.,02 Using common sense works better than any screen and costs nothing to buy or install. Ever see vehicles which look like their hoods were peppered with buckshot? Drivers get holes in the condenser the same way they get chips in the paint on the hood......following too close to something kicking up the rocks.
Don't want chips in the paint or holes in the condenser or chips in the windshield:
Do not tailgate
Avoid following trucks unless they have functional intact mudguards that do not sail....if not drop way back or switch lanes.
Avoid following farm equipment
Avoid following vehicles with large tires and/or aggressive tire treds, especially Jeeps with tires extending past the wheel wells without mudguards. Back off immediately if a vehicle, especially one with aggressive tire tred's wants to or starts to cut in front of you or their tires may kick up small gravel or crap that builds up in untraveled areas between lanes
Never follow concrete trucks or gravel trucks either with or without mudflaps, pieces of dried concrete, gravel or crap hung up on the frame/axles which can drop to tires for launching.
Allow extra following distances when forced to travel on gravel or crush and run roadbeds.
If forced behind one of the above on a two lane road with no passing, keep distance and pull off first chance to let the guy behind pass and work as your rock shield (and/or to dissipate a stinking exhaust).
And, even following the above, sometimes $hit will happen.....fifty plus years of driving and only one rock hit to my windshield from a jacka$$ in a POS Jeep with monster tires speeding in the adjoining lane.