'Have you come?'

Helen Remington touched my shoulder with an uncertain hand, as if I were a patient she had worked hard to revive. As I lay against the rear seat of the car she dressed herself with abrupt movements, straightening her skirt around her hips like a department-store window-dresser jerking a garment on to a mannequin.

On our way to the Road Research Laboratory I had suggested that we park among the reservoirs to the west of the Airport. During the previous week Helen had shifted her field of interest away from me, as if allocating myself and the accident to a past life whose reality she no longer recognized. I knew that she was about to enter that period of unthinking promiscuity through which most people pass after a bereavement. The collision of our two cars, and the death of her husband, had become the key to a new sexuality. During the first months after his death she moved through a series of rapidly consumed affairs, as if taking the genitalia of all these men into her hands and her vagina would in some way bring her husband back to life, and that all this semen mixed within her womb would quicken the fading image of the dead man within her mind.

The day after her first sexual act with me, she had taken another lover, the junior pathologist at Ashford Hospital. From him she moved through a succession of men: the husband of a fellow woman doctor, a trainee radiologist, the service manager at her garage. What I noticed about these affairs, which she described in an unembarrassed voice, was the presence in each one of the automobile. All had taken place within a motor-car, either in the multi-storey car-park at the airport, in the lubrication bay of her local garage at night, or in the laybys near the northern circular motorway, as if the presence of the car mediated an element which alone made sense of the sexual act. In some way, I assumed, the car re-created its role in the death of her husband within the new possibilities of her body. Only in the car could she reach her orgasm. Yet one evening, as I lay in my car with her on the roof of the multi-storey car-park at Northolt, I felt her body stiffen in a rictus of hostility and frustration. I placed my hand on the dark triangle of her pubis, the moisture turning it silver in the darkness. She pulled her arms away from me and stared at the cabin of the car, as if about to tear her exposed breasts on this trap of glass and metal knives.

The deserted reservoirs lay around us in the sunlight, an invisible marine world. Helen wound up her window, shutting out the noise of a climbing airliner.

'We won't come here again – you'll have to find somewhere else.'

I had felt the same fall in excitement. Without Vaughan watching us, recording our postures and skin areas with his camera, my orgasm had seemed empty and sterile, a jerking away of waste tissue.

In my mind I visualized the cabin of Helen's gar, its hard chrome and vinyl, brought to life by my semen, transformed into a bower of exotic flowers, with creepers entwined across the roof light, the floor and seats lush with moist grass.

Looking across at Helen, as she accelerated along the open deck of the motorway, I suddenly wondered how I could hurt her. I thought of taking her again along the route of her husband's death – perhaps this would reengage her sexual need for me, rekindle whatever erotic hostility she felt for me and the dead man.

As we were guided through the gates of the Laboratory Helen sat forward over the steering wheel, her slim arms holding it in a strange grip. Her body formed an awkward geometry with the windshield pillars and the angle of the steering column, almost as if she were consciously mimicking the postures of the crippled young woman, Gabrielle.

We walked from the crowded car-park to the test sites. With the research scientist who had greeted us Helen discussed projected Ministry legislation on anti-roll bars. Two lines of damaged cars had been drawn up on the concrete. The bodies of plastic mannequins sat in the crumpled hulls, their faces and chests splintered by the collisions, wound areas marked in coloured panels on their skulls and abdomens. Helen stared at them through the empty windshields, almost as if they were patients whom she hoped to treat. As we strolled through the gathering visitors in their smart suits and flowered hats Helen reached through the starred windows and caressed the plastic arms and heads.

This dreamlike logic hung over the entire afternoon. In the bright afternoon light the several hundred visitors took on the appearance of mannequins, no more real than the plastic figures which would play the roles of driver and passengers in a front-end collision between a saloon car and a motorcycle.

