Utah's Unique Rule of Evidence Regarding Traffic Code Violations

Utah has a unique rule of evidence. Utah Rule of Evidence 416 (Violation of Traffic Code Not Admissible) states that

Evidence that a person was convicted of an infraction or a class C misdemeanor under Utah Code Title 41, Chapter 6a, is not admissible:

(a) to prove the person acted negligently or otherwise wrongly, or

(b) to impeach the person’s testimony on those issues.

It's not hard to see how this Rule operates. Imagine that Dana fails to yield right of way to Victoria at an intersection and crashes into her. Subsequently, Dana is convicted of failing to yield the right of way. Then, Victoria sues Dana for injuries she suffered in the accident. Rule 416(a) would prohibit Dana's conviction from being admissible to prove she was driving negligently or otherwise wrongfully when she struck Victoria. And Rule 416(b) would prohibit Victoria from using Dana's conviction to impeach Dana's credibility when she testifies in her defense.

Conversely, it's less clear why the Rule exists. According to the Utah Practice Series, 

Issues of whether a conviction under a traffic violation should be admissible to prove negligence, a wrongful act, or for impeachment purposes often arise under a relevancy analysis. Rather than subject such evidence to a case-by-case analysis weighing the probative value of a traffic violation against the Rule 403 unfair prejudicial effect, the Court adopted Rule 416.

So...was this just laziness? As the Practice Series notes, there are circumstances where a violation of the traffic code would be admissible and other circumstances where violation of the traffic code would be irrelevant (or where it's probative value would be substantially outweighed). But, given this, why not leave admissibility up to judges on a case-by-case basis? And why create a blanket ban when such violations can be quite relevant and important in some cases?

-CM