Frequently asked questions

• Drivers have a legal responsibility to ensure that all passengers under 17 are appropriately restrained in the vehicle.
• All children under 150cm in height or 36kg in weight must use a child restraint system (CRS) suitable for their height and weight while travelling in a car or goods vehicle (except taxis). 
• It is illegal to place a rear-facing child car seat in the front passenger seat where there is an active airbag.
• Children must travel in a rear-facing car seat until they are at least 15 months old.  Safety experts recommend keeping children rear-facing for as long as possible.

A child can legally stop using a child car seat once they reach 150cm in height or 36kg in weight. 

Safety recommendation: Children should continue using a car seat until they reach 150cm, regardless of weight.

There is no law against children sitting in the front seat as long as they are using a child restraint suitable for their height and weight. However:

• It is illegal and highly dangerous to place a rear-facing child car seat in the front passenger seat where there is an active airbag. 
• The back seat is the safest place away from airbags and the dashboard.
• If a child must travel in the front passenger seat, ensure they are using a forward-facing car seat that is suitable for their height and weight.  Where possible, the biggest and strongest child should occupy the front seat.  Position the front passenger seat as far back from the dashboard as possible, as this could help reduce the severity of injuries should the airbag deploy in a collision.

 

Children must remain rear-facing until they are at least 15 months old. We recommend keeping children rear-facing for as long as possible (often up to age 4 or beyond ). 

Only switch when the child outgrows the rear-facing limits (height or weight), not just because they reach a certain age.

The transition from a child car seat to a booster seat should be based on your child’s height rather than their age.

• High-back booster seat:  recommended for children between 100cm and 150cm
• Backless booster seat:  recommended for children between 125cm and 150cm

 Booster seats help position the vehicle seat belt correctly across a child’s body, reducing the risk of serious abdominal and neck injuries in a collision.  The seat belt should rest across the shoulder (not the neck) and across the pelvis (not the stomach).

 High-back booster seats provide additional head and side-impact protection and should be used for as long as possible, up to a height of 150cm.  Backless booster seats do not provide head or back support and are intended for older, taller children who are nearing the end of their time using child restraints.  

Once you have followed the instructions on how to fit the child car seat, check the fit by:

1. Movement test: Hold the seat at the base and try to move it side-to-side and forward.  It should not move more than about 2-3cm (1 inch).  If it wobbles more than that, it’s too loose.
2. Installation check:

• For ISOFIX, make sure both connectors are fully clicked in (listen for an audible click and look for the green indicator).
• For seatbelt installation, ensure the belt is routed exactly as shown in the manual and pulled tight with no extra slack. 

1. Visit our ‘Check it Fits’ service to get your car seat checked by one of our experts.  This service is a full-time, nationwide, free service and our experts will check the car seat is fitted correctly, and will answer any questions you might have.  Check the upcoming ‘Check it Fits’ locations here.

Buying new is always the safest option.  Second-hand car seats can be safe, only if the following applies:

• You know and are completely sure of its history
• Must never have been involved in a crash (even if no damage is visible)
• It is within its expiry date (generally 5-10 years; check the exact expiry date which can be found on the sticker on the seat or embossed in the plastic shell)
• Must include all its original parts and instructions
• It comes from a trusted source (e.g. family or close friend)
• It complies with EU safety standards – check for the orange ‘E’mark label.  The label should indicate compliance with either ECE R44/04 (older standard) or R129 (i-Size), which is the new standard.

 

• Yes, a car seat should be replaced after a collision, even if there is no visible damage. Impact forces can cause hidden structural weaknesses that may reduce the seat’s ability to protect a child in another collision.  As a general guideline, if the vehicle sustained more than bumper damage, you should seek advice and consider replacing the car seat.  We recommend contacting the car seat manufacturer directly for guidance specific to the make and model of your child car seat. 
• If the car seat is being replaced following a collision, it should be made unusable before disposal.  For example, cut the harness straps and/or damage the polystyrene components to help ensure the seat cannot be use again. 

 

ISOFIX

• A built-in system that lets you attach a child car seat directly to your car’s chassis
• Uses metal anchor points instead of a seat belt
• Reduces the risk of incorrect installation
• Often includes visual indicators to confirm it’s fitted properly

 i-Size

• A European safety standard for car seats (Also known as R129)
• Requires rear-facing car seats for longer (at least until 15 months)
• Classifies seats by child’s height rather than weight
• Includes improved side-impact protection testing
• Designed to work with ISOFIX systems for better compatibility
• Since September, 2024, only child car seats approved under R129 (iSize) standard  can be sold within the EU.  However, child car seats certified under the older R44 standard that are already in use remain legal and can continue to be used.

