2166 reviews
Driving Theory 4 All
Home Free Theory Test Practice Resources Take FREE Practice Theory Tests Take FREE HGV / LGV Practice Theory Test Question 28

Incorrect!

You have to drive onto a muddy building site. Why should you switch on your diff-lock?

To make your steering lighter
To improve your fuel consumption
You selected this answer
To increase your engine power
To make the wheels less likely to spin
Correct answer

DVSA theory test explanation

Engaging the diff-lock means that the driven wheels are locked together. This reduces the likelihood of wheel spin. Remember to switch off the diff-lock as soon as you're on firm ground again, otherwise you could damage the transmission.

Previous HGV / LGV theory test question Previous
Next HGV / LGV theory test question Next

Want to pass your DVSA driving theory test first time?

Whether you’re ready to book or still want to revise, choose the option that suits you best...

Full access to our AI-powered theory test app, your DVSA theory test booking and unlimited re-sits if you don’t pass first time

Book your theory test with unlimited re-sits

Already got your DVSA driving theory test date and want to make sure you’re fully prepared?

Get test-ready with our AI-powered theory test app

Want more HGV / LGV theory test questions and answers?

Tap the Next HGV / LGV theory test question button to see the next HGV / LGV theory test question, or pick a few random questions from the list below to mix up your practice.

Not what you were looking for?
Find out what we offer for every DVSA theory test by selecting the theory test you want to prepare for.
Car
Theory Test
Motorcycle
Theory Test
ADI
Part 1
Theory Test
LGV
Theory Test
(part 1a and 1b)
LGV CPC
Module 2
Theory Test
PCV
Theory Test
(part 1a and 1b)
PCV CPC
Module 2
Theory Test

Industry leading reviews from 2166 verified buyers...

Read More Reviews
Driving Theory 4 All Reviews
Driving Theory 4 All on X

Keep up to date with us on social media...

