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Rules of the road · about 2 min read

Fuel, exhaust and electrical safety

Understand the rule, its conditions and how to apply it

What you will learn

  • Explain the purpose of this rule.
  • Apply the procedure and recognise its limitations.

Purpose and essential terms

Fuel systems carry flammable fuel, wiring carries electrical energy, and exhaust components carry hot gases. Defects can cause fire, burns, exposure to fumes or a loss of safe control. “The engine still runs” is not evidence that the vehicle is roadworthy.

An exhaust silencer controls noise and routes gases away from occupants. Exhaust gases must not leak into the driving cab or passenger compartment, and dense smoke must not obstruct other road users’ view.

Key idea: Fuel systems carry flammable fuel, wiring carries electrical energy, and exhaust components carry hot gases.

How to apply the rule

Before use, look for signs of leaks, damaged or exposed fuel equipment, a missing or ineffective fuel cap, loose batteries and unsafe wiring. Have suspected defects checked by a qualified person instead of improvising repairs near hot or moving components. The fuel system, wiring and battery must be installed, insulated and maintained so they do not create danger.

Switch the engine off before refuelling and follow the filling station’s safety instructions. Do not permit oil or flammable material to drip on the exhaust. Keep the engine covered as required so it is not a source of danger. If fumes enter the passenger area, stop safely and arrange investigation rather than treating an open window as a repair.

Key idea: Do not set off or create an ignition source.

Conditions and easily confused points

Excessive noise and hazardous exhaust smoke are separate concerns: a quiet engine can still leak dangerous gases. A decorative engine drawing cannot establish whether the vehicle is safe; actual inspection matters.

Do not leave an engine running while the vehicle is unattended. This is both a general driving-duty issue and a preventable safety risk.

Key idea: Apply the full rule to the actual vehicle, road and conditions.

Worked road situation

You smell fuel and see a wet patch beneath the parked vehicle.

  1. Do not set off or create an ignition source.
  2. Keep people away from the suspected hazard and follow appropriate emergency guidance.
  3. Have the fuel system checked by qualified assistance before the vehicle is used.

Quick recap

  • Do not set off or create an ignition source.
  • Keep people away from the suspected hazard and follow appropriate emergency guidance.
  • Have the fuel system checked by qualified assistance before the vehicle is used.

Practice questions on fuel, exhaust and electrical safety

1 May exhaust fumes leak into the passenger compartment?

  1. No, the exhaust must be maintained to prevent this
  2. Yes, on a short trip
  3. Yes, with a window open
Show the answer

Answer A: No, the exhaust must be maintained to prevent this

Exhaust gases must not leak into the cab or passenger compartment. Fuel equipment must not be defective or a source of danger. Wiring and the battery must be correctly installed and insulated. Switch the engine off before refuelling.

Memory tip: Prevent fumes, leaks and ignition hazards.

All vehicle codes

2 What should you do with the engine while fuel is being put into the tank?

  1. Switch it off
  2. Leave it idling
  3. Rev it gently
Show the answer

Answer A: Switch it off

Exhaust gases must not leak into the cab or passenger compartment. Fuel equipment must not be defective or a source of danger. Wiring and the battery must be correctly installed and insulated. Switch the engine off before refuelling.

Memory tip: Prevent fumes, leaks and ignition hazards.

All vehicle codes

3 May a vehicle be used with a defective fuel tank that creates danger?

  1. Yes, if fuel is cheap
  2. No
  3. Yes, if the trip is under five kilometres
Show the answer

Answer B: No

Exhaust gases must not leak into the cab or passenger compartment. Fuel equipment must not be defective or a source of danger. Wiring and the battery must be correctly installed and insulated. Switch the engine off before refuelling.

Memory tip: Prevent fumes, leaks and ignition hazards.

All vehicle codes

4 How must electrical wiring and the battery be maintained?

  1. Properly installed, insulated and safe
  2. Uncovered near fuel lines
  3. Loose so they are easy to remove
Show the answer

Answer A: Properly installed, insulated and safe

Exhaust gases must not leak into the cab or passenger compartment. Fuel equipment must not be defective or a source of danger. Wiring and the battery must be correctly installed and insulated. Switch the engine off before refuelling.

Memory tip: Prevent fumes, leaks and ignition hazards.

All vehicle codes

More rules of the road chapters

Sources: NaTIS Rules of the Road, PDF pp. 26–27, 37, sections 6.21–6.23, 6.49, 6.66; iDriving K53 manual, PDF pp. 91–102 (comparison; incomplete text extraction checked against official reference).

AceK53 is an independent study aid based on public road traffic manuals and is not an official test. Always confirm requirements with your driving licence testing centre.