Require all public places to have toilets accessible with a medical card

I have a medical condition myself which affects my bowel and makes it very hard to know when you need to go to the toilet, it is very embarrassing 1 minute of fine the next you need to go. I am fed up with getting refused access to toilets at garages etc because people may not know what a medical card is. If it's law that they have to let people with a medical card go to the toilet then I think it would create a better community and also a better understanding that people have underlying disabilities.