https://le.utah.gov/~2019/bills/static/HB0149.html

Utah’s new motorcycle lane filtering bill goes into effect, becomes law, today – 14 May 2019

As you might or might not be aware of, Utah has a new law that will affect all motorists.

What Is Lane Filtering?

Definition: “Lane filtering” means, when operating a motorcycle other than an autocycle, the act of overtaking and passing another vehicle that is stopped in the same direction of travel in the same lane.

In short: lane filtering refers to the process of a motorcyclist moving between two lanes to the front of traffic stopped at an intersection.

Motorcycles Can Only Lane Filter When:

This bill:
12          ▸     defines lane filtering;
13          ▸     allows lane filtering if a motorcycle is overtaking a vehicle that is stopped in the
14     same lane of travel and there are two or more adjacent traffic lanes in the same
15     direction of travel;
16          ▸     provides a sunset of provisions related to lane filtering, subject to review; and
17          ▸     makes technical changes.

159          (29) “Lane filtering” means, when operating a motorcycle other than an autocycle, the
160     act of overtaking and passing another vehicle that is stopped in the same direction of travel in
161     the same lane.

This defines when a person can lane filter, note that it explicitly says only motorcycles can do it:
383 (5) An individual may engage in lane filtering only when the following conditions
384 exist:
385 (a) the individual is operating a motorcycle;
386 (b) the individual is on a roadway divided into two or more adjacent traffic lanes in the
387 same direction of travel;
388 (c) the individual is on a roadway with a speed limit of 45 miles per hour or less;
389 (d) the vehicle being overtaken in the same lane is stopped;
390 (e) the motorcycle is traveling at a speed of 15 miles per hour or less; and
391 (f) the movement may be made safely.

This further defines what exactly “lane filtering” is:
159 (29) “Lane filtering” means, when operating a motorcycle other than an autocycle, the
160 act of overtaking and passing another vehicle that is stopped in the same direction of travel in
161 the same lane.