bike-finger
A derivative of the driving-finger, more often used by individuals on a bike. Frequently displayed by bike-messengers/cycle couriers to comment on the ass-hattery of Traffic Officers.

Note: may be utilized with both hands (dual-bike-finger) and is often presented with verbal accompaniment.
Whilst noticing the black and white, parked in the cycling lane, the courier proudly offered the officers his bike-finger.