delivered the opinion of the court.
Defendant below appeals from a judgment awarding plaintiff damages for injury sustained by reason of defendant’s negligence.
The evidence summarized shows that as plaintiff drove his truck with house trailer at a speed of 35 to 40 miles per hour across a bridge some six feet less in width than the oiled surface of the road on either end of the bridge, appellant, driving his pickup truck at 65 miles per hour, attempted to pass plaintiff’s vehicle, and in so doing the pickup truck struck the left rear of the trailer house causing damage to both the trailer house and its contents. As the value of plaintiff’s loss was stipulated, appellant’s only complaint is that the court erred in finding for plaintiff, because (1) there was no evidence that appellant’s failure to sound his horn was the sole proximate cause of the accident, (2) the evidence clearly proves the trailer house crossed the center line in appellant’s lane of travel, and (3) appellee failed to determine he could safely cross the center line before so doing.
*580To sustain his position regarding' the movement of the two vehicles immediately before and at the time and point of impact, appellant relies principally upon the opinion identification by a patrolman that certain tire markings on the road were made by the two vehicles involved, and his opinion identification as to which such markings were made by a particular vehicle. This usurped the province of the trier of fact, and, even though not objected to, still left the determination of those facts for decision of the trier of fact. Again appellant misinterprets an opinion expressed by the officer as saying that the impact caused appellant’s car to slide “at an angle from its original direction” when the officer merely said that a vehicle sliding would leave broader tire marks. Even though we might agree that the assumption is correct, it nevertheless was the province of the trier of fact to gain that inference. It was not a matter for the opinion of an observer after the fact, irrespective of whether such person was an officer or a layman, unless by foundation the witness - was shown to have in fact witnessed the same or similar or comparable kind of impact, and thus possessed a peculiar knowledge not possessed by the trier of fact.
While this facet of the case fades in significance inasmuch as the trial court seemingly attached little if any importance to it, it may be of service to note that no proper foundation was laid showing the special qualification of the witness to express an opinion. The mere fact that a patrolman investigates many highway ac* cidents does not of itself qualify him as an expert to determine how accidents he has never seen occurred.
Appellant seems to concede, and we think the evidence shows, the appellant did not sound his horn, yet 'appellant asserts there is no evidence that his failure to sound his horn was the sole proximate cause of the accident. Of course, there could be liability if that failure was a proximate cause sans contributory negligence of plaintiff. Notwithstanding, as supporting this contention, appellant cites § 31-101 (b), W.S.1957. This statute only requires the driver of an overtaken vehicle to give way to the right in favor of the overtaking vehicle on audible signal. Appellant’s added criticism of appellee’s driving speed of 30 to 35 miles per hour (in reality 35 to 40 miles per hour), and the characterizing of appellant’s speed of 65 miles per hour as “normal” traffic speed, is not only without merit but is completely unsound. Thirty-five or forty miles an hour, the speed which is shown by the evidence, is not such an excessively slow speed as to unduly impede the flow of traffic, especially when the nature of the vehicle and its load does not reasonably admit of higher speeds. This is true whether the vehicle be a truck-trailer-house combination or an excessively heavy vehicle which is lawfully permitted on our highways. We have already decided that a speed of 20 miles per hour is not negligent as a matter of law. Dallason v. Buckmeier, 74 Wyo. 125, 133, 284 P.2d 386, 389. Neither can it be said that 65 miles per hour is the normal traffic flow. On our two-lane highways, 65 miles per hour is the maximum speed deemed prima facie reasonable. That does not imply that all motor-vehicle travel shall or normally does proceed at that maximum speed or that driving at a less speed must be considered as driving improperly.
We have carefully examined both the transcript of testimony, the freehand sketch purporting to show the accident scene, and the photographs taken after the accident. The testimony relative to what are said to be skid marks appearing on the exhibits is so unclear as to be almost meaningless. There seems, however, to be no question but that the appellee had complete control of his vehicles, and even appellant admits that is so. There was a high wind blowing at the rate of as much *581as 54 miles per hour; the appellee’s trailer was 8 feet wide by 24 feet long, a rather large box-like affair; it came onto the portion of the roadway which narrowed some six feet at the bridge while it was to the right of the center line; and while still upon the far end of the bridge the trailer was struck by appellant’s automobile which at the time seems to have admittedly been skidding. We find no "clear” evidence that the trailer crossed into ap-pellee’s passing lane prior to the collision. Even had this been the case, Dallason -v. Buckmeier, supra, indicates he might have lawfully done so without being negligent if he had a clear view and had no warning of a vehicle approaching from behind.
There is no evidence that appellee failed to determine he could cross the center line with safety nor was such a determination necessarily relevant inasmuch as the trier of fact could have found under the evidence that the appellee did not cross that line before his trailer was struck.
The finding and judgment of the district court is justified and supported by the evidence, and we find no error adverse to appellant. The judgment is affirmed.
Affirmed.