Road Conditions Terminology

Road Conditions Terminology

• Policy: This document outlines standard terminology for reporting road conditions. It's intended for consistent use across all communication channels (formal road reporting, and for all road users).

Types of Restrictions

• Detour: An alternative route available due to a temporary road closure, either sealed or unsealed.

• High Clearance: A vehicle with sufficient clearance to navigate rough, uneven surfaces. Generally higher clearance than standard passenger vehicles.

• High Clearance 4WD: A 4-wheel-drive vehicle suitable for both on-road and off-road conditions. Clearance typically exceeds standard passenger vehicles.

• Impassable: Access is blocked by flooding or other obstructions. Road conditions may change rapidly and pose extreme hazards. Avoid attempting to access the road.

Further Restrictions

• Lane Closure: Temporary closure of one or more traffic lanes. Traffic control devices ensure unaffected lanes can be used.

• Road Closed: Complete closure of the road to vehicle traffic. Barriers are in place, and violating the closure carries penalties.

• Weight and Vehicle Type Restriction: Limits placed on heavy vehicles to manage axle group loads and/or vehicle size, protecting the road from damage during adverse conditions.

• With Caution: Road condition has deteriorated, requiring cautious driving.

• 4WD: A four-wheel-drive vehicle designed for use on both on and off-road use. All four wheels may be engaged for improved traction in adverse conditions.

Details of Restrictions

• Empty: Unladen load-carrying vehicles are not limited by the maximum axle restrictions. However, vehicles with a mix of loaded and empty trailers are subject to the maximum axle restrictions.

• Gross Vehicle Mass (GVM): The maximum loaded mass of a vehicle (manufacturer-specified), including the vehicle's weight and any loaded trailers. Heavy vehicle GVM is recorded with the Registrar.

• Heavy Vehicle: A vehicle with a GVM exceeding 4.5 tonnes (typically buses, rigid trucks, semi-trailers, and multiple trailer road trains).

• Legal Limits: Loads carried by axles of heavy vehicles must adhere to Motor Vehicle Act and associated regulations.

• Light Vehicle: A vehicle with a maximum GVM of less than 4.5 tonnes (typically passenger cars, 4WD vehicles, small motorhomes, minibuses, and other small passenger vehicles). Towing trailers and caravans may be permitted under the light vehicle description, if within GVM limits.

Additional Details

• Maximum Axles: Maximum number of axles (motor vehicle and trailer) in operation during travel—typically 4, 7, or 13 axles.

• Night Closure: Temporary closure, typically between 6 pm and 6 am. Barriers and penalties apply for ignoring closures..

• No Overmass Permit Vehicles: Vehicles using an oversize/overmass permit may not travel until the permit's restriction is revoked.

• Percentage - Axle Group Limit (AGL): Restrictions on the mass of axle or axle groups of heavy vehicles (typically 60% or 80% reduction). The percentage reduction does not apply to steer axles.

• Roadwork: Construction, maintenance, or recovery activities within the road reserve.

• Steep Grade: A significant incline or decline that restricts use by certain vehicle types.

• Tight Bends: Multiple bends and curves that can restrict use by specific vehicles.

• Water Over Road: Water present on the road surface, but road may still be passable—use extreme caution.

• Changed Traffic Conditions: Temporary or permanent changes to traffic conditions, such as speed limits, roundabouts, new road sections, etc.

Surface Conditions

• Boggy Conditions: Wet, soft unsealed road surface prone to vehicle bogging. Applicable in loose dry conditions as well.

• Bulldust: A fine, powdery material covering irregularities or holes.

• Changing Surface Conditions: Road surface condition may vary along the road, depending on maintenance or weather.

• Corrugations: Ripples or undulations on unsealed roads.

• Floodway: A section of road designed to accommodate temporary overtopping floodwaters.

• Loose Surface: A layer of coarse or unbound materials on the roadway surface (e.g., gravel).

• Pot Holes: Bowl-shaped depressions in the road surface.

• Rough: Uneven road surface irregularities that restrict standard driving speed.

• Rutting: Longitudinal deformation in the road surface, formed by vehicle wheels.

• Slippery Surface: Road becomes slippery due to moisture or spills.

• Stream Crossing: Natural watercourses that cross the road. Water levels at crossings may change rapidly and present extreme hazards.

• Washouts: Steep, irregular grooves in the roadway caused by water erosion.

Road Types

• Formed: Unsealed road constructed above the natural surface with local materials.

• Gravelled: Unsealed road strengthened with good quality gravel.

• Sealed: Road constructed with a bitumen surface.

• Unformed: Unsealed road following the natural terrain with a rough track.

• Unsealed: Road without a bitumen surface; it may be gravelled, formed or unformed.