Cats shouldn't be allowed to roam free outside of your house. In some places they are licensed and treated as are dogs and are picked up if found wandering loose. Cats are also notorious predators of birds and small mammals and they carry parasites and disease that they leave in the scat that they bury in neighbor's gardens. Surgeons will not operate if a cat has scratched or bitten you near your surgery site due to the possibility of infection. Barn cats serve a purpose by keeping the rodent population under control and they normally stay close and don't bother neighbors but most people do not appreciate free roaming cats in their yards. As far as stopping after striking a cat with your car, how would you know that it wasn't a feral cat? How would you who the owner was? Show a bit of consideration for your neighbors as well as for the well-being of your cat by keeping cats in your own yard. A final thought, coy-dogs view loose cats as fast food snacks.