Divided into appropriate speed and undue hesitation. Undue hesitation is the most common one, bear in mind though that this is normally a rider fault, whereas if you pull out when cars are coming that would be a serious fault. Therefore, if you need to err in one direction or the other then being slightly cautious is the better route. Progress faults tend to tot up quickly, as people who struggle to make progress do so everywhere. Look earlier on the approach to junctions to see if it is clear and safe for you to go.