I actually know about these..
Ive seen them alot in the city and dont know why there on cars...
They are for country people that do not have access to public or other transport to and from work...
You can get them once you have done your 120hrs and 6 month instead of 12 months.
They come with a ****load more restrictions and are really hard to get so im not sure why city people are displaying them, IM assuming they are just faded greenies in the city
My cousin applied for one, he lives an hour from work (boilermaker) and couldnt get one because they said his parents could drive him three... at 3 in the morning..
I hope that is the answer and the laws havent changed since i spoke to him..
If you are ever needing advice about this sort of stuff call the RTA (or your roads authority) tech. help line and ask them. Thats what their there for. Don't bother popping into the RTA office, they really dont know much and will just search for the answer on google and rta's website...