This is the 23 Bus in Edinburgh which features in many of Alexander McCall Smiths books. In Espresso Tales Irene Pollock, Bertie Pollock’s very pretentious and over bearing mother (she makes the five year old boy go to yoga, Italian and Saxophone lessons)  insists that Bertie take the 23 to school even though the 27 is more direct simply because you get a better class of person on the 23 as its route includes nice places like Morningside.