If a vehicle ahead is travelling slower than you want to travel, you can overtake them, but there is safe overtaking and unsafe overtaking.
Signs that prohibit you from overtaking or warn of scenarios where overtaking is dangerous
Driving scenarios when overtaking is dangerous
Don’t overtake when you would force the other vehicle to move onto the verge or hard shoulder or if you would have to drive on the verge or hard shoulder
Don’t overtake if you can’t see a sufficient distance of clear road ahead of you when you have finished the overtaking manoeuvre. Usually this would be 100m or more of clear road to give you a buffer
Don’t exceed the speed limit when overtaking
Don’t overtake a vehicle that is indicating to turn right, or a long vehicle when it is turning left (it may have to pull out to the right to make the left turn)
Don’t overtake when there are road markings that prohibit you from overtaking, for example, a solid white line on your side of the road
Don’t overtake when a vehicle behind you is already overtaking you
Don’t overtake an accelerating vehicle unless you are very sure that your vehicle has superior acceleration and that you will end up going faster than the vehicle you are overtaking (e.g. you’re overtaking a tractor or truck, but you are in a car)
Don’t overtake when you don’t have enough power to get the job done – this is especially relevant when driving uphill or when towing
Don’t overtake when the vehicle ahead may have to move right to overtake stationary vehicles or cyclists
Don’t overtake when the road narrows and it would become dangerous
Don’t overtake if you can’t complete the manoeuvre before a passing lane ends or a lane ahead is closing due to roadworks
Don’t overtake when others are wanting to overtake if you can’t get past the vehicle at a courteous speed difference, i.e. don’t hold others up behind you by taking too long to overtake.
Don’t overtake when approaching a sharp bend or when you can’t see through the bend
Don’t overtake by using a lane you’re not permitted to use, e.g. a bus lane
Don’t overtake using a median strip.