This short PDF supplement packs a lot in, providing the wherewithall to create 'biotech' vehicles using the standard vehicle design system presented in earlier supplements (originally Supplement 5: Civilian Vehicles and Supplement 6: Military Vehicles, later revised and published as Supplement 5-6: The Vehicle Handbook). As this system concentrated on the end result of your design, rather than the means of accomplishing it, creating compatible living vehicles is not too difficult.
Science-fiction is full of biotech constructs, living creatures which fulfil roles normally occupied by inanimate objects. If you play the 2300AD setting, the Pentapod race uses living starships and vehicles already, or you may want to recreate something you have read about or seen on screen. Used in conjunction with The Vehicle Handbook, you can now do so.
As the vehicle design system is effects-based, most of the work is done using it, and this book highlights the differences due to your design being a biotech one rather than a standard 'rustbucket'. To start with, they are pricey - double the cost of conventional vehicles. You can make most every type of vehicle but its to be noted that they need a 'structure type' as well as the chassis type in the standard design system. Here, you need to decide if the creature is a vertebrate or an invertebrate (i.e. does it have an internal skeleton?). Invertebrate-based vehicles are a little cheaper but they are a bit more vulnerable to damage - a bit odd, ask a cockroach, one of the most durable creatures around and an invertebrate!
Other differences include metabolic type (endothermic or exothermic) and environmental limitations, as well as range and fuel... your biotech vehicle needs to be fed whether or not it's going anywhere! Depending on what they eat, their performance varies - and if your vehicle is a carnivore you will probably have to hunt for it, whilst a photosynthetic vehicle has unlimited range in daylight although it is comparatively slow-moving and may grind to a halt if driven too far at night!
Most biotech vehicles are fairly stupid but some have limited, animal intelligence and can follow simple directions rather than be guided by someone. The supplement also covers defensive capabilities, sensors and even the ability to self-repair when damaged. As for weapons, you can mount normal ones whilst some biotech vehicles have quite novel ones of their own.
Finally, there's a sample biotech vehicle, an airship, to play with. If the idea appeals, however, you'll soon be rooting through novels and films for inspiration - I'm thinking of John Varley's Titan right now, which presented one of Saturn's moons as a construct filled with strange creatures, often filling the roles we'd use machines to fill... It is an interesting concept, and one which will allow you to create some truly alien vehicles, the sort of thing that reminds players that their characters are in an alternate reality.