[¶ 1.] Drivers must slow to fifteen miles-per-hour when approaching an intersection if they have an obstructed view of other vehicles entering the intersection. Was the trial court correct in applying this rule to an intersection on a through highway? Because such highways are designed to allow traffic to maintain constant speed, we conclude the obstructed view rule was inapplicable. The court also erred in instructing the jury that failure to use a seatbelt can be considered a failure to mitigate damages. We find no abuse of discretion, however, in admitting evidence of plaintiffs purpоrted investment income. We affirm in part, reverse in part, and remand for a new trial.
Facts
[¶2.] On August 26, 1993, Jeffrey Davis was driving north on Russell Street in Sioux Falls. Russell is a four-lane thoroughfare running north and south, with a grassy median. As he approached the Louise Avenue intersection, Susan Knippling was turning left onto Russell from Louise. Neither onе could see the other because their view was obstructed by a gravel truck stopped in the left turn lane on Russell. Knippling drove directly in front of Davis and he broadsided her vehicle. Davis was not wearing a seat-belt. He hit his head on the windshield, was rendered momentarily unconscious, and suffered multiple injuriеs.
[¶ 3.] Davis brought suit against Knippling alleging negligence in failing to yield to oncoming traffic. In her answer, Knippling denied any negligence, and asserted Davis was contributorily negligent and failed to mitigate his damages. The court denied Davis’s motions in limine to prohibit mention of his failure to use a seatbelt and evidence of his business profits. The jury was instructed Davis may be considered contribu-torily negligent if he violated the statute which prohibits traveling more than fifteen miles per hour while crossing an intersection with an obstructed view. After a four-day trial, the jury returned a verdict for Davis, awarding him $6,824 in damages. On appeal, Davis contends the court erred by (1) instructing the jury that it may consider failure to use a seatbelt as evidence of failure to avoid or minimize injuries; (2) instructing that failure to slow to fifteen miles-per-hour at the intersection could be contributory negligence; and (3) admitting evidence of Davis’s investment income in determining loss of еarning capacity.
Standard of Review
[¶ 4.] Under our standard of review, we construe jury instructions as a whole to learn if they provided a full and correct statement of the law.
Sommervold v. Grevlos,
Analysis and Decision
1. Failure to Slow at Obstructed View Intersection
[¶5.] Citing our holding
Robbins v. Buntrock,
When approaching within fifty feet of and when traversing an intersection оf highways when the driver’s view is obstructed the maximum lawful speed shall be fifteen miles per hour. A driver’s view is obstructed if at any time during the last fifty feet of his approach to such intersection, he does not have a clear and uninterrupted view of such intersection and of the traffic upon all of the highways entering such intersection for a distance of two hundred feet from such intersection. A violation of this section is a Class 2 misdemeanor,
(emphasis added). Although Davis may have had an obstructed view of traffic approaching the intersection, giving an instruction based upon this statute was error. The facts in Robbins were quite dissimilar: the intersection was not one govеrned by a yield sign controlling cross traffic on a through highway as we see here.
[¶ 6.] Knippling was stopped at a yield sign on Louise Avenue just before turning left onto Russell Street and into Davis’s path. Her view of oncoming traffic was obstructed by a gravel truck which had pulled into the left-hand turn lane on Russell. Davis’s view of trаffic on, Louise Avenue was probably also obstructed — he did not recall a track in the turn lane — but he was entitled to rely upon the yield sign controlling traffic turning onto Russell.
[¶ 7.] In South Dakota, state and local authorities designate through highways “by erecting at the entrances thereto from intersecting highways stop or yield signs.”
Musilek v. Stober,
[¶ 8.] On the other hand, “[tjhis Court has repeatedly held that the failure of a driver of a motor vehicle to see a [favored] vehicle ... at an intersection constitutes negligence .... ”
Kallis v. Beers,
375 N.W.2d
*528
642, 644 (S.D.1985);
see also Vlach v. Wyman,
[¶ 9.] We need not decide whether the court’s erroneous obstructed view instruction wаs alone prejudicial, because the jury was also instructed it may find Davis eontribu-torily negligent if he was exceeding the posted speed limit at the time of the accident.
See
SDCL 15-6-61. In a civil case, if a general verdict is handed down and the jury could have decided the case on two theories, one рroper and one improper, the reviewing court will assume it was decided on the proper theory.
Jack Rabbit Lines, Inc. v. Neoplan Coach Sales, Inc.,
2. Failure to Use Seatbelt as Failure to Mitigate Damages
[¶ 10.] Drivers and other persons in the front seat of passenger vehicles must use seat belts in South Dakota. SDCL 32-38-1 (effective July 1,1994). However, by statute, proof of failure to wear a seat belt may not be introduced as evidence in any civil litigation on the issue of mitigation of damages. SDCL 32-38-4. As the accident occurred in August 1993, these enactments are inapplicable to this ease.
