Short answer
Rule 57 of the Highway Code says dogs in a vehicle should be "suitably restrained so they cannot distract you while you are driving or injure you, or themselves, if you stop quickly", and lists "A seat belt harness, pet carrier, dog cage or dog guard" as ways to do it1. The Royal Kennel Club says the ideal is "a crate or fixed car cage"2.
What the Highway Code says
This article answers one question from our guide to dog harness types.
Rule 57 of the Highway Code says: "When in a vehicle make sure dogs or other animals are suitably restrained so they cannot distract you while you are driving or injure you, or themselves, if you stop quickly. A seat belt harness, pet carrier, dog cage or dog guard are ways of restraining animals in cars."1
Rule 57 isn't one of the rules the Highway Code marks as "MUST". It's still the standard to follow, and a dog loose in the car can distract you or be hurt if you brake hard.
What the Royal Kennel Club says
The Royal Kennel Club says: "A dog should travel either behind a dog guard, secured with a car-seat harness or, ideally, in a crate or fixed car cage."2
So a car-seat harness is one accepted option, and a crate or fixed car cage is the Royal Kennel Club's ideal. Our crate guide covers that option: wire or fabric crate, and which for the car?
Your options
| Option | Notes |
|---|---|
| Seat belt harness | Listed in rule 571. The Royal Kennel Club also lists a car-seat harness2. |
| Pet carrier | Listed in rule 571. Suits small dogs. |
| Dog cage | Listed in rule 571. The Royal Kennel Club's ideal is a crate or fixed car cage2. |
| Dog guard | Listed in rule 571, and by the Royal Kennel Club2. |
Car harness or walking harness?
Rule 57 says "seat belt harness"1. A harness made for walks isn't necessarily made to restrain a dog in a car. We suggest checking that the maker says the harness is designed for use in a car, and following its instructions for attaching it to the seat belt or anchor point.
We suggest never attaching a car restraint to your dog's collar. A collar puts the force on the neck: a 2020 study on a model neck found no collar tested kept pressure low enough to mitigate the risk of injury when pulling3.
Fitting a car harness
A car harness needs to fit as well as a walking harness: snug, with the front low on the chest and the straps clear of the armpits. Battersea says a good harness avoids pressure on the neck and allows free shoulder movement4. Follow the maker's fitting guide, and see how should a dog harness fit? and how tight should a dog harness be?
Practical tips
These are our own suggestions, apart from the RSPCA's advice on puppies:
- Keep the tether short enough that your dog can't reach you or fall into the footwell. Follow the maker's instructions.
- Check the fit before every journey: harnesses loosen with use.
- Take the harness off once you're out of the car if it isn't also a walking harness.
- Never leave your dog in a parked car on a warm day.
- For puppies travelling in a crate, the RSPCA says not to use their adult-sized crate: "they'll be better protected in a smaller space"5.
Breed harness guides
Every breed fits a harness a little differently. These guides cover the sizes in each brand, how to measure that breed, and the styles that suit it.
- Golden Retriever harness sizeSizes by brand, measuring and fit
- English Springer Spaniel harness sizeSizes by brand, measuring and fit
- Border Collie harness sizeSizes by brand, measuring and fit
- Cockapoo harness sizeSizes by brand, measuring and fit
Find your dog's harness size All breeds
Questions
Is it a legal requirement to restrain my dog in the car?
Rule 57 of the Highway Code says dogs should be suitably restrained1. It isn't one of the rules the Highway Code marks as "MUST", but it's the standard to follow.
What counts as a suitable restraint?
Rule 57 lists "A seat belt harness, pet carrier, dog cage or dog guard"1.
Is a crate or a harness better in the car?
The Royal Kennel Club says a dog should ideally travel in a crate or fixed car cage, and lists a car-seat harness and dog guard as alternatives2.
Can I clip my dog's seat belt to its collar?
We suggest not. A collar puts the force on the neck. Use a harness designed for the car.
Can my walking harness be used in the car?
Only if the maker says it's designed for car use. Check before you rely on it.