I had a check of our Tasmanian Legislation, the Road Rules 2009: 
"15. What is a vehicle 

A vehicle includes -

(a) a motor vehicle, trailer and tram; and

(b) a bicycle; and

(c) an animal-drawn vehicle, and an animal that is being ridden or drawing a vehicle; and

(d) a combination; and

(e) a motorised wheelchair that can travel at over 10 kilometres per hour (on level ground)"