
191 S.E.2d 395 (1972)
16 N.C. App. 95
STATE of North Carolina
v.
Andrew Worth ALEXANDER.
No. 7221SC628.
Court of Appeals of North Carolina.
September 20, 1972.
Certiorari Denied November 8, 1972.
*397 Atty. Gen. Robert Morgan by Asst. Atty. Gen. William W. Melvin and Associate Atty. Gen. Richard B. Conely for the State.
Powell & Powell by Harrell Powell, Jr., Winston-Salem, for defendant appellant.
Certiorari Denied by Supreme Court November 8, 1972.
MALLARD, Chief Judge.
Defendant has twenty-six assignments of error. Three of these assignments of error are not brought forward in defendant's brief, numbers 2, 9 and 21, and are therefore deemed abandoned. See Rule 28 of the Rules of Practice in the Court of Appeals.
Defendant assigns as error the denial of his motion for judgment as of nonsuit at the close of all the evidence. There was ample evidence that the defendant was operating his automobile on this occasion at a speed in excess of the posted speed limit, in a careless and reckless manner, while under the influence of intoxicating beverages, and that the death of the deceased victim was proximately caused by the culpable negligence of the defendant. Culpable negligence in criminal cases has been defined by our Supreme Court in many cases, among which are: State v. Gurley, 253 N.C. 55, 116 S.E.2d 143 (1960); State v. Hancock, 248 N.C. 432, 103 S.E.2d 491 (1958); and State v. Cope, 204 N.C. 28, 167 S.E. 456 (1933). When the law of culpable negligence is applied to the evidence in this case, we hold that defendant's *398 motion for judgment as of nonsuit was properly overruled.
Defendant assigns as error the admission into evidence of the testimony of arresting Officer Lloyd Kenneth Nelson that defendant was driving on a restricted driver's license. Defendant contends such evidence was irrelevant and incompetent. However, evidence that defendant was driving on a restricted driver's permit which prevented him from legally operating his vehicle after 8:00 p. m. until 5:00 a. m. the next day was relevant and competent on the issue of criminal negligence, as indicating that defendant's motive for speeding was to ensure his arrival home in Raleigh before the 8:00 p. m. deadline. Stansbury, N. C. Evidence 2d, § 83, n. 72.
Defendant also contends that the court erred in permitting State's witness Harmon to give his opinion as to the intoxicated condition of the defendant when he first saw the defendant on that date at approximately 10:45 p. m. Mr. Harmon testified he gave the defendant a breathalyzer test on this occasion. In view of the testimony of the arresting officer, Nelson, that the defendant was under his observation all of the time from the arrest until after the breathalyzer test and that during that time he did not see the defendant eat or drink anything, it was not error to permit Mr. Harmon to give his opinion as to the intoxicated condition of the defendant approximately three and a half hours after the defendant was arrested.
Defendant assigns as error the admission into evidence of the results of a breathalyzer test given defendant almost four hours after the collision, which test gave a reading of .21 percent by weight of alcohol in his blood. "Obviously, the breathalyzer can measure only the amount of alcohol which is in a person's blood at the time the test is given. . . . [I]t is undoubtedly true that the sooner after the event the test is made, the more accurate will be the estimate of blood alcohol concentration at the time of the act in issue." State v. Cooke, 270 N.C. 644, 155 S.E.2d 165 (1967). The question whether the existence of intoxication at a particular time is competent to show the existence of that condition at another time is a question of materiality, to be determined upon the facts of each particular case, including the length of time intervening and the showing, if any, whether the condition remained unchanged. State v. Davis, 265 N.C. 720, 145 S.E.2d 7 (1965); State v. Oldham, 10 N.C.App. 172, 177 S.E.2d 769 (1970). The testimony of Officer Nelson was that defendant had consumed no alcohol during the interval between his arrest at the scene of the collision and the test. We hold that a breathalyzer test given under the facts of this case four hours after the collision was relevant and of probative value.
Defendant contends it was error to admit into evidence testimony that on 7 December 1970 defendant had refused to take a breathalyzer test. Although incompetent even for the purpose of impeachment of defendant's testimony, we hold that such evidence was not prejudicial in view of defendant's subsequent admission that he was arrested for driving under the influence of intoxicating liquor in December 1970 and was convicted of that crime in February 1971.
Defendant assigns as error the failure of the court to give instructions to the jury limiting consideration of the evidence of commissions of prior crimes to impeachment purposes only. When cross-examining the defendant, the solicitor, without objection, questioned defendant as to whether he had been convicted of specific prior criminal offenses. In the court's charge to the jury, the judge restated as a portion of the State's evidence that on cross-examination defendant admitted having been convicted of certain specific crimes. Admissions as to convictions of unrelated prior criminal offenses are not competent as substantive evidence, but are competent as bearing upon defendant's credibility as a witness. Stansbury, N.C. Evidence 2d, § 112; State v. Goodson, 273 N.C. 128, 159 S.E.2d 310 (1968). Absent a request, the failure of the court to give such an instruction was not error. State v. *399 Goodson, supra; State v. McKinnon, 223 N.C. 160, 25 S.E.2d 606 (1943).
Defendant assigns as error a portion of the judge's charge to the jury concerning culpable or criminal negligence. Defendant contends the judge failed to properly instruct the jury that an unintentional violation of a safety statute, without more, is not culpable negligence and cited State v. Gurley, 253 N.C. 55, 116 S.E.2d 143 (1960). We do not agree. Judge Armstrong instructed the jury as follows:
"Members of the jury, I further instruct you that an unintentional violation of a statute . . . unaccompanied by recklessness or probable consequences of a dangerous nature when tested by the rule of reasonable foresight is not such negligence as imports criminal responsibility. However, . . . if the inadvertent, that is, or the unintentional violation of a prohibitory statute . . . be accompanied by recklessness or probable consequences of a dangerous nature when tested by the rule of reasonable foresight, amounting altogether to a thoughtless disregard of consequences, or a heedless indifference to the rights and safety of others, then such negligence, if death proximately ensues, would be criminal negligence, and the actor would be guilty of involuntary manslaughter."
The above-quoted portion of the judge's charge to the jury complies with the requirements of State v. Gurley, supra.
The defendant assigns as error the instructions of the court that a motion picture of the defendant was offered by the State to corroborate two of the State's witnesses, Dr. Podgorny and Officer Nelson, or to illustrate their testimony. In his brief the defendant cites no authority in support of his position, and the State cites no authority supporting its contention that the motion picture was competent to "corroborate" the witnesses. However, immediately prior to the challenged instructions, the solicitor had, in offering the motion picture, stated that he was offering it "for the purpose of corroborating" the two witnesses, and the defendant not only failed to object but stated, "We have no objections." The defendant, by stating he had no objections, agreed to the introduction of the motion picture for the purpose of "corroborating" the two witnesses, and he cannot complain because the trial judge instructed the jury as to the purpose for which he agreed it might be received. We do not think that limiting the consideration of the photograph to corroborative purposes (as well as illustrative) was prejudicial error in this case. See State v. McKissick, 271 N.C. 500, 157 S.E.2d 112 (1967).
The defendant has other assignments of error relating to the charge, but when it is read contextually, we are of the opinion and so hold that no prejudicial error appears in the charge. The defendant has had a fair trial, free from prejudicial error.
No error.
CAMPBELL and BRITT, JJ., concur.
