|Peak||every 25-30 minutes||none||none|
|Evening||every 35-40 minutes||none||none|
Though it links two terminals, this route is only of local importance, and takes up to twice as long as the 42 - Derry.
Route 15 was created when route 42 Derry was taken off of local streets in the area. Until 2015, it extended west to the Hurontario and 407 Park and Ride via Derry, and until 2011, a single trip went as far west as Shoppers World; this was cancelled at the same time as route 19 - Hurontario was pulled out of Shoppers World. The current route mirrors a former midday variant running between Cardiff Boulevard and Westwood, which was cancelled because of low ridership.