How many gallons of gas does a anhydrous ammonia tanker truck hold?

Ammonia in a gaseous state would be measured in cubic feet. Ammonia tanker trailers would be sized based upon how many gallons of liquid ammonia they could legally carry in the state/states in which they would operate and the weight limit of each of these states. Generally speaking, Anhydrous Ammonia would weight 5.15 pounds per gallon at 60 degrees Fahrenheit. Example, let's say that a state's maximum legal load limit for it's roads is 80,000 lbs. The truck pulling the trailer weighs 14,000 lbs and the trailer that is being pulled weighs 23,000 lbs. The combined truck and trailer weigh 37,000 lbs leaving you 43,000 lbs of product you can carry before you reach the maximum legal load limit of 80,000lbs(80,000-14,000=66,000, 66,000-23,000=43,000). This would allow you to legally haul 8,349 gallons of liquid anhydrous ammonia (43,000/5.15=8349.515).