This can be divided into two faults; too fast and too slow. People who approach junctions too slowly are generally having issues with using the brakes correctly, i.e. too much emphasis on the rear brake. People who approach junctions too fast are having problems with forward planning. A good approach speed should not impede the flow of traffic while at the same time afford the opportunity to make adequate observation. Remember, don't ride as if you're driving a car! Generally, this is an area for riding faults, but as with other problems if your riding generally lacks forward planning you will very quickly pick up enough riding faults for it to become serious.