At the outset, we note that defendant’s brief does not contain a non-argumentative summary of the material facts as required *417by Rule 28(b)(3), Rules of Appellate Procedure. Failure to comply with this rule slows our work by requiring us to read through the entire lengthy transcript to determine the facts of the case. We have, however, elected to consider the case on its merits.
[1] Defendant’s first assignment of error is that the trial court erred in denying his motion to suppress the evidence of the bottles found in his briefcase. Defendant bases his argument on appeal solely on the following sentence from G.S. 18A-21(c) [repealed by Session Laws 1981, c. 412, s. 1, effective 1 January 1982]:
Provided, that nothing in this section shall be construed to authorize any officer to search any vehicle or other conveyance or baggage of any person without a search warrant duly issued, except where the offiper sees or has absolute personal knowledge that there is intoxicating liquor ... in the vehicle or baggage.
This sentence in G.S. 18A-21, however, pertains only to searches of vehicles used for illegal transportation of alcohol. Obviously, defendant’s reliance on G.S. 18A-21 is mistaken because at trial, in Superior Court, he was charged with manslaughter, failure to stop at a stop sign, and driving under the influence, not illegal transportation of alcohol. Under these circumstances, G.S. 18A-21 is inapplicable.
Although defendant’s present argument concerning his motion to suppress is based solely on G.S. 18A-21, at trial he argued that the search of his briefcase was unconstitutional. The trial court properly rejected this argument. Officer Jones testified that he had been told by a Trailways employee not to allow anyone to remove baggage without providing identification. After identifying and releasing one bag, Jones picked up an untagged and unmarked briefcase lying beside defendant’s seat and opened it. In the briefcase he found three liquor bottles and defendant’s identification. The State argues that the warrantless search was not unconstitutional because it qualified as an inventory search, permitted under South Dakota v. Opperman, 428 U.S. 364, 49 L.Ed. 2d 1000, 96 S.Ct. 3092 (1976). Opperman, however, does not support the State’s argument. Opperman applies only to the situation where a vehicle is impounded by the police, and the police routinely inventory and secure the contents of the vehicle. This is done for the protection of the owner’s property, to protect the *418police from claims or disputes over stolen property, and to protect the police from danger. An inventory, pursuant to standard police procedures, is not unreasonable under the Fourth Amendment.
The situation in the instant case is different from Opperman because the vehicle was not impounded and its contents were not inventoried. It is, however, analogous to the situation in State v. Francum, 39 N.C. App. 429, 250 S.E. 2d 705 (1979). In Francum, defendant had wrecked his car, and after he was taken to the hospital, a State trooper noticed a paper bag lying beside the upturned car. The officer opened the bag and examined the contents, later determined to be hashish, barbiturates, and LSD. The Court held that although the officer’s inspection of the bag’s contents did not fall within the inventory search exception set forth in Opperman, the same considerations justifying an inventorying of property in an automobile that has properly been taken into police custody are applicable. The primary justification for the search is to safeguard the individual’s property from loss or theft. The Court held that it was reasonable for the officer to look inside the paper bag to determine whether there was anything valuable belonging to the owner that should be held for safekeeping. The paper bag may have been worthless garbage which someone threw from a passing car, or it may have belonged to the owner of the wrecked car. It was impossible to tell from merely looking at the outside of the bag, so, under those circumstances the search was found to be reasonable. The search was not based upon probable cause, it was to identify the owner of the property so that it could be protected from theft. Had it been a briefcase or suitcase it would have been clear that it was valuable, had fallen out of the car, and belonged to the owner of the car, and a warrantless search would have been unjustifiable at that time. In the instant case, the wrecked vehicle was a bus with many passengers, not a private car. In Francum, the question the officer faced was whether the bag belonged to the owner of the car. In the instant case the question was which passenger owned the briefcase. Although defendant contends that the briefcase was beside his seat and obviously belonged to the driver, it is quite likely the officer reasoned that in the confusion of the accident a passenger’s briefcase could have ended up beside the driver’s seat. The purpose of the officer’s search was analogous to the pur*419pose in Francum: to determine the owner of the property so the officer could safeguard its contents. Under these circumstances, the search was not unreasonable under the Fourth Amendment.
[2] Defendant’s second assignment of error is that the trial court erred in allowing evidence of speed limit signs because defendant had been found not guilty of speeding in district court. We do not agree. When Trooper Rector was describing the intersection where the accident occurred, he said “There are two speed limit signs on this particular road. After you turn off on [Route] 18 there is the first sign which is approximately a hundred feet onto Bethel Road. After the first sign there is another thirty-five miles an hour speed sign, and it is approximately five tenths of a mile from N.C. 18.” Defendant’s subsequent motion to strike was overruled, but the court instructed the jury not to consider the testimony about the speed limit signs. Since the judge gave the jury a limiting instruction, defendant was not prejudiced by the denial of his motion to strike. In general, the jury is presumed to have heeded a limiting instruction, whether the instruction has removed the prejudice depends on the nature of the evidence and the circumstances of the case. State v. Gregory, 37 N.C. App. 693, 247 S.E. 2d 19 (1978). Here, Rector made no reference as to whether defendant was speeding; he merely said there were two speed limit signs on the road. There was no error prejudicial to defendant.
