Is a failure to sound a horn conclusive of liability?

That the failure to sound a horn is not conclusive of liability was made clear in the case of The King v. Anderson, 1946 CanLII 20 (SCC), [1946] S.C.R. 129 where Estey J. stated at p. 134: What is “reasonably necessary” is a question of fact upon which point the learned trial judge in this case has made no finding. While I do not minimize the importance of sounding a horn under other circumstances, the evidence in this case, having regard to the width of the street, the absence of other traffic, the conduct of the respective drivers and the doubt as to their east-west position on Georgia street, does not establish a case of reasonable necessity therefor and consequently does not warrant a finding of negligence on the part of the respondent taxi driver.