With Road User Charges (RUC) applying to Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) from 1 April 2024, it is useful to consider why we have a RUC system in New Zealand.

The Ministry of Transport has a very useful document on its website to explain the system (RUC-CAM document). The TL;DR version is here:

• The road user charges (RUC) system in New Zealand is a way of charging vehicles for using the roads based on how much they travel and how much they damage the roads.
• The RUC system was introduced in 1977 and has been reviewed and updated several times. It is considered world-leading and many other countries are interested in learning from it.
• The RUC system has two main goals: to recover costs from vehicles that use the roads, and to reflect the costs that different vehicles cause to the roads.
• The RUC system uses a cost allocation model (CAM) to calculate the RUC rates for different types of vehicles. The CAM is based on engineering principles and expert judgments, and it divides the costs into five categories: pavement wear, space, weight, policing, and common costs.
• The RUC rates vary depending on the vehicle’s weight, size, axle configuration, and fuel type. Light RUC vehicles (up to 3.5 tonnes) pay the same rate, while heavy RUC vehicles (over 3.5 tonnes) pay different rates based on their features.
• The most important factor for determining the RUC rates for heavy vehicles is the pavement wear that they cause, which is calculated using the fourth power rule. This rule says that the damage to the road increases exponentially with the weight of the vehicle. However, this rule may not be valid for all roads in New Zealand, and it could be improved in the future with more data and technology.

The implementation of RUC for EVs and PHEVs is the first stage towards the introduction of RUC on all vehicles. The Ministry of Transport is expecting to develop policy proposals for this work over 2024-2025.