Speed, following distance and stopping

Purpose and essential terms

A speed limit sets the maximum permitted speed, not the speed you must aim for. General limits apply even without a sign: the reference manual gives 60 km/h in urban areas, 100 km/h outside urban areas on roads other than freeways, and 120 km/h on freeways, unless a sign indicates otherwise.

Some vehicle classes have lower limits. You must know both the road’s limit and the limit applying to the actual vehicle or combination. Weather, grip and visibility can require a speed below every legal maximum.

Key idea: A speed limit sets the maximum permitted speed, not the speed you must aim for.

How to apply the rule

Identify the road type and any posted restriction. Check the vehicle’s class, gross vehicle mass and combination details. GVM is the manufacturer’s specified maximum mass of the vehicle and load, not merely the load aboard today; GCM refers to a combination’s specified maximum mass.

The reference states 100 km/h for buses and minibuses and 80 km/h for the specified goods vehicles above 9,000 kg GVM, qualifying goods-vehicle/trailer combinations and articulated vehicles above the listed mass. A breakdown vehicle towing another vehicle is also in the 80 km/h list. Obey a lower applicable posted restriction.

Key idea: Identify that its GVM places it in the reference 80 km/h vehicle-class restriction.

Conditions and easily confused points

A 120 km/h freeway sign does not cancel a lower vehicle-specific limit. An empty qualifying heavy goods vehicle does not automatically escape a rule defined using its specified GVM.

The 30 km/h rope-or-chain towing restriction is a separate rule and can be lower still. Work through every applicable restriction rather than choosing the largest number seen on a sign.

Key idea: Apply the full rule to the actual vehicle, road and conditions.

Purpose and essential terms

Following distance is the space between your vehicle and the one ahead. You need time to see a hazard, react and slow down. During your reaction, the vehicle keeps travelling; once you brake, it still needs distance to stop.

A time gap adapts to speed better than counting car lengths. The NaTIS manual gives a minimum of two seconds in good conditions for light vehicles and motorcycles, and three seconds for heavy vehicles. These are not promises that every vehicle can stop within that gap.

Key idea: Following distance is the space between your vehicle and the one ahead.

How to apply the rule

Choose a fixed point such as a signpost. When the rear of the vehicle ahead passes it, start counting seconds. Your vehicle should not reach that point before the minimum interval has elapsed. If it does, ease off smoothly and increase the gap. Repeat with another marker to check.

Increase the interval in rain, poor visibility, on slippery or loose surfaces, when the vehicle or load needs more stopping space, or when someone follows you too closely. Leave enough extra room to respond smoothly instead of braking abruptly. Reassess whenever speed or conditions change.

Key idea: Ease off the accelerator without abrupt braking.

Conditions and easily confused points

The time-gap method measures separation, not a legal entitlement to drive at a particular speed. At high speed, poor grip or low visibility you may need both a much longer gap and a lower speed. You should be able to stop within the clear road you can see.

A tailgater does not make brake-checking safe. Increase space ahead so you can slow progressively, keep a safe course and let the vehicle pass when a lawful opportunity exists.

Key idea: Apply the full rule to the actual vehicle, road and conditions.

Quick recap

• Identify that its GVM places it in the reference 80 km/h vehicle-class restriction.
• Do not use the 120 sign to override that lower limit.
• Reduce further if conditions make 80 km/h unsafe.
• Ease off the accelerator without abrupt braking.
• Reduce speed to suit visibility and grip.
• Build a gap longer than the good-condition minimum and measure again.