From today, any child under the age of 12 or 4ft 5in (135cm) in height will have to be in a car seat when travelling in a car in the UK.
Put as simple and unconfusing as possible it means the following:
a) If your child is under 12 and is shorter than 135cm they have to be in a booster seat.
b) If they are under 135cm but over 12 then they don't and can use an adult seat belt.
c) If they are over 135cm but under 12 then they don't and can use an adult seat.
"Small children need the protection that baby seats and child seats are designed to provide. Seat belts are designed for adults. Children who have grown out of child seats still need to use booster seats and booster cushions", said Stephen Ladyman, Road Safety Minister. "We estimate that these changes could prevent over 2000 child deaths or injuries each year."
However, recent survey's suggest that some motorists are still confused about changes to laws affecting child seats.
The introduction of the new law is likely to make the school run havoc, with every child in the car under 12 requiring a booster seat.
The new law will also mean it will become illegal to use a rear-facing child restraint in a vehicle seat which is protected by an active front airbag.
The government has launched a website childcarseats.org.uk to help offer assistance with parents still confused with what they can and can't do.