Think you know the rules of the road? The Highway Code contains over 300 rules, and some of them might surprise you. From sleeping in your car to splashing pedestrians, here are ten lesser-known UK driving laws that could land you in trouble - even if you've never heard of them.

1. Splashing pedestrians with puddles is illegal

We've all seen it happen - a car ploughs through a puddle and drenches someone on the pavement. Annoying? Yes. But also illegal. Under the Road Traffic Act 1988, deliberately driving through puddles to soak pedestrians counts as 'careless and inconsiderate driving.' You could face a £100 fine and three points on your licence. If it goes to court, fines can reach £5,000. So next time it's raining, show some consideration - it's literally the law.

2. Sleeping in your car while drunk is an offence

Had a few too many and thinking of sleeping it off in your car? Think again. Under Section 5 of the Road Traffic Act 1988, it's illegal to be 'in charge of a motor vehicle' while over the alcohol limit - even if you're fast asleep with no intention of driving. You could face a fine of up to £2,500, ten points on your licence, or even a three-month prison sentence. The safest option after a night out is a taxi or a friend's sofa, not your back seat.

3. Using your phone to pay at a drive-through is illegal

The convenience of contactless payment meets the strict reality of UK phone laws. Under the Road Vehicles (Construction and Use) Regulations, using a hand-held phone while in charge of a vehicle is an offence - and that includes tapping to pay at a drive-through. You could receive six points and a £200 fine. The solution? Use a contactless card, or make sure your engine is off and handbrake on before reaching for your phone.

4. Letting your dog hang out of the window could cost you

Dogs love sticking their heads out of car windows, ears flapping in the breeze. But Rule 57 of the Highway Code states that dogs should be 'suitably restrained' while travelling. If your pet distracts you and causes an incident, you could be charged with driving without due care and attention - potentially facing a fine of up to £5,000 and nine points. A proper dog harness or carrier is the legal (and safer) option.

5. Playing music too loudly can get you in trouble

Love cranking up the volume? Be careful. Rule 148 of the Highway Code warns against distractions including loud music, as it could prevent you hearing sirens or other important sounds. Additionally, Regulation 97 of the Road Vehicles (Construction and Use) Regulations 1986 states you must not use your vehicle in a way that creates 'excessive noise.' Police can - and do - issue fines for stereos that disturb the peace.

6. Driving too slowly is an offence

We all know about speeding, but crawling along well below the limit can also land you in trouble. Under the Road Traffic Act 1988, driving too slowly can be classed as 'careless driving' if it creates a hazard or holds up traffic unnecessarily. This is particularly relevant on motorways where slow-moving vehicles can cause dangerous situations. While there's no specific minimum speed, common sense and awareness of other road users are essential.

7. A dirty number plate can mean a fine

The DVLA takes number plate visibility seriously. Under the Road Vehicles (Display of Registration Marks) Regulations 2001, your plates must be clean and legible at all times. A plate obscured by dirt, snow, or grime can result in a fine of up to £1,000. After muddy drives or bad weather, it's worth giving your plates a quick wipe - it takes seconds and could save you a significant penalty.

8. Eating while driving isn't specifically illegal - but it could still get you fined

There's no law that explicitly bans eating behind the wheel. However, if munching on a sandwich causes you to drive carelessly, you can be prosecuted for driving without due care and attention. The same applies to drinking coffee, applying makeup, or any other activity that takes your focus off the road. The law is less about the activity itself and more about whether it affects your driving.

9. Honking your horn inappropriately is against the rules

Your horn is meant to alert other road users to your presence - not to express frustration at the driver who cut you up. Rule 112 of the Highway Code states you should never sound your horn aggressively, and it's illegal to honk while stationary (unless there's danger) or in a built-up area between 11:30pm and 7am. Using your horn inappropriately could be classed as a breach of the peace.

10. Not clearing snow and ice properly is an offence

On frosty mornings, it's tempting to scrape a small viewing hole and set off. But driving with obscured windows is illegal, and snow left on your roof can slide onto your windscreen or fly off and hit other vehicles. You need clear visibility through all windows and mirrors, and loose snow must be removed. Fines can reach £60 for restricted vision, but if snow from your car causes an accident, the consequences could be far more serious.

Knowledge is power

Most of these laws exist for good reason - they keep everyone safer on our roads. While you're unlikely to be prosecuted for a slightly grubby number plate or a bit of loud music, it's worth knowing where the lines are. The Highway Code is freely available online, and a quick refresher never hurts. After all, ignorance of the law is never a defence.