Imagine the cost of changing the entire road network over to use metric.
Here's a zero-cost plan to migrate the road network over to metric: have a transition period where signs may be shown in either unit, then require all replacement signs to be shown as metric. Since all signs must eventually be replaced, over a long enough period of time the whole network will become metric without any marginal cost increase.
The only downside is that for a time, people have to understand both units and how they relate to each other.
76 million, which is not 100s.
Also unironically yes - the time for being polite has passed. Braindead people should be labelled as such in public forums.