These are actions of tort; the first to recover for personal injuries, the second to recover for personal injuries and for damage to an automobile. The declaration in the first case contained a single count and was in compliance with the statutory form 13, G. L. c. 231, § 147: it alleges that the plaintiff “was lawfully travelling in an automobile ... that while he was so travelling, he received and suffered bodily injuries in consequence of having been struck by one of the defendant’s cars; And the plaintiff says that his said injuries were caused by reason of the carelessness and negligence of the defendant, its agents and servants, in the management, propulsion and control of said car.”
The plaintiff Smith was a police officer in Boston, assigned to traffic duty at the intersection of Commonwealth Avenue and Dartmouth Street. On April 2,1925, there was an accident on Commonwealth Avenue near Exeter Street resulting in injury to a woman. Smith went to the scene of the accident, and, finding there an automobile, owned and driven by the plaintiff Hackett, which had been commandeered by another officer for the purpose of conveying the injured woman to the Boston City Hospital, he stepped upon the left running board. The automobile proceeded down Commonwealth Avenue, turned into Dartmouth Street, approached the intersection of that street and Boylston Street, and, as it was crossing Boylston Street, collided with an outbound car of the defendant, causing injuries to both plaintiffs and damage to the automobile. Although the evidence in connection with the accident was conflicting, the fact of the collision, and that both plaintiffs were injured and the automobile was damaged, were established by the verdict of the jury in each case.
The plaintiff Smith testified, in substance, that there were two impacts between the electric car and the automobile; that the first impact turned up that part of the running board on which his right foot rested and thereby prevented him from releasing it and freeing himself from a dangerous posi*430tian between the car and the automobile, both of which had come to a stop; that it was impossible to move the automobile and in order to release his foot it was necessary to back the car; and that he was not seriously injured by the first impact. There was testimony, however, of witnesses called by the defendant that the expression of his face and an outcry made by him indicated that he was in pain. There was evidence that the motorman was told to back his car but did not do so and instead the car came forward again crushing Smith’s leg and rendering him unconscious.
At the close of the plaintiffs’ cases, the defendant presented in each case the following motion: “And now, at the close of the plaintiff’s evidence, no amendment of the declaration having been allowed, the defendant, not resting, moves that the plaintiff be required to elect whether the cause of action upon which he will rely is the socalled first striking or the socalled second striking or impact, the plaintiff having offered evidence of both sinkings equivocally, leaving the defendant in doubt as to what claim of negligence and damages under the declaration it is called upon to meet.” The presiding judge refused to rule upon the motions at that time, suggesting to the defendant’s counsel that they be presented at the close of all the evidence; to such refusal the defendant excepted.
It was within the power of the judge to allow amendments even by adding further counts at any time before final judgment. G. L. c. 231, § 51. Pizer v. Hunt, 253 Mass. 321,330, 331. Ripley v. Taft, 253 Mass. 490, 493. His refusal to consider the motions when first presented was not error. At the close of the evidence, the motions were again presented and were denied, subject to the defendant’s exceptions.
It is the contention of the defendant that if there were two impacts, as the plaintiff Smith and other witnesses testified, there were two causes of action, one for each impact, and as the declaration in the first case contained but one count setting forth a single cause of action, and in the second case it being agreed that the two counts of the declaration may be regarded as one, the plaintiffs should have been required to *431elect upon which they intended to rely. We are of opinion that upon the evidence the jury were justified in finding that the two impacts were so connected as to constitute a single cause of action. They could have found that the first application of force created a situation of imminent peril necessitating immediate action in order to prevent still more serious consequences to the plaintiffs, and that both impacts constituted a unified whole rather than a disconnected sue-cession of events. The fact that after the first impact the automobile and street car had come to a full stop does not separate all that preceded from that which followed as matter of cause and effect. Hartnett v. Tripp, 231 Mass. 382, 385. It could have been found that no independent force intervened after the first injury to the plaintiffs; that the efforts of the motorman to back the car were the natural, probable and proximate consequence of a dangerous situation resulting from the first impact; and that the act of the motorman causing the second impact, by driving his car forward instead of backing it away from the automobile, was an act of negligence inseparably connected with the first impact, from which additional injury came to the plaintiff Smith; it was a continued injury and not a distinct and independent injury. In principle the two impacts were no more separate and independent transactions than is the commitment of an assault and battery where several blows are struck. Benson v. Swift, 2 Mass. 50. The acts of the motorman causing the injury were connected and constitute a single cause of action. Trask v. Hartford & New Haven Railroad, 2 Allen, 331. Goodrich v. Yale, 8 Allen, 454. Knowlton v. New York & New England Railroad, 147 Mass. 606, 608. Bliss v. New York Central & Hudson River Railroad, 160 Mass. 447, 455. The motions that the plaintiffs be required to elect whether they would rely on the first or second impact could not properly have been granted.
