Sir, - One observes daily the tension on the faces of motorists as they make their frustrated, angry and stressful way through the streets of Dublin. This daily trauma for so many must surely lead to many of the illnesses, physical and mental, which present in our surgeries.While one commends Operation Freeflow, it is merely an attempt to modify a situation which demands more radical measures. The solutions are not easy to find, but surely the savings in terms of human suffering and the prevention of illness would make a major effort immediately worthwhile. - Yours etc.,(Dr) Patricia O'Connell,The Gables,Dundrum.