Allow dogs and cats to travel on public transit

Some countries allow people to take dogs or cats on board a public bus or tram.  And it would be neat if this country could also allow people do to the same.  That way, dog and cat owners wouldn't have to worry about spending money on gasoline just to drive to the vet.  If a dog is well trained not to bother people, the transit systems should allow customers to take dogs with them.  Cats may have to travel in cages or pet caddies.