Road conditions terminology
An alternative route available for traffic during a temporary closure of a road, or part of that road. Detours may be sealed or unsealed.
- High Clearance
A light vehicle with clearance sufficient to travel over rough and uneven road surfaces. The clearance on these vehicles generally exceeds common passenger vehicles.
- High Clearance 4WD
A light vehicle with two axles that is built for on and off road use and clearance sufficient to travel over rough and uneven road surfaces. The clearance on these vehicles generally exceeds common passenger vehicles.
Access along the section of road is affected by flooding or other obstructions. Road conditions are likely to change rapidly and may present an extreme hazard. Persons should not attempt to use/access the road.
- Lane Closure
Temporary closure of one or more traffic lanes. Traffic control devices are in place -to enable traffic to use unaffected lanes.
- Road Closed
Temporary closure of the road where passage of motor vehicles is not permitted. Barriers are in place and penalties shall be applied to drivers ignoring the road closure.
- Weight and Vehicle Type Restriction
A restriction placed on heavy vehicles to control axle group loads and/or vehicle size to protect the road during adverse conditions.
- With Caution
The condition of part of the road may have deteriorated so that due care must be exercised by the travelling public.
A light vehicle with two axles that is built for on and off road use. All four wheels can be engaged to improve traction in adverse conditions.
Empty Travel Permitted - An unladen load-carrying vehicle is not limited to the maximum number of axle restriction, where such a restriction exists. However, a load-carrying vehicle with a mix of loaded and empty trailers is subject to the maximum number of axle restriction, where such a restriction exists. Spare tyres and load restraint devices such as folded tarpaulins and side gates are allowed to be carried on empty trailers. A doubled-up trailer is considered to be loaded.
- Gross Vehicle Mass (GVM tonnes)
The maximum loaded mass of a vehicle, as specified by the manufacturer. It includes the tare and loaded mass of the vehicle, but not including loaded trailers. The GVM of a heavy vehicle is recorded with the Registrar, and is shown on the registration sticker.
- Heavy Vehicle
A motor vehicle with a GVM exceeding 4.5 tonnes. Typically these include buses, rigid trucks, semi-trailers and multiple trailer road trains.
- Legal Limits
Loads carried by the axles or axle groups of heavy vehicles that conform to the requirements of the Motor Vehicles Act and associated Regulations.
- Light Vehicle
A motor vehicle with a GVM less than 4.5 tonne. Typically these include passenger cars and 4WD vehicles, small motorhomes and minibuses, and other small passenger vehicles. Towing trailers and caravans is permitted under a light vehicle description, provided the GVM limit is compliant.
- Maximum Axles
The maximum number of axles of a motor vehicle and its trailers when in operation. Thresholds that apply will be 4, 7 or 13 axles.
- Night Closure
Temporary closure of the road for the safety of the public generally between the hours of 6pm and 6am. Barriers are in place and penalties shall be applied to drivers ignoring the road closure.
- No Overmass Permit Vehicles
Vehicles operating under an Oversize/Overmass permit are not permitted to travel until the restriction is revoked.
- Percentage - Axle Group Limit (AGL)
Restrictions imposed on the mass of an axle or axle group for heavy vehicles. The percentage reduction to 60% or 80% applies to the Legal Limits prescribed in the Motor Vehicles Act and associated Regulations. Percentage reduction does not apply to steer axle.
A general term for all work that is carried out within the road reserve area for construction, repair or maintenance. This includes work on or beside the road and any vehicle incident or recovery action.
- Steep Grade
A steep incline or decline that may restrict use by certain vehicle types.
- Tight Bends
A Series of one or more bends and curves in the road alignment that may restrict use by certain vehicle types.
- Water Over Road
Water is present over all or part of the road but the road is still trafficable, with caution. Refer also “Stream Crossings”.
- Changed Traffic Conditions
A temporary or permanent change to traffic conditions. For Example, a new posted speed limit, roundabout or duplication of the road carriageway.
- Boggy Conditions
An unsealed road surface that is wet and soft, which may lead to a vehicle becoming bogged. Can also apply to loose dry conditions.
A very fine material with a flour like texture often covering surface irregularities or deep holes.
- Changing Surface Conditions
The condition of the road surface may change along the length of the road, and following road maintenance activities. Wet weather may also cause a localised change in road condition.
An unsealed road surface having ripples or undulations along the road.
A localised section of road designed to accommodate temporary overtopping allowing water to flow over the surface of the road. Refer also “Stream Crossing”.
- Loose Surface
A layer of unbound or coarse material on the pavement surface. Can be very fine material (bull dust or sand), or large material in coarse gravel pavements.
Bowl-shaped depressions in the road surface, resulting from the loss of pavement material.
The consequence of irregularities, uneven in nature, in the longitudinal profile of a road with respect to the intended profile. Interpretation of conditions will not allow vehicles to use the road at customary speeds.
A longitudinal deformation of a pavement surface formed by the wheels of vehicles. May be on a sealed or unsealed road.
- Slippery Surface
Surface becomes slippery in wet conditions or from fuel or material spills.
- Stream Crossing
Natural watercourses that cross the road alignment. On sealed roads the crossing would generally be a bridge, floodway or culvert. On unsealed roads there may be no structure.
Water levels at floodways and stream crossings are likely to change rapidly and may present an extreme hazard. The ability to cross these floodways and streams will depend on depth of water, velocity of flow, driver experience and vehicle type. ALWAYS assess conditions prior to crossing or travelling along the affected section. See also “Water over Road”.
Steep, irregularly sided grooves in the road surface caused by erosion of the road surface by water.
An unsealed road that has been constructed to above the natural surface using local materials. Generally of a higher standard than unformed.
An unsealed road that has been formed and strengthened with a good quality gravel material. Generally of a higher standard than formed.
A road that is constructed with a bitumen surface.
An unsealed road that is generally a flat track following the natural terrain. Often occurs as a rough track with two wheel paths, and close vegetation.
A road without a bituminous surface that could be gravelled, formed or unformed.
Disclaimer: The reporting on road conditions is intended as a guide only. Whilst care has been taken to ensure these reports are accurate at the time of publication, road conditions can be subject to rapid change and information is updated on the site as soon as it becomes available. It is possible for some road conditions to remain unchanged for several days or weeks. The Northern Territory of Australia gives no warranty or assurance of the accuracy of this report and accepts no direct or indirect liability for reliance on the report.