Drop Down Polly

   Drop Down Polly is not the name of Wyatt Earp's girlfriend but is actually the secret ingredient that makes the lines on the road reflect light. They consist of small glass spheres and cost an arm and a leg. When a line marker is spraying a line, another nozzle blows them onto the drying paint, there are also drying agents/additives mixed in with them. The paint dries in minutes but still needs the protection of small cones to keep traffic off them. The lifting and stacking of the small cones must require good upper body strength.
A computor can control the hights of both nozzles which increases or decreases the width of the line being painted. The amount /thickness of paint is recorded. The truck has two steering wheels so the driver/operator can sight down either side. He could be painted a solid line marking the edge of the carriageway ...( "The part of the road used by traffic, including the shoulders.") or the dotted centreline, yellow "no passing " lines etc. He/she has to do this while keeping an eye on the mirror and has radio communication with pilot vehicles that warn he is on the road. The concentration required must be immense. The dotted centre line usually has a solid bar, 10 metre gap, solid bar again etc. We often work out our sign spacing/ distances by counting them. I was told it takes a good three years before you are proficient at line marking. I believe it!