You’re cruising down a country lane, windows open, with the sunshine blazing; driving in the summer can be a real joy.

But there are quite a few myths and debate around what motorists can and can’t do when the sun’s out, and the effects the weather may have on our cars.

Here we consider a few myths and misconceptions.

Sunny weather means you get less petrol

Some people believe that hot weather can play havoc with the value for money you get for petrol from your local garage.

In fact, many think that the heat causes the petrol in the underground tanks at the forecourt to expand. As a result, later in the day when the petrol has expanded, you’ll get less fuel for the money you hand over. Instead, you should fill up early in the morning when it’s cooler, as you’ll then get more bang for your buck.

In reality, as the AA has pointed out, this is complete cobblers. You get exactly the same amount of fuel whether you fill up at daybreak or at the end of a roasting day.

My dog can hang his head out of the window

We’ve all seen the unadulterated joy that dogs get when you drive along with their heads hanging out of the window.

However, it’s worth remembering that the Highway Code states that all animals should be “suitably restrained” when you’re out on the move.

Am I allowed to drive in flip flops?

With the summer heat, many of us wave goodbye to sweaty trainers and instead prefer to wear flip flops or strappy sandals.

But are you going to get into trouble with the police if you’re caught driving in them, or even barefoot?

The law states that you can have whatever you like on your feet, so long as you are able to operate the controls safely. So, while you’re technically allowed to drive off with flip flops on, it may not be a great idea.

The water in your battery will evaporate

There was a time when drivers needed to keep an eye on water levels in their car batteries, particularly during hot weather.

However, the AA points out that batteries have been effectively sealed up for more than two decades now, meaning that the water in the battery won’t be going anywhere, no matter how warm it gets.

What about the water in the radiator?

Along similar lines, there may be concerns that the summer sun will lead to the water in your car’s radiator to disappear. 

However, as with the battery, modern cars generally come with a sealed cooling system, so it won’t need topping off. 

The AA points out that, if the level of coolant in the radiator does drop sharply, it’s more likely to be due to a leak, so you should take it to your local garage to get it checked.

Hot weather means your tyres wear more

The theory goes that when it’s really hot, there is more friction between your tyre and the road, and, as a result, the tyre will wear out more quickly.

This is not actually true, though. Regular tyres are designed to work across a wide range of temperatures, so even as the weather heats up, the air pressure in the tyre will reduce just how much of the tread is in contact with the road.

That said, winter tyres - as the name suggests - aren’t designed to deal so well with rising temperatures, so they are likely to wear more quickly when it’s warm.

Of course it’s also a good idea to regularly check the condition of your tyres, regardless of what the weather’s like, to reduce the chances of suffering a blowout.

Is it illegal to eat or drink while driving?

There seems to be a lot of confusion among motorists over whether they are allowed to drink or eat something behind the wheel.

While it’s not illegal to do either, you can be pulled up for careless driving if you are not fully in control of the vehicle, due to the fact that you’re eating or drinking.

That said, it’s still a smart move to make sure you have some water with you in the car if the weather is scorching. Researchers from Loughborough University found that even mild dehydration is equivalent to being over the drink driving limit when it comes to errors that drivers make.

To read more about road safety go to Solved.