Driver Skills · Ireland

Coasting — the good kind, the bad kind, and why your driving test cares

"Coasting" means two opposite things in driving. One is a marked fault on the Irish driving test. The other is one of the most valuable skills in advanced and eco-driving. This guide separates them — using the RSA marking guide, Roadcraft and published research.

📅 Updated June 2026🚗 Driver Skills⏱ 7 min read

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What Coasting Is — and Why It Matters

One word, two completely different driving behaviours.

In the strict sense used by driving examiners, coasting means the wheels are disconnected from the engine while the car is moving — either because the gearbox is in neutral or because the clutch pedal is held down. The UK's Official Highway Code defines it exactly that way: "a vehicle travelling in neutral or with the clutch pressed down" (Rule 122).

But in eco-driving and advanced driving, "coasting" is often used loosely to mean something different and entirely positive: lifting off the accelerator early and letting the car lose speed while still in gear. The engine stays connected, you keep full control — and on a modern engine you burn no fuel at all while doing it.

Why it matters: the difference between the two affects your control of the car, your brakes, your fuel bill — and your driving test result. The RSA's official test marking guidelines list coasting, in both its clutch and neutral forms, as a recordable Vehicle Control fault.

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Bad Coasting, Defined

The two forms examiners watch for — straight from the RSA marking guide.

Clutch coasting

Driving with the clutch pedal pressed down for a prolonged distance — for example, holding the clutch in from 100 metres out while rolling up to a red light
The RSA marking guide describes it as a clutch fault: "coasting, i.e. driving for a prolonged distance with the pedal pressed in"
Common in nervous learners who fear stalling — the clutch goes down far too early "to be safe"

Neutral coasting

Slipping the gearbox into neutral while the car is still moving — typically rolling downhill or toward a junction "to save fuel"
The RSA marking guide lists it as a gears fault: "coasting, i.e. driving for some distance in neutral"
Also applies to automatics — selecting N while moving disconnects the drive in exactly the same way

On test day: both forms are recorded under Vehicle Control. Like any repeated Grade 2 fault, accumulated coasting faults can contribute to a failed test — and they tell the examiner something deeper: the driver is giving away control of the car when they need it most.

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The Risks of Bad Coasting

The Highway Code's list — and what each item means in practice.

Rule 122 of the Official Highway Code spells out why coasting "can reduce driver control":

Engine braking is eliminated

With the wheels disconnected, the engine can no longer help slow the car. Every bit of speed control now depends on the footbrake alone.

Speed downhill increases quickly

A coasting car on a descent is a free-rolling mass. Without engine resistance it accelerates faster than drivers expect — and the longer the hill, the worse it gets.

Heavy footbrake use can reduce its effectiveness

Continuous braking on a long descent heats the brakes and can cause fade — exactly why heavy vehicles carry retarders to provide additional engine braking on hills (Roadcraft). A coasting driver throws that protection away.

Steering response is affected

Particularly on bends and corners. Drive through the wheels helps stabilise the car; a freewheeling car responds differently just when precision matters most.

It may be harder to select the right gear when needed

If a hazard develops mid-coast, you must find the correct gear for your (changing) speed before you can drive out of trouble — a delay you may not have.

And if the engine stalls while coasting: after a few pedal applications the brake servo's vacuum assistance is used up and the pedal becomes very heavy, while power steering assistance is lost too. A stall at speed in neutral turns a routine slope into an emergency.

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Good Coasting Explained

Deceleration in gear — what Roadcraft calls acceleration sense and engine braking.

The skilled version of coasting is simple: see the need to slow down early, lift off the accelerator, and stay in gear. Roadcraft — the police driver's handbook — describes the mechanism: "When you release the accelerator, the engine slows and through engine compression exerts a slowing force on the wheels. This causes the engine to act as a brake, reducing road speed smoothly and gradually with little wear to the vehicle."

What you gain

Control — the car remains driven; steering, stability and the option to accelerate are all preserved
Free braking — speed bleeds off with "little wear to the vehicle" (Roadcraft), saving pads and discs
Zero fuel — modern engines cut fuel entirely on a trailing throttle in gear (see the technical section)
Grip protection — Roadcraft notes engine braking "allows you to lose speed in conditions where normal braking might lock the wheels — for example, on slippery roads"

The supporting skill: anticipation

Good coasting is impossible without looking far ahead — you need to spot the red light, queue or bend early enough to use it
Roadcraft calls this acceleration sense: "Use acceleration sense to vary your road speed without unnecessary braking"
The lower the gear, the stronger the engine's slowing effect — block changing down adds braking when you need more of it
In EVs and many hybrids the same lift-off triggers regenerative braking — slowing the car while recharging the battery (Roadcraft 2025)

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Practical Examples

The same three situations, handled badly and well.

Situation	Bad coasting	Good technique
Approaching red lights	Clutch down 100 m out, rolling in on the footbrake alone	Lift off early, stay in gear and let engine braking do the work; clutch down only in the last car lengths before stopping
Slowing for a bend	Neutral or clutch down into the bend — reduced steering response exactly where the Highway Code warns about it	Lose speed in gear before the bend, then a steady throttle through it — Roadcraft: use the accelerator to maintain a steady speed when you enter a bend
Descending a long hill	Neutral "to save fuel" — speed builds, brakes overheat, control shrinks	Select a lower gear and let the engine hold the speed — the same principle as the retarders fitted to trucks and buses for descents

Professional standard: the UK Department for Transport's SAFED programme for HGV drivers grades a driver as unsatisfactory when "the clutch was disengaged too early causing the vehicle to coast" — and the IRU's eco-driving guidance for professional drivers is explicit: use engine braking to reduce speed when approaching traffic lights, and apply the brakes only to bring the vehicle to a standstill.

