You can't be the longest Interstate without having a few quirks. In
Montana right by the ID border, I-90 is not a divided highway for a few
stretches. The speed limit there is still "Reasonable and Prudent"
Not only is the I-90 section of the NYS Thruway marked backwards, with mile numbers going down as you go east, but there are two metric only signs when you drive westbound. I believe they are around Syracuse, which is nowhere near Canada.
If you care, I-990 is the highest number given to an Interstate.
Originally from the Syracuse Area, and having a former Thruway Employee as a study hall teacher in high school, here is the legend as to why exit 35 features metric.
The NYSThruway admin decided to test metric sinage (which I am told included [briefly] an 88 km/h speedlimit sign) on the Thruway.
Now the legend part: When one of the metric pushes was on, the state represenative from that district was deadset against it. The Thruway chose his district (Liverpool, next to the former GE plant) as the test site.