Following a trial by jury the appellant, William B. Mahaney, was found guilty of driving under the influence in violation of 75 Pa.C.S. § 3731(a)(1). Post-verdict motions were denied and a forty eight (48) hour to twenty three (23) month sentence was imposed. Appellant appeals from this judgment of sentence. We affirm.
On January 4, 1986 Officer Theodore McGinley received a call at 1:56 a.m. reporting an accident with injuries on West Ridge Pike, Limerick Township, Montgomery County, Pennsylvania. He arrived at the scene about a minute later. Appellant was standing with two state troopers, both of whom left after McGinley arrived. Their identity is unknown. There were no witnesses to the single car accident.
McGinley testified that appellant's speech was slurred, that he smelled of alcohol and was obviously off balance. Appellant admitted he had been drinking.
At 2:30 a.m. appellant was taken by ambulance to Sacred Heart Hospital for treatment of a cut over his right eye. McGinley remained at the scene to investigate the accident.
Sometime after midnight but before the accident, McGinley had observed a saw-horse barricade with flashing lights five to six feet off the road in the grass. After the accident he found this barricade, along with other debris, in the middle of the road. McGinley found skid marks leading off the road to the right, twenty feet west of the intersection of Ridge and Country Club Road. There were also skid marks *132through the place where the barricade had been, across Country Club Road, through a mailbox, across four traffic-lanes to the other side and into two cut-off telephone poles which were in the dirt. There was a trail of mud from the two poles back across Ridge Pike onto the premises at 165 West Ridge Pike. The road was otherwise dry.
Shortly before 4:00 a.m. Officer McGinley arrived at the hospital, arrested appellant for driving under the influence and obtained permission to test appellant’s blood for alcohol. Appellant submitted to the blood test in McGinley’s presence and the sample was taken to the police station by McGinley. Dr. Paul Schweda, Director of National Medical Services tested the sample and found the blood alcohol concentration to be .17 percent by weight.
According to appellant’s version of the facts he became intoxicated after the accident. While appellant was not sure of the exact time of the accident he assumed it to be around midnight. He was driving east on Ridge Pike when something crashed through his windshield causing him to lose control of his car. (It was later determined that it was the flashing sawhorse barricade). After the accident appellant moved the badly damaged car into a nearby parking lot to inspect it. He attempted to change a tire but did not have a lug wrench. He then walked to a friend’s house where he met Bruce Waters. Appellant and Waters left the house with a six-pack of beer. Waters took one beer and left to search for a tow truck. Appellant returned to the car and drank the other five beers over the next hour while waiting for Waters to return. In the meantime, Officer McGinley arrived on the scene. At trial, appellant admitted drinking the five beers and having two glasses of scotch with dinner, earlier in the evening. Appellant denied being under the influence at the time of the accident.
Appellant was found guilty of driving under the influence of alcohol. In this appeal appellant raises the following issues:
I. DID THE COURT BELOW ERR IN FAILING TO GRANT DEFENDANT’S MOTION FOR A DIRECT*133ED VERDICT BECAUSE THE COMMONWEALTH FAILED TO PROVE THE CRIME OF OPERATING A MOTOR VEHICLE UNDER THE INFLUENCE OF ALCOHOL AS A MATTER OF LAW? 1
II. DID THE COURT BELOW ERR IN ALLOWING THE TESTIMONY OF AN EXPERT WITNESS WITH RESPECT TO BLOOD TEST RESULTS WHEN THE COMMONWEALTH FAILED TO PRODUCE THE MEDICAL TECHNICIAN WHO TOOK THE BLOOD TEST OR ESTABLISH THE CREDENTIALS OF THE TECHNICIAN BY INDEPENDENT EVIDENCE?
III. DID THE COURT BELOW ERR IN ALLOWING THE MEDICAL EXPERT TO TESTIFY ON THE ISSUE OF BLOOD TESTING WHEN NO PROPER FOUNDATION WAS LAID TO CONNECT THE TEST RESULTS TO THE TIME OF THE ACCIDENT?
Issues I and II both turn upon appellant’s contention that the Commonwealth failed to establish the time of the accident and thus failed to establish the elements of the crime. Therefore, we will discuss the two issues together. Appellant was convicted of Driving Under the Influence of Alcohol, 75 Pa.C.S. § 3731(a)(1) which provides:
§ 3731. Driving under the influence of alcohol or controlled substance
(a) Offenses defined. — A person shall not drive, operate or be in actual physical control of the movement of any vehicle while:
(1) under the influence of alcohol to a degree which renders the person incapable of safe driving.
75 Pa.C.S. § 3731(a)(1). Thus, the Commonwealth must show the defendant to be (1) the operator of a motor vehicle when (2) under the influence of alcohol to the degree which renders him incapable of safe driving. Commonwealth v. Slout, 288 Pa.Super. 471, 432 A.2d 609 (1981). Appellant’s *134motion for a new trial and/or in arrest of judgment raised the issue of whether there was sufficient evidence to find appellant guilty of driving under the influence of alcohol, 75 Pa.C.S. § 3731.
An appellate court, in evaluating the sufficiency of the evidence, must determine whether, reviewing the entire record in the light most favorable to the Commonwealth as verdict winner and making all reasonable inferences in its favor, there was sufficient evidence to find every element of the crime beyond a reasonable doubt. Commonwealth v. Stoyko, 504 Pa. 455, 462, 475 A.2d 714, 718, cert. denied, 469 U.S. 963, 105 S.Ct. 361, 83 L.Ed.2d 297 (1984).