[3] Defendant’s third assignment of error is that the trial court erred in admitting evidence of his refusal to take the breathalyzer test. Evidence of refusal to take the breathalyzer test is admissible as provided in G.S. 20-139.1(f):
If a person under arrest refuses to submit to a chemical test or tests under the provisions of G.S. 20-16.2, evidence of refusal shall be admissible in any criminal action arising out of acts alleged to have been committed while the person was driving or operating a vehicle while under the influence of alcoholic beverages.
The admission into evidence of defendant’s refusal to take a breathalyzer test does not violate his Fifth Amendment right against self-incrimination, South Dakota v. Neville, 459 U.S. ---, 74 L.Ed. 2d 748, 103 S.Ct. 916 (1983), and is not unconstitutional under North Carolina law. State v. Paschal, 253 N.C. 795, 117 S.E. *4202d 749 (1961); State v. Flannery, 31 N.C. App. 617, 230 S.E. 2d 603 (1976). “The established rule in this jurisdiction is that ‘[t]he scope of the privilege against self-incrimination, in history and in principle, includes only the process of testifying by word of mouth or in writing, ie., the process of disclosure by utterance. It has no application to such physical, evidential circumstances as may exist on the accused’s body or about his person.’ ” State v. Paschal, 253 N.C. at 797, 117 S.E. 2d at 750-751, quoting State v. Rogers, 233 N.C. 390, 399, 64 S.E. 2d 572, 578-579 (1951).
[4] Defendant’s fourth assignment of error is that the trial court erred in refusing to permit Trooper Rector to testify as to whether defendant’s walk could have been due to his bruised hip. This assignment of error is overruled because defendant failed to make an offer of proof as to what the excluded evidence would have been. State v. Hedrick, 289 N.C. 232, 221 S.E. 2d 350 (1976). Moreover, it is unlikely that Rector was more qualified than the jury to reach that conclusion.
Defendant’s fifth assignment of error is that the trial court erred in failing to grant a motion for mistrial or to strike the testimony about the missing liquor bottle. This assignment of error is overruled because defendant did not present an argument following his assignment of error as required by Rule 28(b)(5), Rules of Appellate Procedure, instead he merely listed two pages of quotes from various cases. Moreover, the testimony that the Highway Patrol lost the bottle probably hurt the State more than defendant, since it may have undermined the credibility of the State’s witnesses.
[5] Defendant’s sixth assignment of error is that the trial court erred in allowing testimony about blood taken from defendant six to seven hours after the accident. The uncontradicted evidence was that the accident occurred at three o’clock, and defendant’s blood sample was taken at about seven thirty, only four and a half hours later. The results of the test were not introduced into evidence. Nevertheless, defendant argues that the evidence, that the test was made was inadmissiblé because of the lapse of time between the accident and the - test. This argument is without merit. Perhaps the results of the test would have minimal probative value since the test was made several hours after the accident. However, the evidence that defendant knew the test was *421made was offered to contradict his earlier statement that he did not know whether he had a blood test at the hospital. Such evidence was, therefore, admissible to impeach the defendant. See 1 Brandis on North Carolina Evidence § 47 (1982).
[6] Defendant’s seventh assignment of error is that the trial court erred in allowing testimony of defendant’s driving record over the past twenty years. When a defendant chooses to testify he may be cross-examined about any prior convictions, subject to the discretion of the trial judge. State v. Atkinson, 39 N.C. App. 575, 251 S.E. 2d 677 (1979). The trial judge did not abuse his discretion in allowing the cross-examination about defendant’s driving record. The evidence of defendant’s traffic violations tended to show that he pled guilty or was convicted of fourteen traffic offenses since 1956. Eleven of the violations occurred after defendant began working as a bus driver, although he testified that two or three were received when he was driving his personal car. This evidence, of course, is admissible for impeachment, and is relevant to show defendant’s lack of credibility. State v. Alford, 289 N.C. 372, 222 S.E. 2d 222, death penalty vacated, 429 U.S. 809, 50 L.Ed. 2d 69, 97 S.Ct. 46 (1976); 1 Brandis on North Carolina Evidence § 112 (1982).