Of the defendant’s first eight requests for rulings the fourth and fifth were given; the others were based upon the theory that the plaintiffs were required to elect and, for reasons previously stated, were rightly denied. At the close of the evidence the defendant moved in each case that a *432verdict be directed in its favor, its contention being that as matter of law the plaintiffs were guilty of contributory negligence, and that there was no evidence of negligence by the defendant’s motorman.
Upon the issue of contributory negligence the burden of proof rested upon the defendant. G. L. c. 231, § 85. At the time of the accident the plaintiffs were conveying an injured woman to a hospital. There was evidence tending to show that as the automobile approached the intersection of streets its speed was reduced to four or five miles an hour; that Smith held up his hand as a signal to the motorman of the outbound car. Smith testified that the car at that time was at a white post at a regular stopping place; that it was stopped and the doors were just closing; that “When he observed the doors closing he had the signal up for that car to stop”; that the view of the motorman was unobstructed and Smith could see him; that after signalling the motorman of the outbound car he turned to signal the motorman of an inbound car which was moving slowly. Other witnesses testified that they saw Smith signal the motorman of the outbound car by waving his hand. It is manifest that the signal of Smith, although he was a police officer, at that time carried no greater authority than the signal of any other individual, and the judge, in substance, so instructed the jury. In view of the fact that the plaintiffs were conveying an injured person to a hospital, and the other evidence, it could not rightly have been ruled that Smith was negligent in riding upon the running board. It was for the jury to determine whether his so riding constituted negligence. Coyne v. Maniatty, 235 Mass. 181, 185, and cases there collected. Terlizzi v. Marsh, 258 Mass. 156. The question whether the plaintiffs were in the exercise of due care was for the jury.
It could not have been ruled that there was no evidence of negligence on the part of the defendant. It could have been found that-the motorman could see the automobile before it reached the intersection of streets; that he could see the signal given to him by Smith before the outbound car started from the white post; that when he first saw the automobile, his car had attained a speed of from eight to ten miles an *433hour; and that he was negligent under the circumstances in starting the car before the automobile had passed over the outbound track. The judge accurately instructed the jury upon the issues of due care and negligence.
The exceptions of the defendant to the refusal to give request 17a and to the alleged failure of the judge to charge adequately on request 17d, must be overruled. Request 17a was rightly denied because upon the evidence offered by the plaintiffs it could not have been ruled that the plaintiffs had violated the provisions of G. L. c. 90, § 24, relating to the operation of motor vehicles. Whether there was such violation was a question of fact for the jury and the judge in effect so ruled. Request 17d was sufficiently and accurately covered by the charge. The instruction that the plaintiffs could have been found to have violated the statute without being negligent was correct. Commonwealth v. Pentz, 247 Mass. 500, 509. Commonwealth v. Vartanian, 251 Mass. 355, 358. Commonwealth v. Gurney, 261 Mass. 309, 312. As the judge in his instructions fully and correctly covered the question of dual control of the automobile by the plaintiffs, the defendant’s exception to the refusal to give the fourteenth request cannot be sustained.
The defendant excepted to that part of the supplementary charge wherein certain interrogatories propounded by the defendant to the plaintiffs and the answers thereto which contained no reference to the second impact are dealt with. We are of opinion that the instructions given upon this issue were not prejudicial to the rights of the defendant.
We have examined all exceptions to the refusal to give requests presented by the defendant. Some were not argued and therefore are treated as waived. Fay v. Hunt, 190 Mass. 378. Others, dealing with particular views of the evidence, were for that reason not improperly refused. Hicks v. New York, New Haven & Hartford Railroad, 164 Mass. 424, 428. Quinn v. Standard Oil Co. of New York, 249 Mass. 194, 204. Coates v. Bates, 265 Mass. 444, 448. The contention that the cause of Smith’s injuries was conjectural is without merit. Toy v. Mackintosh, 222 Mass. 430, cited by the defendant, can have no application in view of the undisputed *434evidence in the case at bar that Smith was conscious following the first impact.
We find no reversible error in the denial of the requests; nor can the exceptions to parts of the charge be sustained.
It would serve no useful purpose to discuss them in further detail.
Exceptions in each case overruled.