This sense of disembodiment, of the unreality of my own muscles and bones, increased when Vaughan appeared. In front of me, the engineers were shackling the motorcycle to the cradle which would be propelled along its steel rails towards the saloon car seventy yards away. Metering coils led from both vehicles to the recording devices set up on a line of trestle tables. Two cine-cameras were in position, the first mounted alongside the track, lens aimed at the point of impact, the second pointing downwards from an overhead gantry. A video-tape device was already playing back on to a small screen a picture of the engineers adjusting the sensors in the car's engine compartment. A family of four mannequins sat in the car – a husband, wife and two children -coils attached to their heads, chests and legs. Already the anticipated injuries they would suffer had been marked on their bodies; complex geometric shapes in carmine and violet zoned across their faces and thoraxes. An engineer settled the driver for the last time behind his steering wheel, arranging his hands in the correct ten-to-two position. Over the loudspeaker system the commentator, a senior principal scientific officer, welcomed the guests to this experimental crash and jocularly introduced the occupants of the car – 'Charlie and Greta, imagine them out for a drive with the kids, Scan and Brigitte…'

At the far end of the track, a smaller group of technicians prepared the motorcycle, securing the boom camera attached to the cradle which would travel down the rails. The visitors – Ministry officials, road safety engineers, traffic specialists and their wives – had gathered around the point of impact, like a crowd at a race track.

As Vaughan arrived, striding on his long, uneven legs from the car-park, everyone looked round, watching this black-jacketed figure advance towards the motorcycle. I myself half expected him to mount the machine and drive it down the rails at us. The scars on his mouth and forehead caught the air like sabre wounds. He hesitated, watching the technicians lift the plastic motorcyclist -'Elvis' – on to his machine, and then strode on towards us, beckoning to Helen Remington and myself. He scanned the visitors with a somehow offensive gaze. Once again he struck me as being a strange mixture of personal hauntedness, complete confinement in his own panicky universe, and yet at the same time open to all kinds of experiences from the outer world.

Vaughan pushed his way through the visitors. In his right hand he carried a bundle of publicity folders and R.R.L. handouts. He bent over Helen Remington's shoulder as she looked up at him from her chair in the front row.

'Have you seen Seagrave?'

'Was he supposed to come?'

'Vera telephoned me about him this morning.' He turned his attention to me, tapping the bundle of handouts in his grip. 'Get all the paper you can, Ballard. Some of the stuff they give away – "Mechanisms of Occupant Ejection", "Tolerances of the Human Face in Crash Impacts"… ' As the last of the engineers stood back from the test car Vaughan nodded appreciatively, and commented sotto voce, 'The technology of accident simulation at the R.R.L. is remarkably advanced. Using this set-up they could duplicate the Mansfield and Camus crashes – even Kennedy's – indefinitely.'

'They're trying to reduce the number of accidents here, not increase it.'

'I suppose that's a point of view.'

The commentator had called the crowd to order. The test crash was about to take place. Vaughan had forgotten me, starting forward like a patient suburban voyeur half asleep over his binoculars. His right hand, shielded by the publicity folders, was manipulating his penis through the fabric of his trousers. He squeezed the distal end, almost forcing the glans through the threadbare cloth, index finger rolling back the foreskin. All the while his eyes moved up and down the collision course, taking in every detail.

The electric winches which propelled the catapult began to drum at the rails, the cables tautening. Vaughan's hand worked away at his groin. The engineer in charge stepped back from the motorcycle and signalled to his assistant by the catapult. Vaughan switched his attention to the car in front of us, its four plastic occupants sitting up stiffly as if en route to a chapel meeting. Vaughan glanced at me over his shoulder, his face hard and flushed, as if making sure that I was involved.

With a loud jerk, the motorcycle sped down the track, its cables clanking between the metal rails. The mannequin rider sat well back, the onrushing air lifting his chin. His hands were shackled to the handlebars like a kamikaze pilot's. His long thorax was plastered with metering devices. In front of him, their expressions equally vacant, the family of four mannequins sat in their vehicle. Their faces were marked with cryptic symbols.

A harsh whipping noise came towards us, the sound of the metering coils skating along the grass beside the rail. There was a violent metallic explosion as the motorcycle struck the front of the saloon car. The two vehicles veered sideways towards the line of startled spectators. I regained my balance, involuntarily holding Vaughan's shoulder, as the motorcycle and its driver sailed over the bonnet of the car and struck the windshield, then careened across the roof in a black mass of fragments. The car plunged ten feet back on its hawsers. It came to rest astride the rails. The bonnet, windshield and roof had been crushed by the impact. Inside the cabin, the lopsided family lurched across each other, the decapitated torso of the front-seat woman passenger embedded in the fractured windshield.

The engineers waved to the crowd reassuringly and moved towards the motorcycle, which lay on its side fifty yards behind the car. They began to pick up the sections of the cyclist's body, tucking the legs and head under their arms. Shavings of fibreglass from its face and shoulders speckled the glass around the test car like silver snow, a death confetti.