Bridge or tunnel bike shuttle?
In British Columbia there is the George Massey tunnel. The BC provincial government provides a free bicycle shuttle through it since there are no provisions for a bike lane and the autos travel at freeway speed. It is not an international crossing .
George Massey Tunnel Bicycle Shuttle">George Massey Tunnel Bicycle
I can't see why Ontario and Michigan couldn't get together to pay for something like this during the cycling season. Either over the bridge or through the tunnel.