I was thinking the same. I'm all for trikes, but not mixing in with cars, if the driver is impaired enough to not be driving a car.
My dad was driving right up until the week he went into the hospital, at age 89. The week before, he had driven himself down to a restaurant at the beach that sold Boston style lobster rolls... he had to take a special driving test a couple of years ago, in CA, but he passed. I doubt he would have passed the next one. And, I know he could not have managed a trike.