Plaintiff appeals from the trial court’s order denying her motion for new trial.
On May 28, 1978, plaintiffs decedent was killed when his car left the paved portion of the highway, ran through a ditch, and collided with a tree near the shoulder of the road. There was evidence that decedent had been drinking. The road was in defendant’s jurisdiction. Plaintiff brought this action which came to trial before a jury. At the close of plaintiffs proofs, the trial court denied defendant’s motion for directed verdict. The action went to the jury on the theories of negligence and intentional nuisance. The jury found no negligence on the part of defendant, 100% negligence on the part of decedent, intentional nuisance which was not a proximate cause of the accident, and no damages. Plaintiffs subsequent motion for new trial was denied.
*589Plaintiff raises five claims of error on appeal. Defendant has also cross-appealed.
First, the plaintiff contends that the trial court improperly instructed the jury as to proximate cause. At one point, the court told the jury that it must determine whether the negligence of plaintiff’s decedent was "the proximate cause” of the accident and that "what you have to do in all cases is to determine the proximate cause of the accident”. (Emphasis supplied.) Yet, at other times the court instructed the jury that they must determine whether the negligence of the plaintiff and defendant, if any, is "a” proximate cause.
The plaintiff timely objected to the proximate cause instructions. See GCR 1963, 516.2. The correct instruction is "a proximate cause”. Kirby v Larson, 400 Mich 585, 605; 256 NW2d 400 (1977) (opinion of Williams, J.). Moreover, where the trial court gives contradictory instructions, as in this case, we must reverse on the theory that the jury believed the erroneous instruction. Kirby v Larson, supra, p 607. Thus, the trial court committed reversible error.
Second, plaintiff argues that the trial court erred in instructing the jury that a violation of a particular statute by the defendant is a "prima facie” case of negligence. Plaintiff asserts that the trial court should have told the jury that a violation of a statute creates a "rebuttable presumption” of negligence. Plaintiff timely objected to the "prima facie” instruction.
In Zeni v Anderson, 397 Mich 117; 243 NW2d 270 (1976), the Supreme Court adopted the rule that the violation of a penal statute creates a "prima facie” case of negligence or, alternatively, a "presumption” of negligence which may be rebutted by a showing on the part of the party *590violating the statute of an adequate excuse. The Court used both "prima facie” case and "rebuttable presumption” to label the rule it adopted. Plaintiff argues that there is a difference and that the Court really meant that violation of the statute gives rise to a rebuttable presumption.
Zeni, however, is inapposite. That case and the rule announced therein apply only to the violation of a penal statute. See Zeni, supra, p 143; Baumann v Potts, 82 Mich App 225, 229; 266 NW2d 766 (1978). In the present case, the plaintiff tried to prove that defendant violated MCL 691.1402; MSA 3.996(102) and MCL 224.21; MSA 9.121. The statutes provide in pertinent part:
"Each governmental agency having jurisdiction over any highway shall maintain the highway in reasonable repair so that it is reasonably safe and convenient for public travel. Any person sustaining bodily injury or damage to his property by reason of failure of any governmental agency to keep any highway under its jurisdiction in reasonable repair, and in condition reasonably safe and fit for travel, may recover the damages suffered by him from such governmental agency.” MCL 691.1402; MSA 3.996(102).
<<* * * it is hereby made the duty of the counties to keep in reasonable repair, so that they shall be reasonably safe and convenient for public travel, all county roads, bridges and culverts that are within their jurisdiction and under their care and control and which are open to public travel. The provisions of law respecting the liability of townships, cities, villages and corporations for dámages for injuries resulting from a failure in the performance of the same duty respecting roads under their control, shall apply to counties adopting such county road system.” MCL 224.21; MSA 9.121.
The above are not penal statutes. They impose no criminal liability. Instead, they specifically impose civil liability for breach of the duties imposed *591therein. Violation of these statutes, far from creating a prima facie case or rebuttable presumption of negligence, conclusively establish negligence. In order to violate the statutes the governmental unit must breach its duty to keep the roads in "reasonable repair”. Such a breach would be negligence.
Because a violation of the statutes is negligence as such, the trial court erred in instructing the jury that if the defendant violated either statute it "was prima facie negligent”. That instruction made it more difficult for plaintiff to establish defendant’s negligence. Thus, the instruction prejudiced plaintiff and requires reversal.
