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8 common theory test mistakes

And how to avoid them

Introduced in 1996, the driving theory test is the first step to getting your license. But 51.3% of learner drivers aren’t able to correctly answer the necessary number of questions to pass, currently 43 out of 50 1

So we asked qualified drivers to answer questions from the theory test, which revealed  it’s not only novice drivers who struggle with the multiple choice exam. 

So if the nerves are getting to you because your test is imminent or you simply want a refresh, we’ve answered the 8 questions people get wrong most often to get your road knowledge up-to-scratch. Tony Flory – Young Driver Specialist at Road Safety GB – also gives us his expert opinion on how these common mistakes can be avoided, both during the test, and on the road.

When is it okay to undertake a vehicle?

Undertaking a vehicle is allowed:

  • in slow-moving traffic queues, when the vehicles in the right-hand lane are moving more slowly
  • when the vehicle in front is signalling to turn right
  • when you’re in a one way street

Although it’s legal to pass on the left in these situations, Flory emphasises that “this mustn’t be used to excuse drivers who are planning to change to outer lanes simply to avoid queuing and gain advantage.” Flory follows this point by stating that, “in any event, undertaking must only be carried out with caution and usually reduced speed as drivers in outer lanes may not expect vehicles to arrive alongside from the left.”

Less than 1 in 3 (27%) people got this one right, making it the most commonly failed question. This may be due to the fact that as soon as we hear the word ‘undertaking’, most of us immediately assume this isn’t allowed, in any circumstance.

In good conditions, what's the typical stopping distance at 70 mph?

In normal conditions, the stopping distance at 70mph is 96 meters (315 feet), or 24 car lengths.

There are a variety of other factors, however, that can affect stopping distance – such as weather, road and car condition and ultimately your reaction time.

The main reason why so many (72%) motorists got this question wrong is that when learning about stopping distances, “the information is usually in table form which is very easy to forget when questions about stopping distances are no longer being asked.”

How to calculate stopping distance

Unless you’re a math whiz, calculating stopping distances at various speeds can be tricky.

Starting at 20mph, all you need to do to find your approximate stopping distance in feet is multiply your speed by 2, and then by increments of 0.5 every 10mph after that.

You're driving down a long, steep hill. You suddenly notice that your brakes aren't working as well as normal. What's the usual cause of this?

When driving down a long, steep hill, the most likely reason why your brakes aren’t working as well as normal is that they’ve overheated.

Imagine how scary it would be if your brakes suddenly stopped working when you needed them most. Fortunately, thanks to changed and improved brake friction materials and design, this isn’t quite the issue it used to be – but “glazing of brake discs and drums caused by prolonged/heavy braking can still occur.”

Flory indicates that, “very often, the only course of action after such an overheating event is to replace the burned brake linings,” so knowing how to prevent this can be extremely important for both your safety and wallet.

How to prevent your brakes overheating

One way “to avoid the problem is by maintaining a low down-hill speed by adopting a lower gear, which will allow the driver to release the footbrake from time to time to allow them to cool.” “As a general guideline,” suggests Flory, “use the same gear going down a hill as you might going up the same hill. Drivers on very long descents should also consider stopping/parking where it’s safe, so that the brakes can cool.”

At a pelican crossing, what must you do when the amber light is flashing?

The Highway Code states that when the amber light is flashing at a pelican crossing – a signal-controlled crossing where a flashing amber light follows red – you must give way to pedestrians already on the crossing.

“Very simply” says Flory, “all lights and combinations mean stop except for green, which isn’t an order to ‘go’, it’s a permission to continue if safe to do so.”

Both red and amber and combinations are orders to ‘Stop’ until it is both ‘Green’ and ‘Safe’.

You take the wrong route and find you're on a one-way street. What should you do?

Although your instinct may tell you to simply turn around or reverse, if you find yourself in this awkward situation you should always continue to the end of the road.

Every driver must expect to go the wrong way from time to time. Don’t panic and don’t reverse. There will always be a safe and legal way back.

Why are the yellow lines painted across the road?

The yellow lines painted across the road are to make you aware of your speed; they’ll often be painted as a group of single lines first, followed by a group of double lines, followed by a group of triple lines as the new lower speed limit is approached.

“Usually found on the approach to a speed limit reduction, the lines are often thick enough to feel through the car and designed to be seen and felt,” says Flory, “drivers who see them in advance can save some discomfort by lowering speed in good time.”

As well as holding a full licence, which of the below options is also a requirement for those supervising learner drivers?

By law, in addition to holding a full licence for 3 years or more (and not be subject to a ban), you must also be at least 21 years old in order to supervise a learner driver.

Flory suggests that “some drivers don’t seem to realise that as the supervisor of a ‘Learner’, they’re subject to the law as if they were driving. For example, awake, sober and alert.” Additionally, Flory reminds us that “the car must be properly insured, taxed and MOT’d and display ‘L’ plates.”

You're towing a small trailer on a busy three-lane motorway. What must you do if all the lanes are open?

According to motorway rules and regulations, you must only use the left-hand and centre lanes when towing; any vehicle which is towing a trailer of any size is not allowed in the outside lane of a motorway if it has three or more lanes. This rule does not apply to a motorway that only has two lanes.

Trailer or not, basic rule is drive in the first available lane from the left unless overtaking.

That’s it, the 8 most commonly failed theory test questions. We all make mistakes from time to time, but remembering the rules of the road can sometimes be the difference between being involved in a collision and reaching your destinations safely.

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