LPG is preferred over CNG due to its higher energy density, making it more efficient for long-distance travel. It is also widely available and easier to store and transport. CNG, on the other hand, has a lower energy density and requires more storage space, making it more suitable for short-distance travel or stationary use in industries. The choice between LPG and CNG depends on various factors such as the type of vehicle, availability of fuel, cost, and environmental regulations.