Air carrier technician reported while taxiing aircraft to the run-up area; they had to stop the aircraft due to ground vehicles crossing in front of the aircraft.

Narrative

While taxiing Aircraft X from the hangar to the run up area ground vehicles passed in front of the aircraft. The aircraft was moving on Taxiway 1 attempting to turn left onto Taxiway 2. The ground vehicles; yes plural; were driving west on the service road heading toward the cargo buildings. The two vehicles did not stop at the clearly marked stop sign; saw the aircraft and continued driving; forcing the aircraft to stop. The vehicles were white in color and belonged to a contract freight company.Visibility at the time was clear; dry; 80 degrees and sunny. Cause: Willful disregard for the rulesLack of situational awarenessDistractionComplacencyFailure to follow instructions (aircraft right of way; stop signs; airport driving rules)Lack of knowledgeSuggestions: This is the second report filed regarding this type of incident this month (See Report XXXX dated Day 0). My manager; Person A; contacted Person B on Day 1; regarding the failure of ground vehicles to yield to aircraft. Still waiting for a reply. Ground vehicles failing to yield to aircraft occurs multiple times per day in this station. Reports like this have been filed by me and my colleagues; complaints made to local management and the airport authority all to no avail. All we get is a shoulder shrug and 'what can we do' answer.Following the 'See something; say something' mantra; I'm saying something AGAIN!When will Company and the ZZZ Airport Authority take these reports seriously? Does it take an actual aircraft/ground vehicle collision?