The car was originally going to be powered by fusion or fission or something nifty and
nuclear (something that would allow us not to have to worry about running out of gas)
and those big tanks in the back were representative of this big bulky power-source that
was bolted on to the back of a ’57 Chevy.
We had thought, at one starry-eyed point, that the car would be something that you could
upgrade with more speed, armor, weapons, etc. and that it could be a more important part
of the game—well, the engine and programmer tasking weren’t up to the idea of having a
moving vehicle (madness, I know
in the game so all of that went out the window. The
power source was replaced by a much more mundane 22 cubic feet of cargo-space (more
than any non-wagon vehicle in its class!).
So basically, the Highwayman's powerplant was downsized in order to meet with
People’s State of California emissions standards. It’s often the case that a prototype car
isn’t exactly the same when it goes into production.