Eco-safe driving in the theory test: smooth driving, gears and idling
Updated •6 min read
Eco-safe driving means planning ahead so you can accelerate, slow down and brake smoothly, using the highest gear that suits the road, and switching off the engine when it is right to. The DVSA's car syllabus also lists removing roof racks and other excess weight when you do not need them (syllabus unit 4).
This page covers what the DVSA syllabus and the Highway Code say about eco-safe driving. Every point below comes from gov.uk.
What the DVSA syllabus asks you to do
The DVSA publishes a free learning to drive a car syllabus. Its unit on driving safely and efficiently says you need to be able to follow the principles of eco-safe driving by:
- removing excess weight, including roof racks or storage, from your vehicle when not needed
- planning well ahead so that you can accelerate, decelerate and brake smoothly and progressively to minimise fuel consumption
- using the highest gear appropriate for the road and traffic conditions
- using cruise control, where and when appropriate
- making appropriate decisions about the use of ancillary equipment
- turning off the engine, when appropriate
The same unit says you should not put eco-driving techniques above safe driving principles, although generally the two approaches support each other. If a question offers a fuel-saving answer that would be less safe, safety wins.
The habits behind it
| Habit | What the syllabus says you should understand |
|---|---|
| Plan ahead | Spot hazards early so you avoid harsh acceleration and braking |
| Smooth controls | Smooth acceleration and minimising unnecessary revving |
| Gears | The benefits of using the highest gear possible, and when to change down to avoid engine labour |
| Engine braking | Appropriate engine braking can benefit fuel consumption and reduce wear and tear |
| Cruise control | How to use it, if fitted, to minimise fuel consumption |
| Air conditioning | Features such as air conditioning or heated windscreens affect fuel consumption |
| Switching off | When it helps to turn the engine off, for example in a queue at a level crossing |
| Stop-start | How automatic engine cut-off systems work, where fitted |
| Weight | Unnecessary equipment or luggage, such as roof top boxes, can increase fuel consumption |
Idling and the Highway Code (rule 123)
Rule 123 says you MUST NOT leave a parked vehicle unattended with the engine running, or leave the engine running unnecessarily while the vehicle is stationary on a public road (gov.uk: rules 103 to 158).
The rule adds that if you are stationary and likely to stay so for more than a couple of minutes, you should apply the parking brake and switch off the engine to reduce emissions and noise pollution. It is permissible to leave the engine running when stationary in traffic or for diagnosing faults. Our level crossings guide covers waiting at a closed crossing.
Tyre pressures
Annex 6 of the Highway Code says tyres MUST be correctly inflated to the manufacturer's specification for the load being carried. It says to check pressures weekly, before your journey, when the tyres are cold (gov.uk: Annex 6).
A 2011 Department for Transport notice on smarter driving says under-inflated tyres are dangerous and also increase fuel consumption. Our tyres and vehicle safety checks guide covers tread depth and the other checks.
Speed, roof boxes and gear changes
The same 2011 DfT notice gives these figures:
- At 85 mph a car uses approximately 25% more fuel than at 70 mph.
- At 70 mph a car uses approximately 10% more fuel than at 60 mph.
- At motorway speeds a roof box can increase fuel consumption by around 25%.
- When accelerating, change up through the gears early, usually by 2,000 rpm.
These are the notice's own figures from 2011, not a current DVSA test standard. Our roof racks and loads guide explains the roof box question in more detail.
Practice questions
These questions are written for this page to test the points above. They are not DVSA questions.
- Which of these saves fuel: harsh braking, planning ahead, or keeping a low gear? Planning ahead, so you can slow down and brake smoothly (DVSA syllabus unit 4).
- You are waiting at a level crossing and the barriers have just come down. What should you consider? Switching off the engine. The syllabus gives a level crossing queue as an example of when this helps.
- How will a roof box you no longer need affect your car? It increases fuel consumption, so remove it when it is not needed (DVSA syllabus unit 4).
- When should you check your tyre pressures? Weekly, before a journey, when the tyres are cold (Highway Code Annex 6).
- Should you choose an eco-driving technique if it makes a manoeuvre less safe? No. The syllabus says not to put eco-driving above safe driving principles.
Practise the rules
Eco-safe questions often sit near stopping distances and vehicle checks in the test. Try the free practice questions to test yourself.
Check what you remember
Start free with the theorytest.ai diagnostic to see whether eco-safe driving is a weak area. theorytest.ai is independent and is not affiliated with the DVSA. Gov.uk does not publish test questions, so we cannot say how many are about eco-safe driving.
Frequently asked questions
What is eco-safe driving?
Driving smoothly and planning ahead to use less fuel, without putting it above safety. The DVSA syllabus lists smooth control, the highest suitable gear, removing excess weight and switching off the engine when appropriate.
Should you switch off your engine in a queue?
If you are stationary and likely to stay so for more than a couple of minutes, you should apply the parking brake and switch off the engine (Highway Code rule 123).
Does a roof box use more fuel?
Yes. The DVSA syllabus says roof top boxes can increase fuel consumption, and a 2011 DfT notice says around 25% at motorway speeds.
Which gear saves the most fuel?
The highest gear appropriate for the road and traffic conditions, changing down when you need to avoid engine labour (DVSA syllabus unit 4).