If I were cycling past a car and the door began to open, I would (and do) respond on the assumption that that door is going to open all the way. You don't have

If I were cycling past a car and the door began to open, I would (and do) respond on the assumption that that door is going to open all the way. You don't have to be moving fast for that to be problematic. Moreover, there are plenty of places you have continuous parked cars. If you slowed to a genuinely safe speed you may as well be walking.