Vehicle Inspections

ACRS Policy Position

Vehicle defects are not a major cause of road crashes, nor even a significant contributor along with other causal factors.   Where defects do make a contribution, the most common cause is defective or underinflated tyres.

Where compulsory periodic vehicle inspections are already applied and it is desired by the authority concerned to maintain them, they are a valid means of helping to maintain vehicle roadworthiness.

However compulsory systems are not completely effective in this role and a well designed and executed alternative such as a random inspection system can be just as effective.

Given that 'the jury is still out', a good compromise may be an on-road system combined with inspection of a randomly chosen small sample (say 5%) of all motor vehicles over five years old.

Finally, maintaining a safe and roadworthy vehicle is the responsibility of the vehicle owner. 

Objective

To help maintain the fleet in a safe and roadworthy condition

Discussion

Some jurisdictions adopt compulsory periodic vehicle inspection as a means of maintaining roadworthiness of vehicles in use.   In recent times those jurisdictions that have compulsory inspection have modified schemes to, for example, reduce the requirement for inspection in the early years of the vehicle's life.   There are two reasons for doing this: a perception that few vehicles have major wear and tear defects early in their life, and to reduce the administrative cost of the system.

Jurisdictions that have compulsory inspection have either government testing stations or licensed, authorised private facilities to carry out inspections and issue certificates of roadworthiness.

Other jurisdictions deal with roadworthiness by various means, such as requiring a certificate of roadworthiness on change of ownership or first registration in the jurisdiction.   All jurisdictions supplement their schemes by authorising police and enforcement agencies to issue defect notices where necessary and appropriate.

There are supporters and opponents of both arrangements.   It is generally agreed that to set up a system of compulsory inspection from scratch would be extremely costly and unlikely to be beneficial.   There is less agreement on compulsory schemes already in place; there is considerable resistance to abolishing them or curtailing their operations, on the grounds of public perception of reduced safety monitoring.

Compulsory systems are costly to run and there are recurrent pressures to contract out or find less administratively expensive ways of achieving the same objective.   Therefore, several jurisdictions contract out periodic inspections to avoid the cost of operating inspection facilities. 

Any inspection system must demonstrate two things to be considered effective:   firstly that defects contribute to crashes and road trauma, and secondly that having an inspection scheme reduces the incidence of vehicle defects that contribute to crashes.

At present there is no clear answer on whether compulsory systems have a better result in terms of reducing unroadworthy vehicles, than other systems.   Crash data analysis generally finds that vehicle defects have a very minor part to play [4-7%] in direct crash causation (McLean et al) and not much more in part contribution (along with other factors) to the crash [10-15%].   By far the most frequently found defect is in tyres:   worn, damaged or under-inflated.

This illustrates one of the problems of compulsory inspection systems:   a vehicle may pass inspection but shortly be unroadworthy because of continuing deterioration.   Tyre replacement, and hence the potential for defect, occurs many times during a vehicle's life.   There is no guarantee that a vehicle subject to annual inspection will remain roadworthy for the intervening year. 

It has been argued that a system of random inspections by enforcement officials can do at least as good a job in maintaining roadworthiness of the fleet as periodic inspection.   Seeing a defect such as a tyre worn beyond legal limits could trigger an official demand that the problem be rectified and that the vehicle be subject to a comprehensive roadworthiness inspection within a specified but short period of time.   This work could be done by police and by officials such as parking inspectors.

The very unpredictability of this approach may serve to raise the incentive for vehicle owners to maintain at least a minimum standard of roadworthiness, in much the same way as random breath testing is a disincentive to drinking and driving.

On-road inspection systems when properly designed could be more effective than regular compulsory inspections.   However, this would only be the case if such systems are perceived to provide a relatively high level and frequency of inspection, and thus deterrence.

A good compromise may be an on-road system combined with registration-linked inspection of a randomly-chosen small sample (say 5%) of all vehicles over five years old.

These considerations highlight the core issue:   that vehicle roadworthiness is a continuing responsibility of the vehicle owner.   If, as the evidence suggests, most defects that are implicated in crashes are readily easily identifiable and corrected, there may be need for public education measures to encourage vehicle owners to be vigilant and take the necessary safety steps in their own interest.

Reference

Mclean AJ, Aust HS, Brewer ND and Sandow BL (1979) Adelaide in-depth accident study 1975-79 Part 6, Car Accidents, University of Adelaide