Olympic cycling champion Chris Boardman intervened after a cyclist narrowly avoided being struck by a van.
Software engineer Tom Littlehales filmed the moment a white van passed him on the A505 near Dunstable, Bedfordshire.
He contacted police but was unhappy with their response so tweeted the gold medal winning Olympic cyclist.
Boardman questioned why the force was not taking the case any further.
Bedfordshire Police said: "Unfortunately we do not currently have the capacity to review non-serious incidents or incidents which are not currently in progress and in these cases motorists will be issued advice.”