Prior loss of steering control?
11 The appellant submitted that, if a motor vehicle was not involved and the respondent did not alter his steering direction, the more probable explanation for the respondent going into the potholes was that the final fracture of the head stem occurred as the respondent was following his safe course along the roadway, thus steering control was lost, and going into the potholes and all that followed was due to the prior loss of steering control. If so, it said, the accident was not attributable to any negligence on its part.
12 Could the final fracture have occurred as the respondent was following his safe course along the roadway? Quorrobolong Road was not a smooth road, and the respondent was riding fast at about 25 miles per hour. Both Dr Thompson, a metallurgist called for the respondent, and Mr Robinson, a metallurgist called for the Nominal Defendant, said that the final overload fracture could have been caused by the loads generated by encountering potholes, but that it could also have been caused by the loads arising from normal riding on the roadway. Mr Robinson said, for example, that the final overload fracture could have been caused by a light impact such as running over a small rock or a branch on the surface of the roadway. Dr Thompson expressed a view, based on sub-critical fractures visible on microscopic examination of the head stem tube, that the sub-critical overloads probably occurred at a similar time to the final overload fracture, which the respondent said was consistent with rapid sequential loads from encountering potholes. Dr Thompson's evidence, however, did not rise above consistency, and could not do so. The Master accepted the evidence of Dr Thompson and Mr Robinson. In my view this included acceptance that the final overload fracture could have been caused by the loads arising from normal riding on the roadway,
13 If the respondent's account of the involvement of a motor vehicle is not accepted, therefore, the final overload fracture and loss of steering control could have been before the respondent went into the potholes, with going into the potholes and all that followed being due to the prior loss of steering control. It was necessary for the respondent to establish, on the balance of probabilities, that the final overload fracture and loss of steering control was after and because the respondent went into the potholes. Only if that were more probable than not could the accident be attributable to any negligence on the appellant's part.
14 The respondent accepted in the appeal that he could not properly contend that the roadway where he normally followed his safe course was potholed or otherwise so rough as to connote negligence on the appellant's part: hence the importance of the divergence from the safe course into the potholes. He submitted that the Master was entitled to infer that he diverged into the potholes due to lapse in concentration, rather than because of prior loss of steering control. Although his evidence was to be examined with caution, it was said, the respondent was accepted so far as there was an issue over whether he was riding away from Cessnock or towards Cessnock at the time of the accident; there was ample evidence from local residents of potholes and rough edges along Quorrobolong Road, and in particular in the location where the respondent fell from his bicycle; the photographs of the roadway suggested that it was not excessively deteriorated along the safe course; as I have earlier noted; Dr Thompson's evidence in relation to the sub-critical fractures was consistent with rapid sequential loads from encountering potholes; and there was evidence that the respondent had given an account of the accident not involving a motor vehicle in which loss of steering control came only after he went into the potholes. These matters in combination, it was said, sufficed to uphold the Master's conclusion, and with it the probability that loss of steering control was after and because the respondent went into the potholes.
15 To further explain the evidence of the respondent's account last mentioned, Senior Constable Barber said that when he attended the scene of the accident the respondent told him that he (the respondent) was travelling along the road as he always did "when he hit a couple of potholes and the handlebars of the push bike came away and he hit a tree". The Master did not make a direct finding as to what the respondent said to Senior Constable Barber, and did not seem to rely on it for her conclusion. That the respondent said this was not supported by the evidence of others who attended at the scene of the accident. The weight to be attributed to the evidence is negligible, particularly when it stands alone and on the respondent's case must be taken as a truncated version of the account of the accident given by the respondent in his own evidence, with the involvement of the motor vehicle in forcing the respondent into the potholes.
16 I am not persuaded by the respondent's submission, and do not think that the Master's conclusion can stand. Adopting what was said in Holloway v McFeeters (1956) 94 CLR 470 at 480, the circumstances appearing in evidence do not raise a more probable inference in favour of the final overload fracture and loss of steering control being after and because the respondent went into the potholes, and do no more than give rise to conflicting inferences of equal degrees of probability so that the choice between them is a mere matter of conjecture. The respondent was a highly experienced cyclist, used to riding on Quorrobolong Road at speed and keeping about two feet in from the left hand side of the sealed roadway. Intentional or unintentional divergence into the potholes, which he considered presented a danger, is not likely. In my view the more probable explanation of the accident is that the final overload fracture of the head stem occurred whilst the respondent was riding normally along the roadway, and that his bicycle then diverged into the potholes and there followed his fall from the bicycle.
17 Since writing the foregoing I have had the benefit of reading the further observations of Rolfe AJA in draft. My reasoning is in accord with that of his Honour, and I adopt what he has said.