Transfer Flow in Chico, Calif, is the only DOT legal GASOLINE transfer tanks we could fine, had that from NTSB, I went with a transfer tank 50 gallons, ( NTSB also told us 90 gals is max legal for us to carry in passenger truck,) it has given us the option of stopping when we want to or can safely and easily do it.
the reason I went with the transfer over the auxiliary is I want to be able to fill my generator too and i want to take the tank in and out when I want to, 4 bolts and a strap i added and its out. no plumbing. You cant put a price on peace of mind and lack of annoyance but this cost $1004, minus online deal I think was minus $40 at the time and 4 day shipping for under $200 from Calif to maine where I was at the time.
crickeydog, don't read this the wrong way, you don't have to run the tank out in order to stop, you can stop anywhere you want to for whatever reason you want to, with a transfer flow aux or transfer tank you simply remove the reason of "need fuel" as one of your reasons to stop and pull over.
Rocky at Transferflow will set you up or shop online and simply fill in your vehicle info and they will pop up a page with tanks in stock that fit your truck!
When Seconds count, the cops are only Minutes away!