From the Salt Lake County Poll Worker Manual, page 48:
Campaigning or other activities that interfere with voting or influence voters is prohibited. Ask the offenders politely to stop or refrain from their activities. If the activity does not cease, call the Elections Division. Any threatening or dangerous behavior should be immediately reported to local law enforcement first, then to the Elections Division. Electioneering includes oral or written attempts to persuade voters to refrain from voting or to vote for or against a candidate or issue. No electioneering or campaigning is allowed within 150 feet of the polling place.
And that truck is definitely less than 150 feet from the polling place(the building right behind the truck).
To be fair, the truck was removed by the time we left our polling place.