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The Technical Bit: Why In-Gear Uses No Fuel

Deceleration fuel cut-off — the fact that settles the fuel argument.

Virtually every fuel-injected car built since the 1990s has deceleration fuel cut-off: when you lift fully off the accelerator while in gear above idle speed, the engine management system stops injecting fuel completely. The wheels keep the engine turning, so it needs none. Fuel consumption while decelerating in gear is effectively zero.

Put the car in neutral, and the picture reverses: the engine is no longer driven by the wheels, so it must inject fuel to keep itself idling — all the way down the hill. Neutral coasting doesn't just cost control; on a modern engine it costs fuel too.

Safety systems prefer a driven car: the brake servo and (on many cars) the power steering pump are engine-driven; engine braking protects grip where harsh braking might lock wheels (Roadcraft); and in EVs the entire regenerative braking system depends on the wheels staying connected to the motor. Modern vehicle design assumes the drivetrain is engaged — coasting works against it.

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Misconceptions

Old habits that research and modern engineering have overtaken.

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"Coasting in neutral saves fuel"

True for carburettor engines decades ago; false since fuel injection. In gear with your foot off the accelerator the engine burns nothing; in neutral it idles and burns fuel. Research interviews still find drivers reporting strategies like "use momentum and gravity, e.g. coasting, declutching down hills" (McIlroy & Stanton) — the instinct to use momentum is right, but the gear lever is the wrong tool: stay in gear and lift off instead.

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"Coasting is gentler and safer"

The Highway Code lists the opposite: less control, faster downhill speeds, weaker steering response and overworked brakes. Smoothness comes from anticipation in gear, not from disconnecting the engine.

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"It doesn't apply to automatics"

Selecting N while moving is the same fault with the same risks — and most manufacturers warn against it. In an automatic, good coasting is identical: lift off early and let the transmission and engine slow the car.

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"Pressing the clutch early prevents stalling, so it's good practice"

A car slowing in gear above idle speed will not stall. The clutch needs to go down only in roughly the last one to two car lengths before stopping (or when changing gear). Earlier than that is coasting — and it's marked.

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What the Experts and the Research Say

A consistent message across testing, police driving and academia.

RSA Driving Test Marking Guidelines: coasting — clutch held "for a prolonged distance" or "driving for some distance in neutral" — is a recordable Vehicle Control fault on the Irish driving test.
The Official Highway Code (Rule 122): coasting "can reduce driver control" — eliminating engine braking, increasing downhill speed, reducing footbrake effectiveness and affecting steering response.
Roadcraft (2025): engine braking reduces speed "smoothly and gradually with little wear to the vehicle", is strongest in lower gears, and protects grip on slippery roads and long descents; acceleration sense lets you vary speed "without unnecessary braking".
SAFED for HGV (UK Dept. for Transport): early clutch disengagement causing the vehicle to coast is graded unsatisfactory in professional driver assessment.
IRU Eco-Driving Coach: every use of the brakes wastes energy — use engine braking when approaching traffic lights and brake only to come to a standstill.
McIlroy & Stanton, Eco-Driving: From Strategies to Interfaces: in simulator studies, drivers given eco-driving feedback showed "significantly greater coasting distances when approaching slowing events" — earlier, longer lift-off (in gear) is one of the two behaviours the research identifies as most significant in eco-driving, alongside smoother acceleration.

The common thread: every authority separates the momentum skill (excellent) from the disconnection habit (faulted). Use the car's momentum deliberately — but keep the engine connected while you do it.

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Closing Tips — Coasting Done Right

The habits to build, in one list.

Do

Look well ahead and lift off the accelerator early when you see a reason to slow
Stay in gear while you lose speed — let engine braking work for you
Change down for long descents and let the engine hold your speed
Press the clutch only in the final car lengths before stopping, or briefly to change gear
In an EV or hybrid, use lift-off regenerative braking the same way

Don't

Roll in neutral — downhill, to junctions, or anywhere else
Hold the clutch down on the approach to hazards "just in case"
Ride the footbrake down long hills while the gearbox does nothing
Coast into bends — slow in gear first, steady throttle through
Assume the old "neutral saves fuel" advice survived fuel injection — it didn't

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Sources & References

📋 RSA — Driving Test Marking Guidelines: Vehicle Control faults (clutch and gears — coasting)
📘 The Official Highway Code (UK) — Rule 122: Coasting
📘 Roadcraft: The Police Driver's Handbook (The Police Foundation, 2025) — engine braking, acceleration sense, retarders
📘 SAFED for HGVs — Safe and Fuel Efficient Driving (UK Department for Transport) — clutch control assessment standard
📘 IRU — The Eco-Driving Coach (International Road Transport Union)
📊 McIlroy, R.C. & Stanton, N.A. — Eco-Driving: From Strategies to Interfaces (CRC Press) — coasting distances and eco-driving feedback studies