If I’m understanding this correctly, there isn’t a US vaccine mandate for US truckers crossing the border to the US. It appears it specifies foreign truckers entering only (ie Canada).
Foreign Truckers Must Be Vaccinated to Enter US Starting Jan. 22
“Starting Jan. 22, travelers entering the United States at land ports of entry — notably along the Canadian and Mexican borders — and ferry points who are not U.S. citizens must be fully vaccinated against COVID-19, the Department of Homeland Security announced.
The requirement, which takes effect at 12 a.m. ET that day, does not apply to U.S. drivers. However, Canada and Mexico have similar regulations in place that do impact U.S. drivers — including truck drivers — who make cross-border runs…”