[¶ 11.] Relying upon dicta in
Kusser v. Feller,
The jury also could have concluded that Kusser failed to avoid or minimize injury by not wearing a seat belt. The jury was instructed about avoiding or minimizing injury. However, closing argument was not recorded so it is difficult to determine the impact of this point.
Id.
at 621-22. Yet the question — whether not wearing а seatbelt can be considered failure to mitigate damages — was not directly at issue there. The
Kusser
Court may have supposed a basis for the jury’s position, but it neither endorsed a rule, nor relied on one to decide the ease. Accordingly, despite the existence of statutes controlling the issue for future cases, we must decide whether the mitigation doctrine applied to injured plaintiffs not wearing seatbelts before the effective date of these enactments. Whether the doctrine applies to the use of seatbelts is a question of law.
Welsh v. Anderson,
[¶ 12.] A clear majority of states have judicially refused to admit evidence of a plaintiffs nonuse of an, available seatbelt as proof of failure to mitigate damages likely to
*529
occur in an automobile accident.
See Welsh,
[¶ 13.] A duty to mitigate ordinarily arises only after a tortfeasor’s negligent act.
Welsh,
[¶ 14.] The question then remains whether the error was prejudicial.
DDL Cattle Co., Inc.,
*530 3. Evidence of Davis’s Income
[¶ 15.] Generally,' trial courts have broad discretion in questions relating to admission of evidence.
Schaffer v. Edward D. Jones & Co.,
[¶ 16.] Though we have not had the opportunity to decidé this issue before, the established rule elsewhere prohibits consideration of business profits and investment income in calculating lost earning capacity.
4
Holland v. Ratliff,
[¶ 17.] Over Davis’s standing objection, the trial court admitted evidence on income and profits he received from Davis Casino, Inc., a video lottery business, and J & J Partnership, which owns and manages an apartment building. Davis claims he does not actively participate in the day-to-day operations of either venture, and, as such, the law makes income from these sources irrelevant to finding loss of earning capacity. He is correct in stating the general prоposition, but the evidence provides considerable support for not applying the rule here. In the tax years preceding his accident, Davis reported to the IRS that he had received substantial amounts of nonpassive income from both Davis Casino, Inc. and J & J Partnership. Even though he testifiеd that he would receive this income whatever the extent of his involvement, the fact remains he reported the income to the IRS as nonpassive, thus suggesting he was actively involved in the creation and receipt of this income. Davis also testified that he received an annual salary from Davis Casino, Inc., which he reported to the IRS as W-2 income for work he performed for the casino. Lastly, he testified that although he was not considered a day-to-day employee of either entity, he was actively involved in the management and decision-making processes of both businesses. Kniрpling maintains, and we agree, that Davis cannot keep from the jury these facts, nor his representations to the IRS. His income from these businesses may be from passive investment, but Knippling should not be thwarted from trying to prove the contrary. Allowing parties to expose each other’s inconsistent positions, assists the outermost aim of our rules that “truth may be ascertained and proceedings justly determined.” SDCL 19-9-2; 19-12-1. The trial court did not abuse its discretion in admitting evidence of Davis’s business income as relevant to his claim for loss of earning capacity.
[¶ 18.] Affirmed in part, and reversed in part, and remanded for a new trial.
Notes
. SDCL 32-29-2 provides:
The department of transportation with reference to state highways and local authorities with reference to highways under their jurisdiction may designate main traveled or through highways by erecting at the entrances thereto from intersecting highways stop or yield signs. All such signs shall be illuminаted at night or so placed as to be illuminated by headlights of an approaching vehicle.
. New York leads those states holding failure to wear an available seatbelt may constitute failure to mitigate damages. See
Spier v. Barker,
. There is some dispute in the record over the actual amount of medical expenses attributable to Davis's injuries stemming from this accident. Davis contends he incurred $39,372.76 in mеdical bills directly caused by the accident. Knip-pling does not contest that Davis incurred $10,-369.87, but argues the remainder is attributable to an incident which occurred approximately three months after the accident when Davis' was getting out of bed and his neck popped causing great discomfort and ultimately resulting in surgery to remove a herniated disk fragment. Knip-pling contends this surgery is not causally connected to the accident.
. An exception to the rule provides “only when a business generates profits primarily from the personal endeavors or skills of its owner, may such profits be used in determining such owner’s lost earning capacity.”
Mihalek v. Cichowski, 4
Conn.App. 484,
