A bicycle lane of adequate width and clearances is wide enough for a car to travel along, just as a typical 2 lane road is wide enough to fit 3 or 4 vehicles side by side. But selfish drivers only see space they could be using.
The conventional bicycle lane is placed to the kerbside of other traffic lanes, separating the slower bicycles from faster traffic to one side and slower pedestrians to the other. Where there is parking on the road bicycle lanes are usually placed between the parked cars and the traffic to keep the drivers entering and exiting their parked vehicles protected rather than the alternative of placing the parked cars between the traffic and the “protected” bicycle lane. As an adjunct lane other vehicles will have need to cross the bicycle lane for various purposes and this is covered by the Australian road rule of:
Driving in marked lanes designated for special purposes
It specifies the entire range of situations where another vehicle may use special lanes, and places an absolute limit on the distance (permitted distance) other vehicles may use the bicycle lane for at 50m. These exemptions for other vehicles to use a bicycle lane are to:
- Enter or leave the road
- Overtake a vehicle turning right
- Stop for an emergency or breakdown
- Move to or from parking
- Avoid an obstruction
- Pickup or drop off passengers with a taxi or public bus
- Move to or from road “kinds”
This last point is expanded on in the road rules with examples of:
moving to or from a service road, the shoulder of the road or an emergency stopping lane
And notably does not mention other lanes of the road, similarly obstruction is defined specifically excluding traffic:
obstruction includes a traffic hazard, but does not include a vehicle only because the vehicle is stopped in traffic or is travelling more slowly than other vehicles
So confusingly no guidance is given for crossing a bicycle lane to reach another traffic lane, although road markings try to make the intention clear with broken lines where other vehicles should cross.
These rules for other vehicles using special lanes are and extension to the normal rules of
Moving from one marked lane to another marked lane across a continuous line separating the lanes where it is normally an offence to cross a solid line, and once a broken line is provided cars are able to move into (and across) these lanes by simply giving way. But driving down a bicycle lane to jump the queue, still an offence.