Not an option for me... when I go all out and don't get caught by too many lights, my ride is already 35 min. If I were to slow down sigificantly, the bike commuting equation loses its appeal, as the time commitment vs exercise quotient becomes uncompetitive with simply running (or nordic skiing, if necessary). Not to work and back, by the way , I mean in my free time, or best of all, during lunchtime on workdays.