Heavy vehicle road rules you need to know

When we think of a heavy vehicle with a semi-trailer, we picture a huge marvel of man-made machinery charging across the long roads that cuts through the barren Australian outback. There’s nothing, but a few unlucky kangaroos around to cross their path.

However, in residential areas hazards (both inanimate and animate) are abundant, and a driver must be able to contend with all of these potential dangers.

For this reason, heavy vehicle road safety rules have been put in place, some signed clearly around our urban centres, to help drivers navigate their vehicles safely while driving. We’ve summarised these road safety rules for you so you have them all in one place whenever you need a quick refresher.

First, let’s start by defining a heavy and long vehicle. 

A heavy vehicle is defined as:

• A vehicle that has a gross vehicle mass (GVM) or aggregate trailer mass (ATM) of more than 4.5 tonnes.

A long vehicle is defined as any one of the following:

• A vehicle or trailer that is longer than 7.5 metres
• A vehicle or trailer where any load or projection is longer than 7.5 metres
• Any combination which is 7.5 metres long or longer
• Any component of a combination (a prime mover or prime mover trailer), which if standing alone is five metres or longer.

Heavy vehicle parking

It’s most important to know that if you're driving a heavy or long vehicle, you can stop in built-up areas for up to 1 hour. You can only be parked for longer if:

• You're dropping off or picking up goods — for the entire period your vehicle is stopped
• Signs say otherwise

City and town councils are usually diligent in enforcing this local law. Failure to comply will likely result in a penalty of demerit points and a fine. The severity of these will, of course, depend on the laws within each city council.

Heavy vehicle road rules and signs

Below are some examples of the most common heavy vehicle road rules and their corresponding road signs that operators should abide by.

Light traffic roads

If a weight restriction sign is displayed for a road, you must not use that road if the total weight of your vehicle, including its load, is the same as or heavier than the weight shown on the sign. 

Load limit sign

Also, be aware that you must not drive past a bridge load limit sign, or a gross mass limit sign, if you know the maximum gross mass of your vehicle is above the limit shown on the sign.

No trucks sign

Drivers of long or heavy vehicles, except buses, must not drive past a no trucks sign unless the vehicle is equal to or less than the mass or length specified on the sign.

When the sign does not provide detailed information, no truck (i.e. GVM greater than 4.5 tonnes) is permitted to drive past the sign, unless the drivers’ destination lies beyond the sign and it is the only route.

Trucks must enter sign

Heavy vehicle drivers must enter the area indicated by information on or with this sign. Typically, these signs are used to mark the location of a weigh station where members of the state road transport authorities inspect your vehicle for any compliance issues.

Trucks must use low gear

When driving a truck on steep routes you must drive in a gear low enough to limit your speed without relying on your primary brake. This rule is designed to reduce brake fade and the potential of serious accidents.

When working in a residential area, it’s an offence for a person who is not an 'existing operator' to operate a heavy vehicle on residential land between 10:00 pm and 6:00 am. This is intended to protect the amenity of residential neighbourhoods from noise associated with operating heavy vehicles at night.

Repairs and maintenance to heavy vehicles are not, however, restricted on residential land. Nevertheless, such work must be carried out in accordance with existing environment and noise legislation.

Heavy vehicle speed

Across Australia the Australian Design Regulation 65/00 requires the below heavy vehicles to be fitted with a speed limiting device:

• Heavy omnibus over 5 tonne, up to 14.5 tonne GVM and built on or after 1 July 1991
• Heavy omnibus over 14.5 tonne GVM and built on or after 1 January 1991
• Heavy goods vehicle over 12 tonne GVM, over 300HP and built on or after 1 July 1991
• Heavy goods vehicle over 12 tonne GVM, over 300HOP and built on or after 1 January 1991
• Buses with a GVM over 14.5 tonne built after 1987
• Prime movers with a GVM over 15 tonne built after 1987

These speed limiters are set to a maximum speed limit of 100 km/h for most heavy vehicles, however for road trains the speed limit is lower at 90 km/h.

However, for certain road conditions, special speed limit signs may be posted for trucks, road trains and buses. So, you must not drive at a speed greater than the speed shown on the sign.

When on a one lane road and driving a long vehicle, you must leave a gap of at least 60m between your vehicle and the vehicle in front of you. If you are driving a road train, you must widen that gap to least 200m. This rule doesn't apply if you're driving on a multi-lane road or a road in a built-up area. In this case, you must leave enough space to allow you to stop safely and avoid a crash.

One final rule that is easy to miss, is that it’s illegal and dangerous to direct following vehicles to overtake using your hand or the indicator. What you think is probably a polite gesture, is actually a way of encouraging an inexperienced driver to attempt an unsafe move.

Even though you’re obeying the road rules, it doesn’t mean accidents don’t happen. Truck Assist’s Roadside Assistance plans are designed for any truck owner, with breakdown services available anytime and anywhere.

Truck Assist offers a well thought out solution for small businesses who are seeking to protect their company truck and machinery. Get a quote for Roadside Assistance online to see how we can keep you on the road.