I've wondered who would be restricting the streets too? I've seen a couple traffic jams where people got tired of waiting and pulled the 4x4 lever and drove through the grass to the next exit, why stay on the road if your about to loose your life in a big storm?
My parents have a John Deer Gator, it holds 5 gallons IIRC and has the bed behind which could carry more. I've had it up to 45mph before so the performance is close to motorcycle/atv level. Its kind of wide for some places though.