The mobile bridge helps vehicles pass through the road under repair

A new modular mobile overpass design allows vehicles to drive right above the highway section that needs repair instead of having to take a detour.

Workers install ASTRA mobile overpass. (Video: Swiss Federal Road Agency)

Named the ASTRA bridge , the design aims to help drivers travel easier and road workers work safer. The work was created by the Swiss Federal Road Agency, New Atlas reported on May 24. The initial version of the ASTRA bridge was tested on the Swiss A1 motorway section in 2022, followed by testing of the new improved version. The second version was installed on A1 in April 2025 and will remain until August.

Not long after the roadwork was scheduled, the affected side of the highway was closed over the weekend. At night, trucks carrying different sections of ASTRA arrive, and workers assemble them to form an overpass that runs the length of the road repair area. Up and down ramps at both ends of the overpass allow vehicles to pass through the road. The following week, ASTRA opened for driver use. Even though they have to slow down to 60 km/h when crossing an overpass, they do not need to squeeze into one lane, or stop and wait for their turn to pass.

At the same time, road workers began demolishing and replacing the road surface below the overpass. They don't need to worry about being hit by passing vehicles, and can avoid the sun and rain. Additionally, because the renovation work does not impede heavy traffic during the day, they can work during the day instead of having to work the night shift.

ASTRA mobile overpass.

Because there is not enough space under the overpass for tall construction vehicles such as cement mixers to operate, workers use the transport lane running alongside the construction site. Depending on the circumstances, that lane may be an available driving lane on the road. After completing the repair process on the original highway section, the entire overpass was raised 10 cm hydraulically, then removed from the highway on motorized wheels to move to the next section. The process can be repeated many times until the entire project is completed.

In its current form, the ASTRA bridge is 257 m long, 7.57 m wide and 4.65 m high. The working area under the bridge is 100 m long, 5.1 m wide and 3.1 m high. The installation and dismantling process required 16 low-bed trailers to make a total of 45 trips to transport all structural components to and from the construction site. In addition, the process also requires the use of 3 cranes along with two 14-person assembly teams.