So, going to start off, Oscar & julmac, sorry to have to tell you both, you're technically losing your ON-17 clinch and a segment of the TCH.
As far as I can tell, only 1 other user is affected by this reroute, and that would be dfilpus.
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This reroute happened sometime after Oct '18, as StreetView still shows ON-17 on the old road then. I can confirm the new road is opened due to some imagery showing half/half of the road on the new route already. The reroute is just west of SH-622 between the KM's of 259 & 262.
There will be 'closed' points of '*OldON17_IgnW' & '*OldON17_IgnE' at each end of the reroute.
I only noticed this when I saw a few areas of ON-17 that were out of tolerance (going to have to double check the entire route later and fix areas where this happens).
This has been submitted here:
https://github.com/TravelMapping/HighwayData/pull/4656