Heavy vehicle mass limits: GML, HML and NHVAS

Why mass matters

Overloaded vehicles take longer to stop, are less stable and damage roads and bridges. Under Chain of Responsibility, consignors, packers, loaders and schedulers can all be responsible for a vehicle being over mass, not just the driver.

The mass limit schemes

There are three main mass limit schemes:

• General Mass Limits (GML): the default limits for a vehicle and its axles
• Concessional Mass Limits (CML): a little more mass, for operators accredited under the NHVAS Mass Management module
• Higher Mass Limits (HML): more again, for eligible vehicles with road-friendly suspension, on approved routes and under the conditions that apply

The National Heavy Vehicle Accreditation Scheme (NHVAS) is how operators show they manage mass, maintenance and fatigue to a standard. Exact limits depend on the vehicle, its axle groups and the route, so check the current limits with the NHVR.

What a weight declaration should record

• The transport company, driver, prime mover and trailer registrations
• Gross vehicle mass (GVM), tare and the anticipated load
• The weighbridge docket, as a photo
• The mass limit scheme the vehicle runs under, and the NHVAS number if it has one
• The driver's signature

Checking against the weighbridge

Declared and calculated weights are only estimates until a load crosses a weighbridge. Comparing the expected weight with the weighbridge weight, load after load, shows whether your standard weights are right and whether loads are creeping over.

LOGFYX's Vehicle Weight Declaration records the declaration and docket and stops tare plus load going over GVM. Product Mass Verification sends a load's expected weight to the site it's going to, and shows straight away whether the weighbridge weight is within 0.5%, light or heavy, with each site's trend over the year.