Concepts in roll-interconnected hydro-pneumatic suspensions with hydraulic and pneumatic couplings are developed and analysed for enhancement of anti-roll properties of heavy vehicles. The mathematical models of the roll-coupled suspensions are formulated considering the fluid properties and variable damping valves. The roll properties of fluidically connected suspensions are compared with those of unconnected suspensions with and without anti-roll bar, and dynamic responses of a heavy vehicle with different suspensions are investigated under excitations arising from road roughness and directional manoeuvres. The results indicate that both interconnected suspensions could considerably improve roll stiffness without affecting vertical ride, while hydraulic interconnections could further enhance the roll mode damping properties