A general rule of Canadian law is that hearsay evidence is not admissible in court.
Hearsay evidence is an oral or written statement that was made by someone other than the person testifying in court.
Hearsay evidence occurs when the statement or evidence happened outside of the court and a witness testifying in court attempts to repeat the evident to enter the evidence before the court.
As a general rule hearsay evidence is not admissible in a speeding ticket trial.
A driver cannot say what someone else told them, that person must come to court to testify.
E.g. The driver could not say that their passenger told them that they saw the speed limit sign on the street and as a result of that information they drove at the stated speed.