<P> The hammer lane is another term for the passing lane . Its etymology originated with truckers in North America in reference to slamming the accelerator with a foot like hammer .) </P> <P> HOV lanes are not usually considered hammer lanes, but are also used for express travel by commuters . </P> <P> In hilly terrain, some undivided highways are built with three lanes, with the extra added pavement known as the "climbing lane" or "crawler lane". Two lanes are used for traffic heading in the uphill direction, with one lane being a passing or climbing lane, and one lane is used for downhill traffic . On dual carriageways, the climbing lane may be marked with a broken double white line . </P> <P> In Australia, most intercity highways are constructed with only one lane in each direction . Head - on collisions are a risk, particularly with fatigued drivers . Overtaking lanes are an additional lane in one direction for a short distance (one or two kilometres) to assist faster traffic to safely overtake slower traffic . Road markings are often painted so that the additional lane appears in the centre of the road (guiding traffic to the left), and traffic needs to deliberately change lanes to overtake . At the end, the markings are the other way, so that the left lane must yield and merge into the overtaking lane . Large signs alert drivers that they are approaching an overtaking lane, often at 5 km and 1 km distances before the lane starts . </P>

What is the outside lane on a highway