I don’t know if this applies to the Glasgow case, but in an urban environment one source of apparent rapid movement might be the lighting of shop signs, advertising hoardings, Christmas lights, etc. If lights go on and off in a planned sequence, there could be an appearance of very rapid movement, though nothing is actually physically moving at all (other than electrons!) A well-known example in the UK is the lights of Piccadilly Circus in London ... Read even more
