Special Supplement 3: Vehicle Upgrade Manual adds many new design options to Supplement 5-6: Vehicle Handbook.
Three brand new chassis types are on offer; ekranoplans, rocket planes and ornithopters. Also in this book are rules for vehicle maintenance, design flaws, new modifications, and new weapons. A system for creating ultra-heavy vehicles is also present, suitable for making the very largest planet-bound vehicles. Finally, there is a section for making vehicular robots and drones.
Several new vehicles are provided, making use of the new design options and rules.
This book requires Supplement 5-6: Vehicle Handbook.