Bridge restrictions

There are limits on the weight of vehicles on New Zealand roads and bridges. These limits were introduced to protect roads from overloading.

General Access mass limits

Historically most roads have been maintained to a level called 'Class 1' (also referred to as 'Class I'). More recently, the term Class 1 has been replaced with the term 'General Access'.  General Access has the same mass limits as Class 1, except that slightly increased gross masses are allowed on long vehicles. The General Access mass limits can be found in the Vehicle Dimensions and Mass Rule(external link).

Bridges with speed or weight restrictions below the General Access limits are called 'Posted bridges'. These restrictions are used where necessary to protect them from damage through over-loading. This also helps to keep road users safe. 

Posted bridges 

Bridges are commonly posted because of deteriorating condition, damage caused by illegal overloading, or where they were originally designed for lower load limits than current General Access limits.  Bridge postings can be applied for short periods to enable repairs or strengthening to be completed, or for long periods of time where the bridge still meets the current needs of the network. 

A list of Waka Kotahi posted bridges can be found further down this page. This list is reviewed in October each year, though additional postings may be added during the year as required.

Posted bridge restrictions are legally enforceable limits covered by regulation 11(external link) of the Heavy Motor Vehicle Regulations 1974.

Speed restrictions

Speed restrictions are the most common form of restriction. Lowering the speed of travel reduces the dynamic effects of the vehicle on the bridge as it crosses. Some bridges require restrictions on both speed and weight.

Where road users exceed the bridge speed and weight limits, they cause damage to the structure and also put themselves and others at risk. This can lead to the closure of a bridge to keep all road users safe.

Changes to the way bridges postings are presented

Waka Kotahi NZ Transport Agency is changing the way bridge restrictions are presented. This is to make them more easily understood.

Until recently, bridge restrictions may include one or more of the following;

• Speed of travel over a bridge
• Individual axle weights
• Gross mass of the vehicle, expressed as a percentage of the Class 1 limits.

Road users have often found it difficult to understand the “gross mass limit”. To determine their vehicles mass limits users needed to look up the axle set and gross mass limits within the Vehicle Dimensions and Mass Rule.

The new method of presenting this information will enable road users to quickly understand their maximum load limits. Under the new approach, bridges can be posted with

• Speed of travel over a bridge
• Individual axle and axle set weight limits
• Gross mass limits, which vary depending on how many axles a vehicle has.

The table below provides an example of the different limits for a typical posted bridge.

Under the previous approach, the posting included in the table above would have been presented as '50% of Class 1, 50km/hr'.

Bridge posting limits will vary depending on the reason for the restriction. Some bridges will require only speed restrictions, whereas others may also require restrictions on axle masses or the gross mass of the vehicle.

In time, all postings on the state highway and local road networks will be changed to this new approach.

Notification of weight and/or speed limits on state highway bridges 2021-22

Waka Kotahi has fixed the following maximum weight and/or speed limits for heavy motor vehicles and combinations that include a heavy motor vehicle on the bridges below (bold restrictions indicate changes made since October 2020):

The following bridges have further restrictions in place in accordance with New Zealand Transport Agency (Traffic Controls on State Highways) Bylaw 2017/14:

Related information

Bridges and structures