This is the entrance road to South Riding as seen from within the neighborhood.  I counted 34 acorn fixtures on the 1/2 mile entrance road.  I would estimiate a total of about 200 acorns in the whole neighborhood.  Half of this light shines above the horizontal and is lost into the atmosphere causing urban sky glow.  Perhaps only 10% to 20% of the acorn's light actually hits the pavement where drivers need it for safety.