I never cycle that stretch - it's just too busy. I agree with Jetson's comment about impatient driver behaviour. On my commute into Derby this morning I had 2 examples of drivers who were in a hurry and who could easily have caused a serious accident - one pushing out into the main road from a side street and misjudging my and other road users' speed in the process, and the second a guy who changed lanes next to me without looking so that I had to shout to be noticed.
A lot more needs to be done to make Derby's roads safer for cyclists, especially in the city centre area.