Street Light Pillars seen near Valley City, North Dakota on Febrary 24, 1979. 
Note the clear sky with star trails visible. Yet enough ice crystals were
present in the zero degree air to create light pillars above each streetlight
in the town.
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This phenomenon generally occurs in cold (below 10-15 F) moist weather
with very light snow that is really in the form of individual platelike
ice crystals. The sky may be cloudy or clear enough for stars to show
through. The pillars extend up and down in the vertical line passing
through bright artificial light sources. They are similar to sun and
moon pillars in that the light is reflecting off of the platelike
crystals having different random orientations.
<p>
Street light pillars can be mistaken for the aurora borealis, a very
different phenomenon. Street light pillars usually occur within 20 degrees
or so of the horizon, aurorae can be higher.
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More info may be found in the book
"The Nature of Light and Colour in the Open Air" by A. A. Minnaert.