What is it?

The morning walk was enlivened by a young man in an orange vest apparently doing wheelies in the middle of the road with a lawnmower. On closer inspection, it wasn’t a lawnmower, but what was it?
 
The clue is in the extras. As the young man wheels the machine around, it finds gas and water pipes beneath the surface. The young man reads the computer display and uses the spray cans to create hieroglyphics on the road, showing where the pipes are located. Apparently the Council has plans for some kind of significant excavation in this road, and this is a strategy to ensure that they don’t damage gas and water pipes in the process. We hope it works.