A few of years ago, the Canadian Veterinary Medical Association put out a position statement on the transport of dogs in vehicles in the back of trucks, opposing the unsecure transport of dogs in open vehicles. This was last revised in 2017.
Sometimes legal documents can be difficult to read, but essentially most of Canada made it illegal to travel with an animal in the back of a truck if it was not secured properly. Depending on the province, it may be like the BC Motor Vehicle Act or PEI's Animal Welfare Act.
The other thing to note is the safe travel of pets within the vehicle cab. There are many harnesses and seatbelts for dogs.
I am currently doing the Fear Free certificate, level 1. They mentioned the Center for Pet Safety. In my readings, it appears as though they are the only organization that tests and approves products for the safe travel of pets. Here's where you can find a list of approved products. There are only two harness brands: SleepyPod and ZuGoPet.
I don't have a dog, but I do know that many owners are not securing their pets with seat belts. You can see many dogs travel on the laps of the driver. If that isn't distracted driving, what is??
You can also see a short little article on approved products on the Consumers Report.
If you have a dog or cat traveling with you in a crate, the best spot to put the crate is on the floor of the passenger seat. Or you can get a Sleepy Pod carrier that has safety approval to secure the carrier with the seat belt in the back seat.
Or if you also travel by air with your cat or dog, there is this airline approved bag by ZuGoPet. Check out their website to see a video of how it is put together.
The large dogs that travel in the back of a pick-up truck can be hauled in one of the Gunner Kennels, just ensure that you are using secure ties to keep the crate from moving around in the back of the truck.