Have the tolls been suspended yet?
or is that automatic when ever the state goes on hurricane alert?
Good question--and I don't know. However, I did find a very interesting site with vehicle traffic count--many locations in So FL have hourly figures. The Key Largo table indicates merely average traffic southbound and northbound into/out of the Keys since yesterday, with a slight increase in northbound traffic the past couple of hours.
I bet they double or triple, law of supply and demand. The demand for road use goes up but the supply of roads does not change.