Do you have a theory test date booked with the DVSA that you want to change? 🚗📅 Changing or cancelling a DVSA theory test date is a straightforward process. This article gives you the steps to reschedule your theory test booking 👇 https://t.co/hsWfeUOYIZ #changetheorytest https://t.co/0uumcTNWUU
2 days ago
What is the 2026 DVSA theory test pass mark? ✍️🚗 Find out everything you need to know about the theory test pass marks and pass rates for the DVSA driving theory test 👇 https://t.co/8oP2dtoPgl #theorytest #drivingtheorytest #theorytestpassmark #booktheorytest https://t.co/g1tz97LUEy
3 days ago
What should you do if your ABS light stays on? This is a question you will need to be able to answer for your UK driving theory test. Read our handy article to find out more https://t.co/rxH1U4ZrX6 https://t.co/IMc7OSHJHp
4 days ago
If you see a ford warning road sign you will need to keep an eye out for water on the road 🌊 Learn more about the ford warning road sign as well as the other 900+ road signs you need to know to pass your DVSA theory test 👇 https://t.co/99DHIDtKHx https://t.co/k1BrST00hW
5 days ago
Are you looking to pass your driving theory test? 😃 Our AI-powered driving theory test app can help you pass your theory test quicker than you thought possible 😍 Start your driving theory test practice free trial now 👇 https://t.co/t4xIylQKpR https://t.co/cBf1YgM17m
5 days ago
If you're looking to pass your DVSA theory test in 2026, you will need to ensure you know your road signs. 👀 Why not, try using the UK Road Signs section of our website to assist your learning, COMPLETELY FREE! 👇 https://t.co/RpL68eHwlB https://t.co/qkEMndMePJ
6 days ago
Looking for a quick and easy way to practice for your DVSA car theory test and PASS first time? ⚡ Get instant online access to the latest DVSA revision questions and CGI hazard perception clips, exclusive tutorial videos, plus much more 👇 https://t.co/Y2wHD1ZtFh #theorytest https://t.co/wmhYVS1vYY
6 days ago
Need to find your theory test centre for your theory test in 2026? 👀 Use our useful tool to find the DVSA driving test centre closest to you 👇 https://t.co/LcLUW7uqHk https://t.co/7pYNuhDK8b
1 week ago
Looking to pass your driving theory test in 2026? 😍 Hazard Perception is an important part of the theory test. 👀 Take a free hazard perception test now and get ready to pass your theory test first time. 👇 https://t.co/WhqbFkSkWa https://t.co/i86jOITowU
1 week ago
What is the 2026 DVSA theory test pass mark? ✍️🚗 Find out everything you need to know about the theory test pass marks and pass rates for the DVSA driving theory test 👇 https://t.co/8oP2dtoPgl #theorytest #drivingtheorytest #theorytestpassmark #booktheorytest https://t.co/CRJv3x0ja0
1 week ago
Happy New Year from everyone here at Driving Theory 4 All! 🎄🎁 If you're looking to pass your driving theory test in 2026 and want help learning everything you need, give us a try 👇 https://t.co/vv7cJmT620 #theorytest https://t.co/mVOA0j6SbY
1 week ago
Looking for a quick and easy way to practice for your DVSA car theory test and PASS first time? ⚡ Get instant online access to the latest DVSA revision questions and CGI hazard perception clips, exclusive tutorial videos, plus much more 👇 https://t.co/Y2wHD1ZtFh #theorytest https://t.co/R0Sf8lb6cw
1 week ago
Do you need to head to your local DVSA theory test centre to take your driving theory test? 👀 Are you looking for assistance in booking your car theory test? 😀 We can help. We will book your theory test and even offer FREE re-sits! 👇 https://t.co/Smc2AfVxll https://t.co/zubeXsOkaN
1 week ago
Do you have a theory test date booked with the DVSA that you want to change? 🚗📅 Changing or cancelling a DVSA theory test date is a straightforward process. This article gives you the steps to reschedule your theory test booking 👇 https://t.co/hsWfeUOYIZ #changetheorytest https://t.co/sTdXq3B0Q9
1 week ago
Do you have a theory test date booked with the DVSA that you want to change? 🚗📅 Changing or cancelling a DVSA theory test date is a straightforward process. This article gives you the steps to reschedule your theory test booking 👇 https://t.co/hsWfeUOYIZ #changetheorytest https://t.co/HojslWablH
2 weeks ago
Merry Christmas from everyone here at Driving Theory 4 All! 🎄🎁 If you're looking to pass your driving theory test in 2026 and want help learning everything you need, give us a try 👇 https://t.co/scPqZ2czwV #drivingtheorytest #theorytest #cartheorytest https://t.co/RMTGH6NvB4
2 weeks ago
What is a puffin crossing? 🚦 A puffin crossing is a pedestrian crossing that prioritises the safety of pedestrians. Find out everything you need to know here 👇 https://t.co/HSqCXTdB4b #puffincrossing #theorytest #booktheorytest #highwaycode #roadsafety https://t.co/4qc33ezNOx
2 weeks ago
Want to try some FREE mock theory tests to get ready to pass your DVSA theory test in 2026? 👀 Whether you're taking your car theory test or your ADI Part 1 theory test we've got you covered! 👇 https://t.co/7il2jIpX4r https://t.co/E9a1MRIWGO
2 weeks ago
Looking to pass your theory test in 2026? 👀 Our Free Theory Test Practice resources page can help you by providing plenty of FREE revision assistance. 😀 Check out our free theory test practice resources now 👇 https://t.co/66v9hVuK0d https://t.co/h5QgNew5D1
2 weeks ago
🐕‍🦺 Highway Code Rule 56 🐕‍🦺 You shouldn't allow your dog to go onto the road. Keep the lead short when walking your dog on the pavement or road. Learn everything you need to pass your car theory test 👇 https://t.co/vSZBbqjSSa #cartheorytest #theorytest #highwaycode https://t.co/wEQ53NmIDT
3 weeks ago