Speed and Stopping Distance is one of the most crucial Highway Code topics for UK learner drivers and instructors.
Below is a complete One Time Pass Driving School guide to Speed and Stopping Distance, including formulas, tables, graph, and safety principles.

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🚗 SPEED & STOPPING DISTANCE — UK HIGHWAY CODE GUIDE

(One Time Pass Driving School — Highway Code Learning Series)

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🧮 1️⃣ The Formula

Thinking Distance + Braking Distance = Total Stopping Distance 

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🧠 2️⃣ Thinking Distance

The distance your car travels from the moment you see a hazard to the moment you start to press the brake.

It depends on:

• Your reaction time (usually 1 second average).
• Your speed.
• Concentration level (tiredness, distractions, alcohol, drugs, mobile use).

🧭 Approximation formula:

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🛑 3️⃣ Braking Distance

The distance your car travels after you press the brake until it fully stops.

It depends on:

• Tyre condition and tread depth.
• Road surface (wet, icy, gravelly).
• Brake condition.
• Weight/load in the vehicle.

🧭 Approximation formula:

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📏 4️⃣ Full Stopping Distance Table (UK Highway Code)

Speed (mph)	Thinking Distance (m)	Braking Distance (m)	Total Stopping Distance (m)	Equivalent Car Lengths
20	6	6	12	~3
30	9	14	23	~6
40	12	24	36	~9
50	15	38	53	~13
60	18	55	73	~18
70	21	75	96	~24

⚠️ All based on dry road, good tyres, and an alert driver.

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📊 5️⃣ Infographic Table

🏎️ Speed	⏱️ Thinking Distance	🛑 Braking Distance	📏 Total Stopping	🧭 Key Reminder
20 mph	6 m	6 m	12 m	Town traffic / schools
30 mph	9 m	14 m	23 m	Built-up areas
40 mph	12 m	24 m	36 m	Rural roads
50 mph	15 m	38 m	53 m	A-roads
60 mph	18 m	55 m	73 m	Single carriageways
70 mph	21 m	75 m	96 m	Dual carriageways & motorways

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📈 6️⃣ Graph — Speed vs Stopping Distance

Speed (mph)	Stopping Distance (m)
20	12
30	23
40	36
50	53
60	73
70	96

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⚙️ 7️⃣ What Affects Stopping Distance

Factor	Effect
Wet / icy road	Increases braking distance × 2–10
Worn tyres or brakes	Reduces grip → longer stop
Heavy load	Increases braking distance
Road gradient	Uphill shortens, downhill lengthens
Poor visibility	Delays reaction time

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🧠 8️⃣ What Affects Thinking & Braking Distance

Thinking Distance (mental)	Braking Distance (mechanical)
Fatigue	Tyre pressure / condition
Alcohol / drugs	Road surface (wet, icy)
Distraction (phone, talking)	Brake pad wear
Inexperience / overconfidence	Vehicle weight or trailer load
Poor eyesight	Speed itself (energy = ½ mv²)

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🕹️ 9️⃣ Applying the Routine Before a Junction

Just like the Mirror–Signal–Manoeuvre routine, you should start preparing for your stop or turn in good time.

Speed	Begin slowing / mirror routine before junction
20–30 mph	~30–45 m (about 3–5 seconds)
40–50 mph	~60–75 m (about 6–7 seconds)
60–70 mph	~100 m+ (8–10 seconds)

✅ Golden Rule:

“Check mirrors before changing speed — brake progressively and early, never sharply.”

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🧍‍♂️ 10️⃣ How to Stay Safe on UK Roads

1. Keep a safe following distance — use the “two-second rule” (double in wet weather and ten times the normal weather condition on Icy Roads).
2. Plan ahead — look well beyond the car in front.
3. Avoid distractions — no mobile use or fiddling with screens.
4. Stay visible — use dipped headlights when needed.
5. Adapt your speed — match road, traffic, and weather conditions.
6. Check mirrors before every change of speed, direction, or signal.
7. Drive smoothly — avoid harsh acceleration or braking.
8. Respect speed limits — they are the maximum, not a target.

Always Make Good Use Of Your Mirrors.