You are planning on actually painting the detector? How much paint are you planning on spitting out of this contraption? Mile after mile of how many gallons of paint? Sidewalks, trees, street vendors, cars, buildings, and everything else are going to be coated with layers of paint every day? What color did you have in mind? Because your paint spewer is riding in front of the convoy, all of the vehicles are going to be driving through this great cloud of paint. How will they be able to see through their painted windshields? How will the engines deal with all of the paint they'll be sucking in? How will the soldiers breath?
P.S. n seconds is just as deadly as n times.