The ASTRA bridge, developed by the Federal Roads Office of the Swiss government, is a nifty solution that lets you fly over ongoing road repairs on motorways instead of taking diversions.

The highly mobile and modular structure is similar to a bridge version of a Swiss Army knife and offers multiple functions in just one structure. 

Roadworks on motorways are always troublesome for drivers. Repairs, even on a single, can close multiple lanes for drivers, creating traffic bottlenecks and reducing the overall speed of moving traffic.  

The ASTRA bridge allowing works to be complete underneath as traffic flies overhead.Image: Antonio Nieto-Rodriguez/ LinkedIn.

For safety reasons, the repair team often closes larger tracks of the road than the ones being worked on, adding to driver frustration. If repairs are put off for longer periods, an entire stretch of the road can be off limits, forcing drivers to take diversionary routes to their destinations and increasing travel time. 

In ASTRA bridge, the Swiss Federal Roads Office has found a nifty solution to this problem by building a mobile bridge that can ease traffic above the repair works, giving peace of mind to both drivers and workers. 

 

How does ASTRA bridge work? 

Setting up the ASTRA bridge does require some closure of road traffic. But that can be done over a weekend when there isn’t much traffic expected. Once this is done, multiple sections of the bridge can be brought in on trucks and assembled overnight to make a flyover that runs over the area of scheduled work. 

Individual components of the ASTRA Bridge that can be assembled overnight to make the flyover at work site: Image: ASTRA. 

The structure has ramps on both sides to let vehicles move up and down the flyover without much hassle. The current version of the ASTRA bridge is a little more than 257m long and nearly 7.57m wide.

This allows vehicles to take the ramp and move over the planned repair works without merging into a single lane. 

The ASTRA bridge’s specifications require vehicles to move at speeds of 60km an hour or lower, but that’s a smaller price to pay than taking a diversion or hoping to be waved into the right lane to get out of a traffic block faster. 

Benefits of the ASTRA bridge

The benefits of the ASTRA bridge extend beyond the motorists who use it. Since traffic is flying over it, workers do not have to watch for approaching traffic when the work is on. 

The 4.65m-tall structure of the bridge gives workers ample space to work under the carriageway while also protecting them from excess heat and rain. Since the works do not interrupt vehicular movement, they can also be undertaken during the day, making the project less taxing for the workers, who otherwise have to work through the night. 

An added advantage of the shift in work times is that residents of the neighbouring areas are not disturbed during the night, making it a win-win situation for all. When work is completed on a section, hydraulic lifts can raise the bridge by a few inches and move it in front to take up the next patch of work.  

The ASTRA Bridge has hydraulic lifts that can move along the road as the work progresses. Image: ASTRA.

In 2022, when the ASTRA bridge was first trialled on the A1, the traffic flow could not be levelled. Working with the Swiss Federal Laboratories for Materials Science and Technology, the Federal Roads Office further improved the structure and added ramps that reduced the climb gradient from the previous 6% to 1.25%. 

The bridge is compatible with a wide spectrum of vehicles, such as caravans, sports cars, coaches, trucks, and semi-trailers, making it ideal for deployment anywhere road works are needed.