June the 30th, 2026 – The construction of the third lane on the extremely busy A1 Zagreb-Karlovac begins, and drivers are asked for their patience as the 248 million euro investment gets going.
It doesn’t matter that the motorways are going to be packed with countless cars from across Croatia and from abroad, big roadworks are coming. Drivers are being warned to expect disruptions on one of the country’s busiest motorway sections as a major expansion project moves forward. Reports reveal that the A1 motorway between Zagreb and Karlovac is set to receive a third traffic lane in both directions, a project designed to reduce congestion and improve safety.
The section between Zagreb and Karlovac has long been one of Croatia’s most overloaded road corridors, especially during the summer tourist season when traffic increases significantly. The route connects several major motorway flows, causing frequent bottlenecks around the Zagreb area and the Lučko interchange.
The project, led by Croatian Motorways (HAC), includes the construction of an additional lane in each direction, improvements to existing infrastructure and the construction of three new interchanges: Stupnik, Ašpergeri and Selce. The existing Jastrebarsko interchange will also be reconstructed.
The estimated value of the project is around 248 million euros. Before the official tender is launched, HAC is conducting preliminary consultations with potential contractors as part of the public procurement process.
Construction is planned to begin in 2027. During the works, drivers should expect temporary traffic arrangements, including narrowed lanes and reduced speed limits. The motorway will remain open, but travel times could increase, especially during busy periods.
The Zagreb–Karlovac section is around 39 kilometres long and was designed for a much lower traffic volume than it handles today. Authorities say the expansion should significantly increase capacity, improve traffic flow and make journeys safer.
For drivers, the message is clear: the upgrade is expected to solve long-term traffic problems, but getting through the construction period will require patience.
