yes definatly

One of the leading lights in vegetable gardening in the UK, Bob Flowerdew regularly uses old car tyres to grow vegetables but I would suggest Googling 'Brighton Permaculture Trusts'' article on the subject and then make your own mind up.

Perfectly safe and saves a lot of digging. Great for growing potatoes as 'earthing up' just means adding a new tyre and filling with earth.
Maybe someone on GoY has used them (I never saw the point of growing veg for just me)

Some people use up old paint and do them in various colours to brighten up the garden.

thank you jimmytheone...think I will just grow flowers in mine

Brighton Permaculture Trust don't seem to be bothered about the potential for toxins leaching into the soil from the hundreds of tyres used in their earthships.
Reality is that tyres degrade so slowly that the potential toxins from 2 or 3 tyres really is so small as to be negligible in comparison with all the cr@p floating around in the air.
I'd be ready to put money on it that you will use some sort of pesticide and insecticide before the season is over, without worrying what they're doing to your food (or to the bees)

A Butterfly Garden could be planted in these tyres too.
Scented perennial plants for them to feed on in June-August.