Bit of a pet subject for me, as I did some research on it at university. There are three prevalent design concepts but obviously a myriad of different designs and applications, and to get the terminology right.
Sawtooth or en-echelon design - these typically consist of stands/bays on a 45 degree angle (but some may be more or less acute) that are drive in and reverse out because it looks like the blade of a saw. They typically have a single concourse and a single row of bays - Huddersfield is a classic of the design. Some have perhaps with a set of linear stops on the other side. Bath is a good example of this, and is Kingston.
The advantages is that it can be accommodated on a smaller footprint of land, all facilities and utilities are included in one area, and the general public should be segregated from the bus manoeuvring area. The downside is that each stand has a limited capacity per hour because of the extra manoeuvring and this increases risks of vehicle collision, and it is also difficult for vehicles with centre exits and wheelchair ramps fitted therein. There have been some double sawtooth designs with bays on both sides - Darlington was like that and Leeds still is with the coach station on one side and buses on the other.
End on - another variation of drive in/reverse out with a single concourse area. The stands are at 90 degrees. This means that you need a shorter length of land but more manoeuvring area; in essence, a square patch of land rather than a more rectangular one for a saw tooth. However, being end on means both a larger swing area for vehicles, more blind spots, and therefore more risks of collisions. In a previous life, it was well known that Oxford and the old Gloucester bus stations were bad for vehicles losing mirrors etc. Preston is the biggest and most notable, and was also two sided.
Run Through - if you want a simple design where reversing is taken out of the equation, then simply have long platforms of stops that buses pull into. These also allow a greater capacity per stand. The downside is that for larger bus station, you need more space and potentially several islands of platforms that need to be accessed via pedestrian crossings across roadways - this was the case at the old Wolverhampton bus station but it was rebuilt so that you now have three islands but linked with a single building (a hand with three fingers). As part of my university studies, I wrote to Centro (the old West Mids PTE) to ask why they didn't go for saw tooth designs unlike say WYPTE, and their response was about balancing the risk of reversing with passenger crossings as well as the capacity needed per stand per hour.
As mentioned elsewhere, there are variations such as Middlesbrough's horseshoe of run through stands; Sheffield interchange and Rotherham are also essentially a run through design not a saw tooth even if they do have a small angle built in.
Another thing that
@Dwarfer1979 reminded me about was that in ye olden days with rear loaders, some bus stations were reverse in, drive out - Bedford is the one that sticks in my mind for that.
As for the mention of Hayfield.... There is a whole sub-genre of pathetic bus stations where the grand term is at odds with the facility. Faves of this are seemingly concentrated in the West and Wales with Cinderford and Monmouth being fine examples but Nailsworth is a beauty - a saw tooth with two stands and one shelter located betwixt them.
