This is what happens for someone I know working in a different govt ministry. If she or her team are required to make an official visit/inspection or attend a meeting or conference, an official pickup or van with driver is provided. These can range in distance from inside the provincial city to 4 or 5 provinces away. If no official vehicle is available and she has to drive her own vehicle she receives travel allowance cash based on distance from her admin office. I cant see why immigration works differently.