On mobile road works, mowing and cleaning operations, a crewed vehicle protects the convoy from behind. It is there to be hit — and there is a person in the cab.
A mobile work zone moves: mowing the embankment, sweeping the carriageway, lining work, inspection runs. Because it moves, it cannot be closed off like a fixed site. It is protected instead by a vehicle that follows at a distance and keeps moving traffic from running into the convoy.
That vehicle is built to absorb an impact — usually with a truck-mounted attenuator. That is its job. The problem is that someone sits in it, waiting for the same collision.
How real that is, the figures show: in Austria, roughly every second motorway accident is a rear-end collision, and around five to six per cent of all serious rear-end collisions involving lorries on motorways hit a mobile warning board. These are not outliers; this is an occupational risk with statistics behind it.
A mobile work zone has two roles that can be automated independently of each other — and that differ markedly in technical terms.
The vehicle keeps the prescribed distance to the convoy, carries the warning board and impact protection, and follows the work zone by itself. The decisive change is not that it drives, but that nobody is sitting in it.
Mowing embankments, verges and noise barrier slopes, cleaning and inspection runs. Long, monotonous stretches in an environment that is easy to map — and often on slopes that are awkward for crewed machines.
The real gain comes when the mowing machine and the protection vehicle run as a pair: the convoy gets smaller, fewer staff are needed, and the most dangerous position is no longer occupied at all.
In the German research project aFAS, eight partners from industry, research and road administration developed a driverless protection vehicle and demonstrated it publicly in live traffic in 2018. A converted lorry followed a mobile work zone on the hard shoulder — without a driver, at a defined distance, based on series-production components for control and functional safety.
That is the most important context for this application: it is not a concept, it has been demonstrated. What is missing is not proof of feasibility, but the path into regular operation.
We say it openly: in this application, the road to approval is longer than the road to function. Anyone pursuing it seriously does so together with the road operator and the licensing authority — not as an off-the-shelf purchase.
Closely related is vegetation and embankment management: the same environment, the same platform class — just without the protection role.