Everyday habits that can undo a good seat, and what to do instead. Each one comes from a road-safety body, a health service, a tester or crash research.
Nothing extra in the seat
No puffy coats under the harness. Take the coat off, buckle up, then put the coat on backwards over the top.
Nothing that didn't come with the seat: no head straps or bands, inserts, padding, or harness and buckle covers.
Why: seats are crash tested exactly as they're sold. Extras haven't been tested with your seat and can change how it protects your child. A puffy coat squashes flat in a crash and leaves the harness loose.
Consumer Reports · Source · Which? · Source · American Academy of Pediatrics · Source
One belt, one person
Never hold a child on your lap, and never put your seat belt around yourself and a child.
A sling or front carrier doesn't make it safe. The baby is still between you and the belt.
Why you can't hold on: in a 50 km/h crash, a 7.9 kg baby is slowed at more than 30 G. Researchers measured how hard belted adults can hold a baby dummy on their lap, and it was far less than that. The baby would almost certainly hit the dashboard or windscreen.
Why the belt makes it worse: your own body is thrown forward too, and the baby is crushed between you and the car's interior.
Mohan D, Schneider LW. An evaluation of adult clasping strength for restraining lap-held infants. Human Factors, 1979 · Source · Torbay Council road safety · Source · HSE Ireland (illegal and dangerous) · Source
Seat belt when you're pregnant
Always wear it. Diagonal strap between your breasts. Lap strap low, over your upper thighs and under the bump.
Never across the bump.
Why it matters: in a study of real crashes involving 57 pregnant women, wearing the belt properly gave 4.5 times the odds of a good outcome for the baby. The researchers estimate about half of babies lost in crashes could be saved if every pregnant woman wore her belt properly.
Why not across the bump: low on your hips, the belt presses on bone. Across the bump, it presses on the womb and can tear the placenta away. In a computer simulation of a 40 km/h crash, the placenta separated about five times more with the lap belt at the belly button (36%) than low across the hips (7%).
nidirect (Northern Ireland government) · Source · Department for Transport, THINK! · Source · Klinich KD et al. Fetal outcome in motor-vehicle crashes. American Journal of Obstetrics and Gynecology, 2008 · Source · Severity of placental abruption in restrained pregnant drivers (computer simulation). International Journal of Environmental Research and Public Health, 2022 · Source
Second-hand seats
Newer tests are tougher. Testers keep raising the bar: ADAC and ÖAMTC made their crash tests stricter in 2025. A seat that did well in recent tests has met a tougher standard than an older one.
You can't know its history. It may have been in a crash, and the damage may not show. The instructions are often missing.
If you must use one, only take it from family or friends you trust, never from a second-hand shop, an advert or an online seller.
ÖAMTC child seat test, spring 2025 ("test criteria have become stricter") · Source · RoSPA, Child Car Seats · Source
After a crash
Replace the seat if it was in the car during a collision, even if you can't see any damage. It may protect less next time.
Check the car's seat belts and fittings too, and include the new seat in your insurance claim.
If in doubt, replace it. Some makers give their own rules, so check your seat's manual.
Wherever possible, don't carry children on a moped, scooter or motorbike. If a child does ride, they sit behind the rider, never in front.
Never a baby in a front carrier, or a child in front of the rider. In crash tests of a motorbike hitting a car, a child dummy sitting in front hit the handlebar, then the car, and was crushed between the car and the rider's body, with a high risk of severe chest and neck injury.
Helmets save lives. Across studies of motorcyclists who crashed, wearing a helmet cut the risk of death by 42% and of head injury by 69%.
Global Road Safety Partnership, Safety of passengers on powered two-wheelers, 2024 (recommendations) · Source · Koetniyom S, Carmai J et al. Kinematics and injury analysis of front and rear child pillion passenger in motorcycle crash. International Journal of Automotive and Mechanical Engineering, 2018 · Source · Liu BC et al. Helmets for preventing injury in motorcycle riders. Cochrane Database of Systematic Reviews, 2008 · Source
This is general guidance, not a substitute for your seat's manual, your car's handbook or local law.