 ISOFIX is how the seat attaches to the car, while I-Size is the safety standard the seat is built to meet.

Choose a car seat that is suitable for your child’s height and weight, and always follow the manufacturer’s guidelines. (Link to child car seats guide)

Rear-facing seats provide better protection for a child’s head, neck and spine.

A correctly installed car seat significantly improves protection for your child in a collision. Always follow both the car seat manufacturer’s instructions and your vehicle owner’s manual to ensure the seat is fitted correctly.  For added peace of mind, you can visit our ‘Check it Fits’ service, where one of our experts will inspect your car seat installation, confirm it is fitted correctly, and answer any questions you may have.   ‘Check it Fits’ is a free, full-time nationwide service.  You can find details of upcoming ‘Check it Fits’ locations here.

The back seat is the safest place for children in a car. 

Make sure the harness is snug, flat and not twisted.   Avoid bulky clothing (especially thick winter coats and puffy jackets) as they can compress during a collision, leaving extra slack in the harness.  A harness that seems tight before a collision may become loose when the padding compresses increasing the risk of injury or ejection.  

Many aftermarket products (items not supplied with or specifically approved by the car seat manufacturer) have not been tested with your particular car seat and may affect its performance in a collision.  Examples of accessories that may be unapproved include:

• Head supports
• Strap covers or harness pads
• Toys that attach to the harness

You should only use accessories that come with the car seat or are explicitly approved by the car seat manufacturer for that specific model.

Anything that changes how the child harness, or seat functions can potentially affect collision protection.

 

Ideally, fit your child’s car seat in the back seat. This means that they are away from airbags and the dashboard. If you must place the child car seat in the front, make sure that it is suitable for the child’s weight and height. 

Do not use a rearward-facing child car seat in the front seat where there is an active airbag.  Choose the biggest and strongest child to go in the front. 

Once you have followed the instructions on how to fit the child car seat, it is easy to test if it is fitted correctly. The child car seat should sit firmly on the back seat with no forward or sideways movement when tested. You can simply push the seat to test this, or you can fasten the harness straps and pull it from the centre as if to exert a similar force a child would in the event of heavy braking. 

If you are in any doubt, you should visit our child car seat checking service, our Check it Fits Service, our child car seats page and our YouTube channel. 

ISOFIX is the international standard of built-in attachment points in a car’s structure to fit a child car seat. A child car seat can easily be plugged into the ISOFIX system,  greatly reducing the risk of fitting the seat incorrectly. 

 

Many new vehicles have ISOFIX points built in when they are manufactured, and child seat manufacturers are more commonly producing child car seats that suit the ISOFIX system. 

i-Size is a European standard – Regulation 129. The key benefits of i-Size-standard seats are that they can be fitted to most ISOFIX systems and they provide increased support for the child’s head and neck. They also provide better side-impact protection in the event of collisions. 

An i-Size seat also allows your child to stay rear-facing for much longer (up to 15 months in a rearward-facing baby seat). The categorisation of these seats is based on height and size rather than height and weight. 

 

Children should stay in rear-facing car seats for as long as possible. There are seats available now that can accommodate children up to 25kg (approx five to seven years’ old) and these are highly recommended as they are up to five times safer than forward facing car seats.  

Only move a child from a rearward facing child seat once they have gone over the maximum weight for the seat, their eye level is in line with the top of the seat, or the top of their head ‘crowns’ (is higher than) the top of the seat. You will need to check the manual to see which one of these measurements applies to the particular car seat.  

Older children should use a high-back booster seat for as long as possible – up to 36kgs (up to 79lbs) – rather than the booster cushion by itself. The booster cushion on its own provides no back or head protection. Booster cushions are available for children from 15kgs (33lbs). However we do not recommend using booster cushions for children under 22kgs (48lbs) because they do not provide as much protection to the child as a high back booster seat that has head, neck and back protection. The adult seat belt goes around the child and through the appropriate guides of the seat, so it is important that the safety belt is correctly adjusted and that there is no slack in the seat belt when fastened.  

Boosters are intended to raise the child up so that the seat belt is positioned correctly on their bodies (on the shoulder, not the neck; and on the pelvis, not the stomach).  

