There will be 2 extra services between 8 and 9 in the morning, reducing intervals between services from 15 minutes to 10 minutes approximately.
The announcement also implies there will be extra services on the 15A and 15B routes, but a count of timetabled departure times shows no change in the overall number of buses (a slight reduction in 15B, see below), although there is a slight variation in departure times.
A 15D service is also being introduced between Whitechurch and Ringsend which will pass through Terenure on a similar route to the 15B. However there will only be 1 bus on weekday mornings and 2 services in the evenings, which appear to replace corresponding 15B services.