6.3 Following & Stopping Distance

Space is a life-support system

Speed limits tell you how fast you may go. Following distance tells you whether you can still stop without hitting the vehicle ahead when that vehicle brakes hard. The Nigerian Highway Code (Part Two, Section XI) opens with a simple command: never get too close to the vehicle in front. Leave enough space so you can stop safely if the vehicle ahead slows or stops suddenly. The safe rule is never to get closer than the overall stopping distance shown in the Code’s table. On wet roads the gap should be much more. If an overtaking vehicle fills the gap in front of you, slow down and rebuild space.

Quick Answer: Overall stopping distance (approximate, dry idealised table) rises from 10 m at 20 km/h to 92 m at 100 km/h. Use the two-second rule, reciting “Staying too close or trailing for safety.” If you reach the marker before finishing, you are too close. Wise drivers use three seconds (“Playing it Safe!”) and, in bad weather, four seconds (“Safer and Sane”). Heavier vehicles need more room and can destroy light cars in a collision — avoid “no contest” encounters with trailers and buses.

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Thinking distance + braking distance = overall stopping distance

The Code splits stopping into two parts:

Both components increase with speed. Thinking distance grows because you cover more road per second while your brain reacts. Braking distance grows even faster as kinetic energy rises. That is why a jump from 60 to 100 km/h is not a small change in required gap.

Official Highway Code approximate table

Memorise at least the overall column; strong candidates also know the split.

NOTE from the Code: Stopping distance increases greatly with wet and slippery roads, poor brakes, bad tyres, and tired drivers with low reaction time. Distances given are approximate.

How to use the table on the CBT

• If a stem asks overall distance at 80 km/h, answer 72 m (not 50, which is only braking, and not 22, which is thinking).
• If a stem asks what happens on a wet road, choose much more gap than the dry table — the Code says so directly.
• If a stem mixes tyres, brakes, fatigue, recognise each as a distance multiplier, not a reason to follow closer.

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The two-second rule (and longer)

Tables are hard to visualise at speed. The Code therefore teaches a time-gap method.

Two-second rule procedure

1. Choose a stationary object ahead near or above the road — road sign, tree, overpass, or any convenient fixed marker.
2. When the vehicle ahead passes that object, start reciting slowly:
   “Staying too close or trailing for safety.”
3. If you reach the same object before you finish the phrase, you are following too closely. Slow down and let the gap open.

Why that phrase?

The Code notes it takes approximately two seconds to recite any carefully chosen three-word-group phrase. Do not pick very short words that you can gabble in under a second — that cheats the test and your safety.

Three-second and four-second extensions

Memorise the jingles exactly for exam recognition items. Paraphrases are fine in real driving; CBT stems may quote the Code wording.

Relative speed note

The Code adds: the safe gap depends on the relative speed between the two vehicles. If you are catching up quickly, the time gap shrinks even if the metre gap looked “okay” a moment ago. Rebuild space before you need emergency braking.

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Wet roads, night, and other multipliers

Wet roads need much more gap — this is a direct Code rule, not optional advice. Water reduces tyre grip; braking distance lengthens sharply. Combine rain with:

• Painted lines and metal plates that become skating surfaces.
• Oil films after the first minutes of rain.
• Reduced visibility that increases thinking time.

Night and harmattan dust lengthen the time to identify a brake-light event. Fatigue slows reaction (thinking distance up). Overloaded vehicles and poor brakes/tyres lengthen braking distance. The parade checks from Chapter 3 exist partly so braking equipment is ready when the gap is tested for real.

If someone cuts into your gap

The Code’s instruction is practical: when an overtaking vehicle fills the gap in front of you, slow down. Do not accelerate to “punish” them or ride their bumper. Rebuild the two-to-four-second cushion.

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Heavier vehicles: control limits and weight disparity

The Code warns that smaller vehicles face greater risk in collisions with larger vehicles such as articulated lorries (trailers), tankers, luxury buses, and other heavy trucks and vans. Key points:

• Heavier vehicles are more difficult to control.
• Their ability to stop or manoeuvre is greatly hampered by the weight of load conveyed.
• Therefore you must give them extra space — both when following them and when sharing lanes around them.

Avoid the “no contest” encounter

The Code urges drivers to note the large weight differential between cars and heavy trucks/buses:

• A typical laden trailer may weigh about 30 to 40 metric tonnes.
• A fully loaded luxury bus may weigh about 10 to 20 metric tonnes.

It states a scientific comparison for intuition: a trailer travelling at 50 km/h can have a destructive effect comparable to a Peugeot saloon travelling at 250 km/h in the Code’s illustration of impact severity. That is why smaller vehicles are often shredded and occupants mangled in such collisions. Exam takeaway: never treat a gap race with a trailer as winnable. Yield space, do not “contest” the mass.

This also reinforces Section 6.1’s low speed caps for tankers and trailers (45 / 50 / 60): those numbers exist because stopping and crash energy scale brutally with mass and speed.

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Putting speed + space together (exam scenarios)

Scenario A — Table recall. At 60 km/h, overall stopping distance is about 46 m (16 thinking + 30 braking). Tailgating at two car-lengths is far below that requirement.

Scenario B — Expressway car at 100. Overall distance about 92 m. If visibility or traffic prevents keeping nearly a football-pitch-scale gap, you are going too fast for conditions even if 100 is the legal ceiling.

Scenario C — Rain on the highway. Private-car highway max is 80 under ideal dry conditions, but wet road demands much more than the dry 72 m overall figure associated with 80 km/h — and often a lower speed plus a four-second gap.

Scenario D — Following a luxury bus. The bus may stop more slowly when laden; you also must not sit in its blind zones. Give more than the minimum two seconds.

Scenario E — Someone overtakes and dives in. Lift off the accelerator, rebuild the jingle gap, and resist revenge tailgating — which destroys your only crash buffer.

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Memory hooks for Section 6.3

1. Overall column: 10 → 22 → 46 → 72 → 92 as speed goes 20 → 40 → 60 → 80 → 100.
2. Phrase: “Staying too close or trailing for safety.”
3. Weather upgrade: three-second “Playing it Safe!” / four-second “Safer and Sane.”
4. Wet = much more gap.
5. Heavy vehicles = harder to stop; do not contest mass.

Link backward and forward

• Section 6.1 set the legal speed ceilings that keep overall distances inside human-manageable ranges.
• Section 6.2 explained limiters and cameras that try to keep real speeds inside those ceilings.
• Later defensive driving chapters will fold following distance into full hazard routines (SIPDE and special conditions).

For the FRSC CBT, if you remember nothing else from Chapter 6, remember: legal speed is a ceiling; following distance is your parachute; wet weather and heavy vehicles demand more of both.

Quick self-test without looking at the table

Cover the table and answer:

1. Overall at 40 km/h? → 22 m
2. Overall at 80 km/h? → 72 m
3. Thinking vs braking at 60? → 16 m thinking, 30 m braking
4. Bad weather jingle add-on? → “Safer and Sane” for four seconds
5. Wet-road gap vs dry table? → Much more

Why “one car length per 10 km/h” is not the Code method

Some foreign rules of thumb use car lengths. The Nigerian Highway Code method for this exam is the metre table plus the two-second (or longer) jingle. Prefer Code methods on the CBT even if a friend taught a different mnemonic.

Weight disparity in one line

A laden trailer at modest legal speeds can still deliver catastrophic energy to a light car. Space and patience beat “winning” a merge against 30–40 tonnes.