Apart from independent front suspension, electrically seamless-welded unitary construction and hydraulic brakes, the car also sported front wheel drive using a constant-velocity joint originally developed by Jean Gregoire for use in his own Tracta sports cars (see Front Runners feature). A six-cylinder Traction Avant was launched in 1938 and in many respects embodied design cues that survive to this day in the form of the Xantia which must be the closest successor in Citroen's current portfolio. Following the demise of the car that would 'seat four people under an umbrella' (2CV), the company appears to have moved towards a more conventional line-up. The Xantia is unequivocally aimed at the fleet market with a hierarchical range that runs from entry-level basic to bells-and-whistles executive.

The car I tested was a top-of-the-range V6 Exclusive automatic which, despite its high specification, manages to hit the streets for a reasonable 21,810. But like the Traction Avant in its time, the V6 Xantia, offers an unusually satisfying ride quality, thanks to the intelligent Hydractive suspension system which complements the self-levelling hydraulic suspension that is standard on all Xantias.

In place of the usual metal coil springs, the Hydractive system uses two fluids (nitrogen gas and mineral oil) contained in a sealed sphere. The compressible gas is in a self-contained pocket within the sphere and provides the elasticity that is a necessary component of any suspension system. Load variations alter the volume and pressure of the gas to generate an almost literal 'riding on air' feel to the handling. Independent rear trailing arms link the suspension spheres to each back wheel and the result is a system that reacts to prevailing conditions and selects the most suitable setting.

The clever bit is a third, centrally-mounted sphere which allows the suspension to switch between a 'soft' and 'firm' setting according to a range of parameters constantly monitored by computer. Steering-wheel angle, angular velocity, accelerator pedal movement, pressure in the brake circuit and the amplitude and frequency of body movements are all number-crunched within 50 milliseconds of sudden movement being detected, some three times quicker than any physical movement of the vehicle body. Under normal circumstances around 85 per cent of the ride is on 'soft' setting using all three spheres. What might be termed 'enthusiastic' driving alerts the system which switches to a 'firm' setting that by-passes the central sphere. Drivers who prefer a harder, more 'sporting' ride can select the firm setting manually from a switch on the facia.

And there's more. The Hydractive system controls not only the springing but also the damping which it achieves by modifying the cross section of the liquid circuit that runs between the suspension units to increase or inhibit flow. As with the conventional Citroen hydraulic suspension system there is also a centre-mounted lever to raise or lower the suspension according to road conditions. Up one notch for slow-speed bumpy tracks, up two for wheel changing and right down for servicing purposes.

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