The exceptions are to the refusal to give the two instructions requested. The first instruction requested was given substantially with the modification, that, if, the post was an obstruction in the carriageway, or was so near to the carriageway as to make travelling on it unsafe, then it was a defect; and this, we think, is a correct statement of the law. In the present case the carriageway was narrower than in Macomber v. Taunton, 100 Mass. 255, but this is the principal difference between the two cases. The narrowness of the part of the way wrought for carriage travel might have some bearing upon the question whether the post was so near to it as' to make the carriageway unsafe, but if the post did not, under the circumstances, constitute a defect in the way intended for carriage travel, the plaintiff cannot recover.
The exceptions state that the ordinances had been duly passed, and that the penalties attached to them were lawful. Woodward had, therefore, no right to drive his wagon upon the sidewalk. If he intentionally and unnecessarily had driven it on the sidewalk, and this was a contributing cause of the injury, the plaintiff could not recover, because the defendant is not *602liable if the unlawful or negligent act of a third person contributed to the injury. Rowell v. Lowell, 7 Gray, 100. Shepherd v. Chelsea, 4 Allen, 113. Tuttle v. Lawrence, 119 Mass. 276. Newcomb v. Boston Protective Department, 146 Mass. 596.
The second request assumes that the travelled part of the way was not of sufficient width to allow the safe passage of Woodward’s wagon by that of Dow, while the evidence did not support the assumption, if the words are taken literally. The request was material only in case the jury should find that the post rendered the part of the way wrought for carriage travel unsafe. Undoubtedly, a person driving in a wagon on a dark night, and attempting to pass another wagon driven in the same direction, is more likely to go beyond the limits of the travelled way if it is only sixteen and a half feet wide, than if it is twice that width; still, a traveller cannot justify driving upon a sidewalk in violation of an ordinance, merely because it is convenient in order to pass at a particular place a wagon that is driven before him. If any necessity would justify violating an ordinance of this kind, mere convenience would not. Commonwealth v. Adams, 114 Mass. 323.
Without considering whether an unintentional violation of the ordinance, if it contributed to the injury, would necessarily defeat the action, we think that evidence that Woodward, without being able to distinguish where the line of the sidewalk was, voluntarily undertook to drive by the wagon of Dow on a narrow street, the width of which the jury must have found was known to him, had some tendency to show negligence on his part. The attempt to drive by, under the circumstances proved, may have seemed to the jury careless.
Exceptions overruled.