Third, plaintiff maintains that the trial court erred in ruling that, as a matter of law, the defendant did not have a duty to remove the tree near the shoulder of the roadway, thus taking this issue away from the jury.
The liability of a governmental unit, including a county, for injuries upon the highway is purely statutory. Goodrich v County of Kalamazoo, 304 Mich 442, 445; 8 NW2d 130 (1943). The applicable statutes are MCL 691.1402; MSA 3.996(102), and MCL 224.21; MSA 9.121, set forth above. The former statute, however, imposes an important limitation on the liability of the state and the county road commission:
"The duty of the state and the county road commissions to repair and maintain highways, and the liability therefor, shall extend only to the improved portion of the highway designed for vehicular travel and shall not include sidewalks, crosswalks or any other installation outside of the improved portion of the highway designed for vehicular travel.”
Thus, the duty of the state and county road commissions is "to keep the 'improved portion of the *592highway designed for vehicular travel’ in 'reasonable repair, and in condition reasonably safe and fit for travel’ Mullins v Wayne County, 16 Mich App 365, 373, fn 3; 168 NW2d 246 (1969), lv den 382 Mich 791 (1969).
It is well settled that the statutory duty is not restricted to maintenance of the paved area of the road. Thus, this Court has held that the state has a duty to properly maintain a guardrail, Hall v Dep’t of State Highways, 109 Mich App 592; 311 NW2d 813 (1981), lv den 413 Mich 942 (1982); Van Liere v State Highway Dep’t, 59 Mich App 133; 229 NW2d 369 (1975); Detroit Bank & Trust Co v Dep’t of State Highways, 55 Mich App 131; 222 NW2d 59 (1974), as well as the shoulder of the road, Johnson v Michigan, 32 Mich App 37; 188 NW2d 33 (1971), lv den 385 Mich 762 (1971). See, also, Lynes v St Joseph County Road Comm, 29 Mich App 51; 185 NW2d 111 (1979) (stop sign); Miller v Oakland County Road Comm, 43 Mich App 215; 204 NW2d 141 (1972) (tree by the side of road). The gist of these cases is that the statutory duty extends to the maintenance of conditions that affect the safety of motorists using the improved portion of the highway designed for vehicular travel.1
*593In the present case, we need to determine whether the tree affected the safety of motorists using the shoulder of the road. We are uncertain as to whether decedent’s vehicle struck the tree while the vehicle was still completely on the shoulder or whether it collided with the tree only after one or more of its wheels had left the shoulder. If the tree was positioned such that the average vehicle could have struck the tree without any of the vehicle’s wheels leaving the shoulder, the tree would affect the safety of motorists using the shoulder. Under such circumstances, the defendant’s duty to keep the road reasonably safe would extend to the maintenance of the tree. The record, however, does not disclose whether those circumstances existed in this case. Consequently, we are unable to decide whether the defendant had a duty to maintain the tree. If, on retrial, the duty issue is brought before the court, the court shall decide the issue by determining whether the circumstances creating that duty exist.
Fourth, the plaintiff contends that the deposition of defendant’s expert, Dr. Richard Stockmar, should not have been admitted into evidence. Stockmar opined that the blood alcohol level of plaintiff’s decedent is "a reasonable explanation for erratic driving”. Plaintiff argues that that testimony lacked a foundation.
In order to establish a foundation for the admissibility of a blood sample analysis, it must be shown:
"(1) that the blood was timely taken (2) from a particular identified body (3) by an authorized licensed physician, medical technologist, or registered nurse designated by a licensed physician, (4) that the instruments *594used were sterile, (5) that the blood taken was properly preserved or kept, (6) and labeled, and (7) if transported or sent, the method and procedures used therein, (8) the method and procedures used in conducting the test, and (9) that the identity of the person or persons under whose supervision the tests were conducted be established.” Gard v Michigan Produce Haulers, 20 Mich App 402, 407-408; 174 NW2d 73 (1969), lv den 383 Mich 777 (1970).
