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D3 Highway: Opening of the Nažidla–Dolní Dvořiště Section

31.07.2026

The D3 is heading toward the Austrian border. SWIETELSKY completes a major section of the international transportation link a month ahead of schedule.

The D3 highway has moved closer to the Austrian border. The new section from Nažidla to Dolní Dvořiště, at the state border, was constructed by SWIETELSKY stavební for the Road and Highway Directorate. The contract, valued at over 905 million CZK excluding VAT, represents another step toward creating a high-capacity connection between the Czech Republic and Austria and is also one of the key transportation investments carried out in South Bohemia in recent years.

The new 3.5-kilometer section connects to the already completed parts of the D3 and extends the highway network all the way to the Austrian border. Upon completion, it will significantly improve the traffic situation in the Dolní Dvořiště area, through which a substantial portion of transit traffic has previously traveled along the existing I/3 road. At the same time, it represents another step toward fulfilling the long-term goal of creating a modern, high-capacity connection between Prague, České Budějovice, and Austria. The importance of the project is underscored by the fact that, toward the end of the project, the contract was expanded to include a direct connection of the highway’s terminus to the state border. Under the original plan, all traffic was to pass through the newly constructed Dolní Dvořiště grade-separated interchange.

From an implementation perspective, this is a technically challenging transportation project that includes not only the highway structure itself but also bridge structures, a grade-separated interchange, road realignments, and extensive infrastructure related to drainage and environmental protection. The coordination of numerous construction disciplines and SWIETELSKY’s specialized teams played a significant role. Divisions specializing in transportation infrastructure, bridge construction, and special foundation work participated in the project.

The complexity of the project was further tested by specific technical solutions and unforeseen circumstances. For Bridge SO 216 at the beginning of the section, a significantly safer option was chosen: routing traffic along a temporary road on the right side of the future bridge, which replaced the originally planned stabilization of the approximately ten-meter-high slope of Road I/3 using an anchored sheet pile wall. The course of construction was also affected by the fall floods of 2024. At the overpass in the Dolní Dvořiště grade-separated interchange, these floods necessitated the dismantling and reconstruction of the spatial formwork of the supporting structure, including the replacement of the subgrade and the repositioning of the load-distributing concrete panels.

The project’s environmental requirements also demanded special attention. To protect the rare freshwater pearl mussel in the Malše River, three retention basins and a discharge pipeline with a total length of 4.55 kilometers were constructed, supplemented by additional water management measures aimed at ensuring the sustainable management of stormwater and the protection of valuable natural sites along the river. The project thus combines modern transportation infrastructure with an emphasis on a responsible approach to the surrounding landscape.

“Every construction project brings its own surprises, and this one had several right off the bat. Unexpected events always set you back in the schedule; for example, right at the start, we had to call in bomb disposal experts because of ammunition from the end of World War II that was found. At the site of a former gas station along Highway I/3, we also had to deal with historical environmental contamination, and in the fall of 2024, we were hit by a flood. That makes me all the more glad that, despite these complications, we managed to complete the section ahead of schedule and open it to traffic a month early,” says Pavel Fišar, project manager at SWIETELSKY stavební.

Construction began in January 2024, and during that time, we successfully completed an extensive set of structures, including bridges, earthworks, and the structural layers of the roadway. Thanks to the hard work of everyone involved, the schedule was accelerated, and the new section was put into operation on July 31, 2026—one month earlier than the contractual completion date.

The expertise, reliability, and consistently high quality of the projects carried out are also confirmed by the “TOP Construction Company” award, which SWIETELSKY stavební has received for the fourth consecutive year. The award is presented annually by CEEC Research based on evaluations by public contracting authorities. These authorities assess individual companies according to their satisfaction with the implementation process, construction quality, adherence to deadlines, communication, and the final cost of the project.

The company is now applying the experience gained on the D3 project to the implementation of other major transportation infrastructure projects, including, for example, the D7 Knovíz–Slaný-West, the D7 Aviatická Interchange, the D1 Brno South Interchange, and the I/20 České Budějovice Northern Bypass.

“Transportation engineering is not just about technology, road construction, bridges, or highways. It is a field that significantly influences people’s quality of life, traffic safety, and the economic development of regions. Every project of this kind leaves behind a legacy that will serve the public for many decades. That is precisely why we view these projects not only as construction contracts but also as an opportunity to contribute to something that has a real and long-term impact on people’s daily lives,” says Aleš Krupka, CEO of SWIETELSKY stavební.