#### Frank H. AUTREY and Betty Autrey, his wife, Appellants, v. Anne M. CARROLL, Executrix of the Estate of Frank E. Carroll, deceased, Appellee.

No. 69-72.

District Court of Appeal of Florida. Third District.

Oct. 28, 1969.

Rehearing Denied Nov. 19, 1969.

Pearson, C. J., dissented.

*698Snyder, Young & Stern, No. Miami Beach, and Michael H. Oritt, Miami, for appellants.

Blackwell, Walker & Gray and James E. Tribble, Miami, for appellee.

Before PEARSON, C. J., and CHARLES CARROLL and SWANN, JJ.

PER CURIAM.

This is an automobile accident case. The appeal is by the plaintiff below from a judgment entered for the defendant, based on a jury verdict.

Plaintiff’s automobile was involved in a head-on collision with one driven by ap-pellee’s decedent, Frank E. Carroll, who was found dead at the place of the accident, his death being attributed to heart failure.

The collision occurred in Miami, on Northeast Second Avenue between Seventh and Eighth Streets. There were lanes for northbound traffic and for southbound traffic. Carroll was driving north in the northbound lane. A double yellow line divided it from the southbound traffic lane. Carroll’s car swerved to the left, into the southbound lane, resulting in a head-on collision with the plaintiff’s automobile.

There was medical evidence from which the jury could find that Carroll had suffered a heart attack prior to the impact, and that the collision resulted from the sudden incapacity or death of Carroll, rather than from negligent driving. In addition thereto, opinion testimony of a traffic expert was introduced to supplement and support that reason for the accident. The latter involved hypothetical questions, based on the circumstances of the collision and the condition and position of Carroll’s body in his car as observed after the collision. Appellants claim error in the trial court’s ruling admitting such opinion testimony. We find no harmful or reversible error therein. Also, we have considered and find to be without merit the contentions presented by appellant with reference to the giving of certain jury charges and the denial of certain requested charges.

Affirmed.

PEARSON, Chief Judge

(dissenting).

A party may not properly ask his expert witness a hypothetical question unless that question is based on some previous testimony or other evidence in the record. Atlantic Coast Line R. Co. v. Shouse, 83 Fla. 156, 91 So. 90 (1922). In Point One of her brief the appellee tries to show she has met the requirement of the foregoing rule. She lists 16 assumptions made in a hypothetical question put to traffic expert Dollar and 16 items as supporting testimony for the assumptions. Two of those items are portions of expert opinion testimony previously given by traffic expert Dollar. Since “[t]he opinion of the expert cannot constitute proof of the existence of the facts necessary to the support of the opinion”,1 the two items could not legitimately be used as bases for the hypothetical question put to Dollar. The court should therefore not have permitted the question to be asked or answered. Because jurors are human, they are apt to accept the conclusion of an expert witness without referring to the basis of that conclusion. See 2 Wigmore on Evidence, § 682, p. 808. Courts should therefore exercise extreme caution in the area of expert witness testimony. Here the trial court was not cautious enough.

For the foregoing reasons I would hold that the court erred in permitting the ap-pellee over appellants’ objection to put the hypothetical question to Dollar and would remand the cause for a new trial.

1

. Arkin Construction Company v. Simpkins, Fla.1957, 99 So.2d 557, 561. Cf. 58 Am.Jur., Witnesses, § 855, p. 484.