Plaintiff asserts that the fourth and fifth conditions were not met. As to the fourth requirement, the physician taking the sample testified that he took the blood sample from the heart in order to avoid contaminating the sample. The purpose of using sterile instruments is to prevent contamination of the blood samples. We find that the physician’s testimony is sufficient to establish that the samples were taken without contaminating them. As to the fifth condition, plaintiff points out that Sergeant Stack testified that he could not remember whether the vial containing the blood of plaintiff’s decedent contained a preservative. However, in Mason v Lovins, 24 Mich App 101, 110; 180 NW2d 73 (1970), this Court held that where "the witness testifies that he always follows a particular procedure, he may on that basis testify that he did so in the case at hand”. David. DeVries, who did the blood analysis, testified that a preservative was routinely placed in vials that were included in the kits used to take blood samples. Thus, the fifth condition was met.
Plaintiff also maintains that Dr. Stockmar was not qualified to testify as to the effect of alcohol on behavior. Generally, it is within the trial court’s discretion to admit or exclude expert testimony and its decision will not be disturbed unless it is an abuse of discretion. Groth v DeGrandchamp, 71 Mich App 439, 443; 248 NW2d 576 (1976), lv den *595400 Mich 808 (1977). In Groth, supra, the trial court did not allow the witness who had analyzed the alcohol content of the blood of plaintiffs decedent to testify as to the effect of such an alcohol level on intoxication. This Court affirmed on the ground that "the witness lacked the qualifications necessary to permit her to testify as an expert on the effect of a given blood alcohol content on an individual * * 71 Mich App 444. Stockmar received a Ph.D. in biochemistry but had no training in the effects of alcohol on an individual. His testimony was based solely on what he had read in two books. An expert witness must be qualified as an expert by "knowledge, skill, experience, training or education”. MRE 702. Inasmuch as Stock-mar had studied recognized authorities in the area, he may be considered to have enough "knowledge” of the effects of alcohol blood levels on behavior to be considered an expert in that subject. At least, we cannot say that, in considering him as such, the trial court abused its discretion.
Fifth, plaintiff claims that the trial court erred in sustaining defendant’s objection to certain opinion testimony offered by plaintiffs expert, Sergeant Capman. Plaintiffs attorney asked Capman if, in his opinion, the condition of the shoulder affected a vehicle as it traversed the shoulder. The court sustained defense counsel’s objection on the ground that Capman was not qualified to give such an opinion.
In Link v McCoy, 39 Mich App 120, 123; 197 NW2d 278 (1972), it was said:
"Unless it can be established that the testifying officers are so schooled and experienced that their measure of skill and special knowledge decidedly transcends the capabilities of an average juror, who has been made *596fully aware of the physical facts, their point of impact opinions should not be received.”
The record discloses that Capman had received considerable education in the area of traffic investigation and traffic safety. Specifically, he attended a course in accident reconstruction at Northwestern University, a similar course at Michigan State University and had been teaching accident-investigation courses at the local police academy. In addition, Capman had considerable experience in reconstructing accidents. Given his education and experience in accident reconstruction, Capman was clearly qualified to offer his opinion on how the shoulder of the road would have affected a vehicle traveling on it. The trial court abused its discretion in ruling otherwise.
On cross-appeal, defendant argues that the trial court erred in denying its motion for directed verdict. Defendant argues, first, that its duty extends only to persons using the shoulder for one of its intended purposes and that no evidence was received that decedent used the road for one of those purposes. But MCL 691.1402; MSA 3.996(102) does not place such a condition on the duty of a county road commission. Why decedent left the road may be relevant to decedent’s negligence, but it is not relevant to defendant’s duty to properly maintain the road for the benefit of decedent. Second, defendant argues that, because the jury awarded no damages, plaintiff’s allegations of error are moot. Defendant has cited no authority for such a position and we must reject it.
Because of numerous reversible errors, the judgment below is reversed and a new trial is ordered.
Reversed and remanded. No costs, neither party having prevailed in full.
For example, in Lynes v St Joseph Road Comm, supra, p 58, this Court said:
"In the instant case a stop sign had been placed by the proper authorities for the purpose of controlling the flow of traffic. The defendant had the duty, imposed by statute, to place and maintain the stop sign in a manner to make travel upon the highways reasonably safe.”
The Court went on to reject the defendant’s argument that its duty "to keep the highways safe and fit for travel [is] limited to the pavement itself and whatever equipment physically touches the pavement”. 29 Mich App 59. The court concluded:
"Traffic signals which control the flow of traffic are an integral part of the improved portion of the highway. The presence or absence of such signals, as well as the conditions in which they are maintained, directly relates to the statutory duty imposed upon the defendant to *593maintain the highway in a condition safe and fit for travel.” 29 Mich App 59.