There are big stickers in the front and rear windshields on some cars in Northern Ireland. They say either L or R. A college friend who was over for a visit in October asked me what they meant and I had no idea. I happened to see one today while I was waiting for the bus and asked the random stranger who was also waiting what they meant.
The L sticker is for a learner. A learner can apply for a permit as early as three months before his 17th birthday, but it will not be issued until the date of his 17th birthday. Learners must be accompanied by a driver over the age of 21 who has been fully licensed for 3 years and are not allowed to surpass speeds of 45 MPH.
The R sticker is for a restricted license. Once a learner turns 18 and passes his driving test, he is issued a restricted licence, which means he is banned from the motorways for a full year. In fact, he is not allowed to drive over 45 MPH.*
A quick tidbit: The Queen is the only person in the UK who is not required to hold a driver’s license in order to drive, nor are any vehicles personally owned by the Queen subject to numbered plate requirements.**
*All that information can be found here.
**This seems to be common knowledge as Googling that piece of information turns up a wealth of sites, but here’s a reliable source.