Utah Court of Appeals

What constitutes criminal negligence in Utah negligent homicide cases? State v. Boss Explained

2005 UT App 520
No. 20040714-CA
December 8, 2005
Affirmed

Summary

Defendant was convicted of negligent homicide after attempting to pass two or more cars on a two-lane highway at 70 mph in the face of oncoming traffic, then making sharp steering corrections that caused her vehicle to lose control and strike an oncoming car, killing a four-year-old passenger. The Court of Appeals affirmed, finding sufficient evidence of both criminal negligence and causation.

Analysis

In State v. Boss, the Utah Court of Appeals clarified the boundaries between ordinary negligence and criminal negligence in the context of vehicular negligent homicide prosecutions.

Background and Facts

Defendant Dorothy Boss was driving westbound on Highway 73 when she attempted to pass two or more cars by entering the eastbound lane despite oncoming traffic. Traveling at 70 mph in a 65 mph zone, Boss made aggressive steering maneuvers to return to the westbound lane, causing her vehicle to lose control and slide sideways into the eastbound lane. Her car struck an oncoming vehicle, killing four-year-old Jaycee Hathaway. Expert testimony indicated Boss’s vehicle likely hit a driveway that acted as a ramp, causing the car to lift and roll onto its side.

Key Legal Issues

Boss challenged her negligent homicide conviction on two grounds: (1) her conduct did not rise to the level of criminal negligence, and (2) her actions were not the proximate cause of the collision. Under Utah Code section 76-5-206(1), negligent homicide requires that the actor, acting with criminal negligence, causes another’s death.

Court’s Analysis and Holding

The court distinguished this case from State v. Larsen, where a defendant’s simple failure to see an oncoming car during a left turn was deemed insufficient for criminal negligence. Here, Boss’s conduct involved multiple deviations from the standard of care: excessive speed, improper passing maneuvers in the face of oncoming traffic, and aggressive steering corrections. The court found this combination created a “substantial and unjustifiable risk of death” and constituted a “gross deviation from the standard of care that an ordinary person would exercise.”

Regarding causation, the court applied the principle from State v. Hallett that when a party’s wrongful conduct creates a condition of peril, it can be the proximate cause of resulting injury even when other factors contribute to the harm.

Practice Implications

This decision reinforces that criminal negligence requires more than ordinary carelessness—it demands conduct that grossly deviates from reasonable care standards. For practitioners, the case illustrates how multiple traffic violations combined with excessive speed can elevate conduct from civil negligence to criminal culpability. The court’s emphasis on “repeated deviations” suggests that isolated acts of poor judgment may not suffice, but a pattern of dangerous driving behaviors can support criminal negligence charges.

Original Opinion

Link to Original Case

Case Details

Case Name

State v. Boss

Citation

2005 UT App 520

Court

Utah Court of Appeals

Case Number

No. 20040714-CA

Date Decided

December 8, 2005

Outcome

Affirmed

Holding

Attempting to pass multiple vehicles on a two-lane highway at excessive speed in the face of oncoming traffic, followed by aggressive steering that causes loss of vehicle control, constitutes criminal negligence sufficient to support a negligent homicide conviction.

Standard of Review

Sufficiency of evidence claims: evidence is sufficient unless sufficiently inconclusive or inherently improbable that reasonable minds must have entertained a reasonable doubt, examining evidence in light most favorable to the verdict

Practice Tip

When challenging sufficiency of evidence in criminal cases, focus on whether the evidence shows conduct that constitutes a gross deviation from ordinary care standards, not merely negligent behavior.

Need Appellate Counsel?

Lotus Appellate Law handles appeals before the Utah Court of Appeals, Utah Supreme Court, California Court of Appeal, and the United States Court of Appeals for the Tenth Circuit.

Related Court Opinions

    • Utah Court of Appeals

    Martin v. Kristensen

    July 26, 2019

    Temporary possession orders in divorce proceedings do not excuse a party from unlawful detainer damages when those orders were issued after the unlawful detainer commenced and did not bind the property owner who was not a party to the divorce case.
    • Divorce
    • |
    • Property Rights
    • |
    • Temporary Orders
    • |
    • Unlawful Detainer
    Read More
    • Utah Court of Appeals

    Zions Gate v. Oliphant

    May 1, 2014

    An LLC manager lacks authority to bind the company when the articles of organization expressly require consent of all managers, and filing those articles with the state provides constructive notice to third parties of such limitations.
    • Contract Interpretation
    • |
    • Statutory Interpretation
    • |
    • Summary Judgment
    Read More
About these Decision Summaries

Lotus Appellate Law publishes these summaries to keep practitioners informed — not as legal advice. Each case turns on its own facts. If a decision here is relevant to your matter, we’re happy to discuss it.