Median and verge lighting for wide motorways.

This paper compares verge and median lighting systems. Only photometric aspects are taken into consideration. The arrangements compared assume 4 x 3.65 traffic lanes with a 5m central reservation, the lighting columns are 15m high, with verge lighting being placed 2m behind the hard shoulder, and C2 road surfacing. Arc-tube orientation, luminance design, average luminance, Threshold Increment and relative lane luminances are discussed. It is concluded that there is little advantage in lighting from the verge, and that in fact some problems arise. These include lower average luminance, higher glare, suspect relative lane luminance and shadowing.