Just randomly decided to take a look at ON-15 for the first time in 14 years, and discovered it's clearly signed south of ON-401 for a short distance.
This includes full
END/
BEGIN shields which were installed sometime in 2016.
Thus, I'll be extending the route south to a new point called 'RR15' at the location of those shields. This will extend the route 0.37km (0.23 miles) to the south of ON-401.
News entry will be submitted as well when this extension is submitted.