Limitations of inferential reasoning considered in determining whether there was negligence of the driver of an unidentified vehicle

20 April 2022

The Victorian Supreme Court has highlighted the limitations of inferential reasoning in relation to a plaintiff’s ability to prove that the oily substance on a highway, that caused her to collide with another vehicle, was on the highway by reason of the negligence of the driver of an unidentified vehicle pursuant to s96 of the Transport Accident Act 1986 (Vic).

In issue

The plaintiff was driving along the Warburton Highway when her vehicle slid on oil or diesel on the surface of the highway, and collided with an oncoming vehicle. The plaintiff was injured and brought proceedings against the Transport Accident Commission seeking damages. Quantum was not in issue nor was the fact that the substance caused the collision. However, no witness gave evidence concerning a particular vehicle from which the substance concerned might have emanated. Therefore the issue for His Honour Justice O’Meara to consider was whether the substance was on the highway by reason of the negligence of the driver of an unidentified vehicle pursuant to section 96 of the Transport Accident Act 1986 (Vic).

The plaintiff’s claim was reliant on inferential reasoning. That is it was not necessary for her to exclude ‘reasonable hypotheses consistent with innocence’, and she need only raise ‘a more probable inference in favour of what is alleged’. His Honour noted, however, there must still be circumstances such as to give rise to one or more ‘reasonable and definite inference[s]’ that the negligence of the driver of the unidentified vehicle was a cause of the presence of the oil or diesel trail on the roadway.

The background

Having regard to the consistency of the oil trail it was accepted that the oil must have been deposited on the roadway by an unidentified vehicle shortly before the accident. Nothing was directly known about the unidentified vehicle in question.

The plaintiff’s counsel emphasised the magnitude of the spillage and its continuous nature, and submitted it was ‘consistent with spillage rather than mechanical failure of a vehicle’ and ‘inferentially from a load’, the spillage was consistent with ‘negligence in the loading and/or supervision of the load’, as there was an ‘absence of explanation’ of an occurrence (namely the oil trail) it was ‘unlikely to occur without negligence on the part of the driver of an unidentified vehicle’ and the vehicle was ‘under the control of the unidentified driver’.

Counsel for the defendant submitted that it was likely the driver of the unidentified vehicle had been ‘totally oblivious’ to any leakage, and there were ‘so many variables that could be at play’ that it was not possible to be satisfied that the oil trail had been deposited on the roadway by reason of the negligence of an unidentified driver.

The decision at trial

Ultimately Justice O’Meara was not satisfied, on the balance of probabilities, the accident occurred as a result of the negligence of the driver of an unidentified vehicle.

In arriving at his determination, Justice O’Meara opined that:

  1. Any vehicle or load may well be the responsibility of and loaded onto the vehicle via processes involving employees, sub-contractors or persons quite distinct from the driver of the vehicle. Further, the leak may well come about as a consequence not of any fault in the vehicle, or even any fault of the person owning, possessing or loading it, but as a consequence of inattention by some entirely different person that filled it with fuel at an earlier and indeterminate time.
  2. The mere fact that any such vehicle or load later springs a leak could not necessarily stand to implicate the driver of the vehicle carrying it. The evidence did not otherwise link the source of the oil trail to any particular property or business; which gives rise to a sequence of further permutations that such vehicle or load had been damaged while in transit and then sprung a leak. Such damage could, conceivably, be inflicted by a rock kicked up from a passing vehicle, but could also be inflicted by a jolt when the vehicle passes over a bump on the country roads concerned.
  3. His Honour rejected the submission that the driver concerned must have failed adequately to supervise his or her load when driving on the morning because a leak sprung from it and remained undetected for some kilometres because, among other things, the leak must have emanated from behind or under the vehicle and the conditions were of dim light and potential rain/spray at the time meaning the driver likely did not see the leak.
  4. In the present context there are many potential scenarios that arise, some with potential negligence of the driver of the unidentified vehicle. However there are many scenarios in which there is either no negligence at all, or negligence of someone else entirely. On the evidence there was no possible basis to determine which one or more of the many scenarios is the more probable.
  5. It was not a case in which nearly all of the scenarios return to a point at which the driver has ‘ultimate responsibility’. The inference invited by the plaintiff must be a ‘more probable inference’. His Honour was not able to be satisfied there was one or more ‘probable inferences’ in favour of what was alleged.
  6. On the evidence the position concerning any negligence in connection with the oil trail was ultimately too speculative, and there were too many potential scenarios consistent with the driver of the unidentified vehicle having no liability in negligence.

Implications for you

  • Claims pursued under section 96 of the Transport Accident Act 1986 (Vic) for damages caused by the negligence of the driver of an unidentified vehicle that involve the emanation of road hazards such as oil or any other object causative of an accident will, at times, rely on inferential reasoning by virtue of the unknown vehicle/driver.
  • In such cases it is not enough for the plaintiff to show that the hazard could have been caused by the negligence of the unidentified driver, or even that it was probable. The plaintiff must show that negligence on the part of the driver of the unidentified vehicle is more probable than any other explanation for the hazard which did not include negligence.
  • Insurers should therefore be alert to claims in which a plaintiff is reliant on inferential reasoning, in circumstances where there could be an array of possible scenarios and the one alleged may be no more probable than a scenario not involving negligence.

Seward v Transport Accident Commission [2022] VSC 137

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