Where a vehicle is designed to operate defines much of its form and function. This section covers the five basic environments that must be considered: Air, Ground, Space, Submarine and Water.

This category covers airplanes, propellor-driven drones, countergravity air-sleds, blimps and zeppelins, and anything else that goes through the sky. Though there were attempts to create flying vehicles early on, they almost never worked, and one can consider TR -1 as being the lowest possible technology rating that allows for aircraft.

Vehicles that primarily operate on the ground are among the most common, especially as personal vehicles. This category covers wheeled, tracked, hover and sledded vehicles, and goes back far enough to pre-date the wheel.

Spacecraft will primarily be a feature of science fiction universes, and though they are available at TR 0, they won't be very interesting earlier than TR +1.

Any ship can go underneath the surface of the water. Coming back up is usually the trick. Though submarines date back to the American War of Independance, the earliest practical examples exist at TR -1.

For centuries, advancements in vehicle technology happened in this category. Ranging from the rafts and dug-out canoes of the Stone Age to the modern-day aircraft carrier, these vessels range enormously in size, technology and performance.

Many vehicles will be able to operate in multiple environments. Examples include:

• Aircraft capable of taxiing on the ground;
• Wheeled vehicles capable of amphibious travel;
• Spacecraft that can also maneuver in-atmosphere;
• Submarines with good hydrodynamic hulls, similar to those of World War II;
• Seaplanes, able to land on water, and sometimes designed quite well for it.

For such vehicles, one environment will be its primary environment, and the vehicle must be designed with that in mind. This is a matter of priority, more than anything else! If you wish to design a vehicle capable of performing in multiple environments, your primary environment will be the highest from the list below:

1. Space;
2. Submarine;
3. Air;
4. Water;
5. Ground.