How do the temporary signs in the central reservation of motorways get there?

[mrsseanbean]

Yesterday I saw a man in a 'high-visibility' jacket by the side of the motorway with a maintenance lorry, holding a sign. He was looking at all the oncoming traffic as if he was about to cross the motorway, surely he doesn't wait until all clear and just run for it?!

What about the safety aspect while he is in the central reservation? What if he dropped the sign/ fell over?

I assumed one of those vans with a big flashing "X" on the back must drop them off.

Does anyone know the facts here?

Usually men in a van drive slowly along dropping cones to close off the outside lane. I have indeed seen some run across the carriageway as well, but they tend to do that at quiet times.