Shades of Dr. WHO?

Remembrt K9?
I found myself driving down past the local Cricket Club and school field.  Thinks:-
"Is that thing moving?"  I stopped - it didn't. 
AHA!
Drive past, stop, wait for it, shoot it.  NOT a Driver in sight.
1. Time saved. Vs. Man out of a Job.  I suspect the former.

It was systematically adding white lines to the running Tracks.