Is Rule 100 a legal requirement?

Yes. Rule 100 uses “MUST” or “MUST NOT”, which marks it as backed by law. Disobeying it is a criminal offence and can lead to a fine, penalty points on your licence, or disqualification.

How is Rule 100 tested on the driving test?

Examiners specifically assess how you respond to vulnerable road users, pedestrians at crossings, cyclists, horse riders and motorcyclists. Late or missing observations here are a common cause of a serious fault, so anticipation is marked closely throughout the drive.

What are the common mistakes related to Rule 100?

The faults examiners most often record around this part of the Code are: passing cyclists or horses too closely or too fast; failing to anticipate a pedestrian stepping out near a crossing or parked cars; not giving way at a crossing when someone is clearly waiting. Rehearsing the safe habit during lessons is the most reliable way to avoid them.

Highway Code · Rule 100

Highway Code Rule 100

Rules for drivers and motorcyclists (89 to 102). A legal requirement (MUST / MUST NOT).

Rules for drivers and motorcyclists
Legal requirement
OGL v3.0

What the rule says

Law · MUST

Rule 100 (Seat belts and child restraints (rules 99 to 102)) The driver MUST ensure that all children under 14 years of age in cars, vans and other goods vehicles wear seat belts or sit in an approved child restraint where required (see table above). If a child is under 1.35 metres (approx 4 feet 5 inches) tall, a baby seat, child seat, booster seat or booster cushion MUST be used suitable for the child’s weight and fitted to the manufacturer’s instructions. Laws RTA 1988 sects 14 & 15, MV(WSB)R, MV(WSBCFS)R & MV(WSB)(A)R 2006 Rule 100: Make sure that a child uses a suitable restraint which is correctly adjusted

Rule text reproduced verbatim from the official Highway Code (Crown copyright) under the Open Government Licence v3.0, see the attribution at the foot of this page.

In plain English

Stripped of the formal wording, Rule 100 comes down to one idea: rule 100 (Seat belts and child restraints (rules 99 to 102)) The driver MUST ensure that all children under 14 years of age in cars, vans and other goods vehicles wear seat belts or sit in an approve… Because it is written with “MUST” or “MUST NOT”, it carries the force of law, ignore it and you are committing an offence, not simply driving badly.

It belongs to the rules for drivers and motorcyclists part of the Code, the habits a confident, considerate driver builds until they are automatic. The aim is not to memorise the sentence word for word, but to understand the hazard it protects you from, so you apply it without having to think when it counts.

If you are learning, treat this rule as one piece of a connected set rather than an isolated fact. The related rules below sit in the same section and reinforce each other, reading them together is how the rules for drivers and motorcyclists part of the Code starts to feel like common sense rather than a list to revise.

Because this is a legal rule, the consequences of ignoring it reach beyond the test: a “MUST” or “MUST NOT” breach can mean a fixed penalty, points on your licence, or in serious cases prosecution. Either way, the safe move is to build the habit early, while a driving instructor can correct it, rather than relearning it under test pressure. That is exactly what the practice routes and coaching in the DriveRoutes app are designed to help with, turning the rules below into the way you naturally drive.

Why rule 100 matters on the road

Pedestrians, cyclists, motorcyclists and horse riders have little protection in a collision, so a moment of inattention from a driver can cause serious harm. Anticipating and giving them room is one of the clearest signs of a safe, considerate driver.

Common faults examiners record

In the rules for drivers and motorcyclists part of the Code, the faults most often written on the marking sheet tend to be the same handful. Knowing them in advance is the quickest way to drive them out of your own habits:

Passing cyclists or horses too closely or too fast.
Failing to anticipate a pedestrian stepping out near a crossing or parked cars.
Not giving way at a crossing when someone is clearly waiting.

On the day

Imagine approaching a cyclist on a narrow stretch during the drive. Applying Rule 100 means easing off early, holding back until you can see it is genuinely safe, then passing wide and slow before returning to your line. The examiner is watching for exactly that anticipation, not a squeeze past at speed.

Quick checklist

Scan ahead for pedestrians, cyclists and riders well before you reach them.
Give them room and time, pass wide and slow.
Be ready to stop at crossings and side roads.

More from Rules for drivers and motorcyclists

Related Highway Code rules

Rule 100, your questions

: Rule 100 (Seat belts and child restraints (rules 99 to 102)) The driver MUST ensure that all children under 14 years of age in cars, vans and other goods vehicles wear seat belts or sit in an approve… It is a legal requirement, it uses “MUST” or “MUST NOT”, so breaking it is a criminal offence that can mean a fine, penalty points, or disqualification.

DriveRoutes is an independent study aid and is not affiliated with, endorsed by, or connected to the Driver and Vehicle Standards Agency (DVSA).