Circumstantial evidence alone can be sufficient to convict a defendant of a crime. Commonwealth v. Lovette, 498 Pa. 665, 450 A.2d 975 (1982), cert. denied, 459 U.S. 1178, 103 S.Ct. 830, 74 L.Ed.2d 1025 (1983). However, the constitutional requirements of proving guilt beyond a reasonable doubt must still be met. Commonwealth v. Scudder, 490 Pa. 415, 416 A.2d 1003 (1980).
As to whether the Commonwealth presented sufficient evidence to sustain the conviction, we recognize that in finding appellant guilty of (1) operating a motor vehicle, (2) while under the influence of alcohol, 75 Pa.C.S. § 3731; Commonwealth v. Arizini, 277 Pa.Super. 27, 419 A.2d 643 (1980), it was within the province of the jury to believe “all, part, or none of the evidence.” Commonwealth v. Jackson, 336 Pa.Super. 609, 486 A.2d 431 (1984). Appellant cites the case of Commonwealth v. Lavery, 35 Pa.D. & C.3d 333 (1985) to support his contention that in the absence of evidence of the time at which an auto accident occurred, evidence that a defendant was operating the motor vehicle at the time of the accident and that he was legally drunk at the time of investigation does not establish a prima facie case of driving while intoxicated. After a thorough review of the trial record, the briefs and the trial court opinion, we agree with the trial court that in this case, contrary to Lavery, there was sufficient evidence from which a jury *135could infer the time of the accident, which is the only point at which appellant’s physical condition is relevant.
Here, we first have Officer McGinley’s observations upon arrival at the scene of the accident at 1:56 a.m. that appellant was visibly intoxicated as evidenced by appellant’s slurred speech, lack of balance, and odor of alcohol. Appellant admitted at this time that he had been drinking. Also, there was expert medical testimony consistent with a jury finding that appellant could have been under the influence of alcohol as early as 12:00 midnight. Next, the mere occurrence of appellant’s accident could be used to draw the inference that appellant was driving under the influence of alcohol. Commonwealth v. Fairley, 298 Pa.Super. 236, 245, 444 A.2d 748, 752 (1982). This was a one car accident. Appellant lost control of his vehicle under dry road conditions, hit a barricade that had been observed after midnight by Officer McGinley 6-8 feet off the side of the road, then skidded extensively across a four lane highway.
The record evidences two additional factors which we view as significant. One, the accident occurred on a routinely patrolled major roadway. Two, a large quantity of debris, including a large saw-horse barricade remained in the middle of the road when Officer McGinley arrived. Taken together these factors strongly suggest that the accident had just happened. This type of debris presented a major safety hazard and the frequent patrols would have already removed it if significant time had elapsed. The physical evidence present at the scene coupled with Officer McGinley’s observations of appellant’s intoxication at that time were strong indications that appellant was driving under the influence of alcohol when the accident occurred.
Finally, since the jurors were aware of appellant’s contention that he drank the alcohol after the accident because he was in pain and was worried, they were required to decide whether appellant’s testimony was credible. Id. “It is a basic tenet of our system of jurisprudence that issues of credibility are properly left to the trier of fact for resolution.” Commonwealth v. Arms, 489 Pa. 35, 39, 413 *136A.2d 684, 686 (1980) (citations omitted). Here, the jury chose to discredit appellant’s testimony as to when he first became intoxicated. This is a finding of credibility with which we as an appellate court will not tamper. Id.
Viewing the evidence in the light most favorable to the Commonwealth and drawing all such logical inferences therefrom, we conclude that the evidence is sufficient to support a finding of guilt on the charge of driving under the influence of alcohol.
Appellant’s remaining contention is that the trial court erred in allowing testimony concerning the blood alcohol test because the Commonwealth failed to establish the credentials of the technician who drew the blood and failed to produce the technician.
We have reviewed the trial court’s discussion of this issue and agree that 75 Pa.C.S. § 1547(c) and 28 Pa. Code § 5.24 and § 5.1 focus on the qualifications of the person performing the blood testing and the equipment used, not the technician who drew the blood. The qualifications of Dr. Schweda who performed the test and the suitability of the equipment he used were established at trial. (N.T. 10/1/86, at 36, 37, 39, 41, 42). The technician was qualified for his position by the hospital and withdrew the blood under police supervision. Under these facts, the only reason to call the technician who drew the blood would be to establish the chain of custody. However, as the trial court pointed out, when the police observe the technician drawing the blood, the Commonwealth is not compelled to call the technician. Commonwealth v. Arizini, 277 Pa.Super. at 40 n. 4, 419 A.2d at 650 n. 4 (1980). In this case Officer McGinley personally witnessed the technician’s drawing the blood and took immediate possession of the labeled blood. Therefore, there is no chain of custody problem here which would have necessitated the testimony of the technician.
Because we agree that sufficient evidence was presented for the jury to reach its decision that appellant was driving *137under the influence and that the inferences drawn follow directly from the facts presented, we affirm.
Judgment of sentence affirmed.
CIRILLO, President Judge, files a dissenting opinion.. The issue before this Court is whether the court erred in denying Appellant’s post-verdict motion in arrest of judgment.