You give them a blast of the horn to show your disapproval – that’s a $319 fine.

That guy who turned on their indicator too late – they’re liable for a $377 fine and three demerit points.

Chances are high you weren’t aware either action was actually illegal. When it comes to the horn, its use for anything other than to warn road users or animals of your approach is illegal.

As drivers, we study the road rules to get our licence and probably never look at them again.

Well, unless we hit 85 and want to keep driving – then we need to pass a driving test every year.

It’s guaranteed that a flick through the list of general driving offences (which is 13 A4 pages of small type) will surprise you. 

For example, resting your arm on the window ledge while driving? That’s a $319 fine and three demerit points.

“This rule ensures safety of vehicle occupants and surrounding road users,” said Executive Director Centre for Road Safety Bernard Carlon.

“For example, if a vehicle occupant has a limb outside of their vehicle, there’s a chance they could injure themselves or another road user. 

If you leave your car unlocked and unattended, you’re risking a $106 fine and two points on your licence.

“All drivers who park a vehicle on a road must immediately lock all vehicle doors if they are going to be more than three metres away from their vehicle,” Mr Carlon said.

Other little-known fines are: a sound system “emitting offensive noise” ($200 and two points), speeding up when being overtaken ($319 and three points) and flashing your lights to warn drivers of a police operation ($106 and one point). 

There are also some odd ones; the $177 fine for splashing mud on people waiting for a bus, the $319 fine for riding in the boot of a car, the $71 for riding a bicycle “furiously” or the $71 fine if you try to make a few bucks by cleaning windshields at traffic lights.

Also, while you’re allowed to drive if you’re under the .05 legal limit for alcohol, you cannot drink and drive at the same time, regardless of blood-alcohol level.

Doing so will cost you $319 and three points.

However, there are also things you may have thought illegal but aren’t.

For instance, you don't need to give way to pedestrians at a roundabout and riding a bicycle on a footpath is okay if you’re supervising a child under 12.

Finally, while the law bans mobile phone use while driving, emergency services (such as police) are exempt from this rule.