So for errands I have one of those super-bulky, tall, narrow, heavy so-called Dutch bikes...you know, enclosed drivetrain, single-speed, pushrod brakes. So I took it big-time grocery shopping tonight, w/a strapped on milkcrate to hold my schwag, and boy! if it didn't really change my behavior in traffic. First of all, I couldn't stay close enough to the curb for my comfort... the rear weight of a moderate load of groceries really played havoc w/the bike's balance. And I fled to the available bike lanes ASAP, which isn't at all my normal style. Also, given the bike's capabilities and my reluctance to do anything but get home in one piece, if I ever got above ten miles an hour, I'd like to know how. I need to think of some better tactics for car-free provisioning, I guess. Do most of y'all use trailers, or what?