While looking at ON 405 on street view, I found some
signage referencing where ON 405 ends. Looking 800m east of the sign, that appears to be
this point, where the maximum speed drops to 40 kph.
Looking at street view for the other 400 series highways to cross the border, the QEW and ON 401 appear to end where they're marked here (well, mostly; it may be worth truncating the QEW to
RR 124, especially if that type of signage is considered enough to mark the endpoint of I-65). There's no signage for ON 402, but the point that was mentioned in the cannf thread corresponds to a drop in the maximum speed to 50, and speed drops seem to be something all these ends have in common (well, except 401, which drops to 60 while 405 exists through a 60 zone to the drop to 40...), so it seems like the MTO employee was right and the MTO's own internal documentation is wrong on that one.