Defendant’s eighth assignment of error is that the trial court erred in denying his motion to dismiss. A motion to dismiss requires the evidence to be considered in the light most favorable to the State, and, if there is substantial evidence, whether direct or circumstantial, to support a finding that the offense charged has been committed by defendant, the motion should be denied. State v. McKinney, 288 N.C. 113, 215 S.E. 2d 578 (1975). Defend-' ant does not argue that the evidence did not support a finding that he was driving under the influence; instead, he contends that the State’s evidence is not incompatible with his defense. The record is replete with evidence which, when viewed in the light most favorable to the State, supports the driving under the influence charge, and, as mentioned above, defendant admitted he ran the stop sign, and that the victim’s death was proximately caused by the collision. Clearly the trial judge did not err in denying defendant’s motion to dismiss.
[7] Defendant’s ninth assignment of error is that the trial court erred in charging the jury on manslaughter. Although given an *422opportunity to object out of the presence of the jury, defendant failed to object and cannot assign error to any portion of the jury charge. Rule 10(b)(2), Rules of Appellate Procedure. Moreover, defendant’s argument, that the court instructed the jury that defendant could be found guilty of manslaughter if they found that he failed to keep a reasonable lookout, ignores the court’s full set of instructions. The court clearly instructed the jury that if they found either that defendant failed to keep a proper lookout, failed to stop at the stop sign, or drove while under the influence, then the next thing they would have to find beyond a reasonable doubt is that defendant’s violation was culpable negligence. The trial judge twice instructed the jury as follows:
Now, members of the jury, this next thing that you must find is that the defendant’s violation, if you find that he did violate one or more of those 3 motor vehicle laws, that is, the rule that he is required to keep a reasonable lookout and the rule that he is required to stop for the stop sign and the rule and law that he shall not drive on the highway while under the influence of intoxicating liquor, if you should find that he did violate one of those laws or more, your next thing to determine and the next thing which you must find beyond a reasonable doubt is that the violation by the defendant constituted culpable negligence.
As I told you before, you must find more than just a violation to constitute culpable negligence; and in determining whether a violation of a motor vehicle law constitutes culpable negligence the violation must be considered by you along with all the facts and circumstances existing at that time relating to such violation.
Now, a violation of a safety —a motor vehicle safety law —and I want you to carefully listen to what I have to say —a violation of a motor vehicle safety law which results in injury or death will constitute culpable negligence if the violation is wilful, wanton or intentional; but where there is an unintentional or inadvertent violation of the motor vehicle law such violation, standing alone, does not constitute culpable negligence. I have told you that several times.
The inadvertent or unintentional violation of the statute must be accompanied by recklessness of probable conse*423quences 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 safety of others in order to constitute culpable negligence.
Defendant’s contention that the judge instructed the jury that defendant would be guilty of manslaughter if he merely failed to keep a proper lookout is without merit.
[8] Defendant’s tenth assignment of error is that the trial court erred in denying his motion for appropriate relief because he was denied an impartial prosecution and an unfettered right to plea bargain. He first contends that the private prosecutors exercised complete control over the case. The record, however, does not support this contention. It has long been the rule that the trial judge has discretion to permit private prosecutors to appear with the District Attorney. State v. Best, 280 N.C. 413, 186 S.E. 2d 1 (1972). Although the Assistant District Attorney did not question every witness, he conducted eight direct or cross-examinations and presented a closing argument. There is no evidence that he did not remain in charge of the prosecution as required by G.S. 7A-61. In State v. Page, 22 N.C. App. 435, 206 S.E. 2d 771, cert. denied, 285 N.C. 763, 209 S.E. 2d 287 (1974), the private prosecutor conducted every examination of the State’s witnesses, every cross-examination of defendant’s witnesses, and made the only closing argument. The Court found no error, holding that absent a showing to the contrary the Court must assume that the solicitor {ie., the District Attorney) remained in charge throughout the trial. See also State v. Chapman, 294 N.C. 407, 241 S.E. 2d 667 (1978) (the record disclosed no participation by the solicitor in the trial, although he participated in the sentencing hearing; the Court found no error).
As for defendant’s contention that he was denied an opportunity to plea bargain, the only evidence in the record on this point is a letter from Mr. Byrd, one of the private prosecutors, to defendant’s counsel in which he said he could not accept the plea bargain but he would discuss the matter with the Assistant District Attorney. This letter does not tend to show that defendant was denied an opportunity to plea bargain, it merely shows that the private prosecutor could not accept the plea. There is no evidence of any direct communication between defendant and the *424Assistant District Attorney nor any evidence that such communication was frustrated by the private prosecutors. Defendant has simply failed to produce any evidence that he was denied the opportunity to plea bargain.
We have carefully reviewed defendant’s assignments of error and find
No error.
Judges Hedrick and Arnold concur.