Car seats that use the adult seat belt to secure the seat should not have the seat belt buckle sitting on the child car seat. Buckle crunch is where the buckle of the seat belt is resting on the frame of the car seat. The movement of the car while travelling could cause the buckle to open. Also, on impact, the buckle could be broken causing the child car seat to become loose or detached in the car, giving little or no protection to the child in the seat. The webbing of the seat belt is much stronger and it should hold the seat in place. The photo below shows how to recognise buckle crunch.

 

1. Before you fit a child car seat 

Read the manufacturer’s instructions carefully. If you have lost your manual, you should get a replacement from the retailer or manufacturer. 

The seat belt must pass through all the required seat belt-routing guides (red or blue) according to the manufacturer’s instructions. Remember, some guides are only intended to be used on one side or the other, depending on what side of the car the seat is being fitted on. 

 

 

2. Helpful tips for fitting child car seats 

• You should kneel into the seat exerting your full weight. Then, tighten the seat belt as much as you can to remove all the slack. This ensures that the seat is fitted as tightly as possible. 
• Hand pressure is not enough when you are securing the child car seat with the seat belt. 

• It is safer to fit a child car seat in the back. If fitting a child car seat into the front seat, roll the seat itself back as far as it can go away from dashboard. 
• If you take the child car seat out of the car, make sure you fit it properly every time you put it back in. 
• If your child car seat stays in the car permanently, you should still check it regularly to make sure it is securely held and there is no slack in the seat belt. 
• Never adjust or modify the seat or seat belt. A child car seat should be suitable for the child and be compatible with the car. Therefore, modifications (changes) to either should not be necessary. 
• Get a child car seat expert to fit the child car seat or check it for you if you are in any doubt. 
• The safety belt buckle should not rest on the frame of the child seat causing buckle crunch. 

 

To be effective, child restraint systems (seats, cushions and so on) must be fitted and used correctly. Surveys have consistently shown that a high proportion of child restraints are incorrectly fitted, usually for one or more of these reasons which are easy to watch out for: 

• Safety belt has too much slack in it causing the fitting to be very loose. 
• Safety belt not routed through child seat correctly. 
• Buckle resting against the frame of the child car seat, causing buckle crunch which may cause the buckle to open. 
• Handle on baby seat not positioned properly. 
• The child car seat is too big or too small for the child. 
• Child car seat not compatible with the car. 
• Child car seat has exceeded the manufacturer’s recommended guideline for duration of use and is in bad condition. 

It is very hard to offer advice on all types of 'add-on' items as there are so many different products. The general advice is that when thinking about using any product that didn't come with the original car seat itself, it's important to make sure they have been crash- tested and that the manufacturer of the child car seat in question has approved that the product can be used with the car seat . You may need to contact the manufacturer directly to establish this but it's so important to ensure that the product will not cause any change to how the child car seat would perform in a collision or cause any harm to the child.

 

Even if the product is crash tested and/or approved for use with the car seat, it is also important to know how to fit them correctly too.  As far as we're aware, there are only two harness attachments that have been crash-tested for use in car seats: Be Safe Belt Collector and the 5 Point Plus.  

 

Often the reason children might take their arms out of the straps is because the straps are not adjusted correctly and may make the child uncomfortable, prompting them to take their arms out. Another reason may be that the child is wearing a bulky jacket, which allows them more space to get their arms out. We recommend using light fleeces or blankets during winter as this means the straps can have as much contact with the body as possible.  If the child's head is leaning forward while travelling, there may be other adjustments that could be made to help this and you should seek advice from a child car seat expert.

 

Therefore, before you consider using any new attachments, we would recommend you arrange a session with our Check It Fits team and they will be able to help you assess whether the straps are adjusted correctly or any other features that might be leading to your child getting their arms out or their head to lean forward.  

There is no specific road traffic regulation that states a safety belt extension cannot be used in a vehicle.  Therefore, to ensure a vehicle owner is not affecting the performance of their vehicle’s safety belts they must only use devices that are type approved (visually this will be verified by the presence of an ‘E’-mark or ‘e’-mark) for that safety belt installation.  This is an important point, as the device may have an ‘E’ or ‘e’-mark but be approved for another vehicle or safety belt installation entirely. To determine which safety belt extensions are approved for their vehicle (if any), a vehicle owner should consult the vehicle manufacturer for advice in this regard. 

Using seat belt extenders to solve one problem can actually create new ones like buckle crunch or buckles resting on soft parts of the body.