Farritor's team hopes to get the unit price down to $200 (£110).

"At that price I believe the savings will mean it will still be affordable if one dies in the line of duty," said the engineer.

It is envisaged the road markers would be delivered to a location by a specially equipped truck.

A camera on the vehicle would image the road and send a picture to a worker's laptop. The worker would then indicate on the screen where they wanted the bollards to be deployed.

Software developed by the Nebraska team would then obtain the precise coordinates and feed these to the "shepherd" unit so it could lead its herd of red robots into position.