Higher Mass Limits (HML) is a nationally agreed scheme that permits approved heavy vehicles to operate with additional mass on certain types of axle groups, on a restricted road network and subject to specified conditions.

In 1998, Ministers approved the following axle mass limit increases for vehicles fitted with road friendly suspensions:

• 0.5 tonne increase on tandem axle groups to 17 tonnes
• 2.5 tonne increase on tri-axle groups to 22.5 tonnes
• 1 tonne increase on single drive axles on buses to 10 tonnes
• 1 tonne increase on six-tyred tandem axles to 14 tonnes
• 0.7 tonne increase on steering axles of long combination vehicle prime movers (i.e. road trains and similar) fitted with wide single tyres, regardless of suspension type.
• the increases mean that subject to bridge funding, six-axle semi-trailers would increase to 45.5 tonnes, B-doubles would increase to 68 tonnes, double road trains would increase to 85.7 tonnes and triple road trains would increase to 125.2 tonnes

Ministers also approved:

• increases for tri-axles to be restricted to members of a mass management compliance accreditation scheme www.ntc.gov.au/viewpage.aspx?AreaId=35&DocumentId=108
• substantial penalties to apply for gross overloading
• establishment of a national bridge upgrading program, subject to Commonwealth funding
• operators to pay a contribution (via charges) to ongoing bridge costs
• increases subject to the fitting of certified road friendly suspension systems www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/vsb_11.aspx

Participation in the HML scheme requires registration in each applicable state and territory. Further information, including application procedures, operating conditions and applicable route maps, is available from road agency websites:

• New South Wales: www.rta.nsw.gov.au/heavyvehicles/downloads/mass_dl1.html
• Victoria: www.vicroads.vic.gov.au/Home/HeavyVehicles/RouteInformation/HigherMassLimitVehicles.htm
• Queensland: www.transport.qld.gov.au/Home/Industry/Freight_and_heavy_vehicles/Heavy_vehicles/Higher_mass_limits
• Western Australia:www.mainroads.wa.gov.au/UsingRoads/HeavyVehicles/Pages/HeavyVehiclesHome.aspx: Please note due to generally available higher axle loads, a HML scheme is not offered in WA)
• South Australia: www.transport.sa.gov.au/freight/road/vehicle_configuration/heavy_vehicle_access_framework/index.asp
• Australian Capital Territory: www.tams.act.gov.au/move/vehicles/Heavy_Vehicles/heavy_vehicle_exemption_notices2
• Tasmania: www.transport.tas.gov.au
• Northern Territory: www.nt.gov.au/transport

Heavy Vehicle Access Schemes and Arragements - January 2009  (273.83 KB)