Got gas?

Rico says his mother forwards this one:

A driver was stuck in a traffic jam on a highway outside Washington, DC. Nothing was moving. Suddenly, a man knocked on the window. The driver rolls down the window and asked: "What's going on?"
"Terrorists have kidnapped the entire Congress, and they're demanding a ten million dollar ransom, otherwise, they are going to douse them all in gasoline and set them on fire. We are going from car to car, collecting donations."
"How much is everyone giving, on average?" the driver asked.
The man replied: "About two gallons."