As far as signage on a work vehicle (said vehicle is typically seen in a residential area): It isn’t prohibited, nor is it called out to be required to get a sign permit. It is also distinguished through definitions as not being a prohibited type.
… (E) Portable signs, including, but not limited to: a-or t -frame signs; signs on trailer frames; menu and sandwich board signs; balloon signs; wind signs; umbrellas used for advertising; and, signs attached to or painted on a vehicle parked and visible from the public right-of-way; provided, however, a vehicle which is used in the normal day-to-day operation of the business shall not be considered a portable sign;
New Definition: SECTION 10.02 Sign Types
…(24) VEHICLE SIGN. A sign, painted or otherwise, attached to an operable vehicle that is regularly used and moved, including signs on a truck trailer. A Vehicle Sign does not constitute a Transported Sign.