, the stretch of the Slovenian H4 between Razdrto and Vipava was closed to traffic for major extraordinary maintenance works. Although the closure covers just ten kilometres, it has triggered serious congestion that is spreading as far as Friuli Venezia Giulia. In the very first week of the shutdown, from 18 to 25 August, the Lisert toll barrier recorded an increase of 33,581 vehicles compared to the same period in 2024, equal to a rise of 18 per cent or around five thousand extra vehicles per day. The growth involved not only industrial traffic, as had been expected, but also light vehicles that opted for the Fernetti border crossing instead of the Slovenian regional road designated as an alternative route.
Italian authorities believe the Fernetti crossing may have to handle up to four thousand additional heavy goods vehicles per day at peak times. Traffic is then funnelled onto the Trieste motorway link, putting heavy strain on the Lisert toll barrier, which has only four entry lanes to the Italian A4. To respond to this emergency, Autostrade Alto Adriatico has introduced corrective measures. From 25 August, the concessionaire converted one of the Lisert lanes from mixed use to electronic toll only, in order to smooth the passage of articulated lorries equipped with onboard devices.
But this measure alone is not enough to address the problem. The Slovenian motorway company Dars has therefore decided to allow a partial reopening of the section under works for industrial vehicles from 8 September 2025. The move also comes in response to mounting pressure from hauliers and local communities, which has even led to calls for the resignation of chief executive Andrej Ribič. Under the new traffic rules, one lane of the H4 will be reserved exclusively for heavy goods vehicles and buses with a gross weight of more than 3.5 tonnes heading towards Italy. The other lane will remain dedicated to emergency vehicles, while heavy traffic bound for Slovenia will continue to be diverted through Fernetti. Cars, in both directions, will be rerouted onto the parallel state road.
