Everyone knows someone who thinks they are God's gift to the road. A driver who thinks they know it all.

Well, Tim Shallcross, from Carmarthen, probably does know it all.

He's the head of technical policy at the Institute of Advanced Motorists, so it is fair to say he knows his hazards from his headlights.

On that basis, we asked him about some of the annoying things we all see drivers do from time to time and whether they are legal or not. Here's what he came up with.

Tim Shallcross, Head of Technical Policy and Advice at IAM Roadsmart with a Jensen Healey car

Drive too close behind someone?

"Yes, this can be classed as careless driving. It is one of the most common causes of accidents," said Tim. "A third of people in the UK do not realise that tailgating is a finable offence in the UK. It could land you with a fine of £100 and three penalty points. Careless drivers usually tailgate in an attempt to get the driver in front to speed up or move out of the way."

Cut in front of someone and then brake

This is dangerous - if this causes an accident then you could face the force of the law. Tim said: "The most important thing that we keep coming back to is the two second rule. If you keep a suitable distance then you have enough time to stop if a car in front of you slams on the brakes. The two second rule applies to the cars in front and behind you.

"Some people cut in because they don't want to be seen to hog the middle lane."

Hog the middle lane

July 2015 saw the first driver fined for hogging the middle lane and according to Confused.com a third of UK drivers still predominantly use the middle of the road. Tim says: "Middle lane hogging falls into the category of careless driving. However, the practice can be quite subjective. If you have just overtaken someone on a dual carriageway or motorway and then there is another vehicle that you would be pulling out to overtake in a matter of seconds, you may as well stay in that lane."

Part 264 of the Highway Code says: "You should always drive in the left-hand lane when the road ahead is clear. If you are overtaking a number of slower-moving vehicles, you should return to the left-hand lane as soon as you are safely past."

With undertaking being frowned upon in the UK, middle lane drivers can annoy many people.

Tim says: "It effectively reduces the capacity of the motorway by a third with people in the inside lane unable to pull out and overtake."

Leave your lights on full beam at night to dazzle oncoming traffic

This could be considered illegal - it would be driving without due care and attention. Tim said: "The best thing to do is to make sure your lights are adjusted. Not many drivers realise that the more people or more your car is loaded up the more it changes your lights.

"In lots of cars there is a dial next to your lights to adjust the level. Use one extra person as one notch up the dial, and so on as a rough guide. Most new cars have this feature in built to run automatically."

Drive too slowly

This is not an offence unless there is a minimum speed limit. Tim said: "Not many people know this but there is actually a minimum speed limit on the motorway and dual carriage way of 20mph, which seems very low.

"If you are a slow moving vehicle it is advised that you have a flashing amber beacon."

It is actually legal for a mobility scooter to drive on a dual carriageway with a flashing amber beacon.

The minimum speed limit sign is usually a blue circle with white writing.

Tim said: "The best speed limit is the speed you are most comfortable with. Older people may drive at slower speeds because their reactions may be slower, for example."

Hoot or flash at someone to tell them they have done something wrong

Hooting is an offence. Tim said: "You are only meant to use it to declare to other road users 'I am here' not to tell them off."

It is also illegal to sound your horn between the hours of 11.30pm and 7am in built up areas.

However, flashing your headlights to tell someone off is not illegal. Tim said: "Most people use it to tell someone that they are giving way to them, although there is no official meaning. It's quite ambiguous. If you use it to tell someone off it could be misinterpreted as telling someone that you are giving way to them, so it is best used with caution."

Not pulling forward to the front petrol pump

Tim says: "Although this is highly annoying, it's not an offence."

Park across two bays

Yes this is a ticketable offence, even if you pay for both spaces. Tim said: "The issue would lie with the local authority or whoever runs the car park. Most car parks state that you must park within the marked bay. Although sometimes this is hard as cars are getting bigger and bigger nowadays and car park spaces are staying the same size."

Park miles from the kerb or on the pavement

Tim said: "You would have to catch an officer in quite a bad mood to book you for this one. Although it is advised that you don't park more than eight inches from the kerb or you could lose your wing mirror or cause an obstruction."

However, if you park on the kerb on or the pavement it is dependent on what your local authority says. Rules can change from road to road.

Tim advises to "leave room for a pram or wheelchair so as to not be inconsiderate to the most vulnerable members of our society."

Do your make-up in the rear view mirror whilst driving

Tim says: "This is illegal and dangerous. You would be charged with driving without due care and attention if caught."

Change your mind suddenly about which direction you're going in

Tim says: "Whilst this is not illegal it is dangerous. It is always best to continue on your route and find a safe place to change direction later in the journey, rather than changing your mind at the last minute. It could easily cause and accident.

"You should try to avoid making other drivers have to slow down or alter their route because of your mistakes. You are relying on their reactions."

Not thanking someone when they let you through

Tim says: "This should be illegal but it's not. I think thanking people on the road makes the world a nicer place."