This is a road striper. It applies the yellow lines between lanes, and other lines that help guide motorists. The road striping vehicle can go up to 12 miles per hour while painting a stripe on the road. Both vehicles are moving forward while loading and grinding. The yellow machine is a grinder.
Road crews use it to grind away pavement.
Here, it is removing pavement that has buckled because the tree's roots are growing under the road. The grinder is grinding off the top few inches of asphalt so that the road can be re-paved. The backhoe is an excavator with a bucket attached to a hinged pole on a boom. As the operator digs a trench with the backhoe, the bucket moves backward to the machine. This backhoe can be lowered into tight trenches using the hinged pads on either side.