Behind closed doors at a proving ground, a new car may find itself ageing ten years in 20 weeks. Paul Markillie goes along for the ride ...

From INTELLIGENT LIFE Magazine, Summer 2011

We complain about the state of the roads, and this one is making my teeth rattle. The car is only going about 30mph but the wheels are frantically drumming up and down over uneven cobblestones. It is a tough one for vehicle integrity, says Miguel Fragoso, using engineer-speak to describe a road capable of shaking a car to bits. Yet this piece of road will never be resurfaced, because Fragoso likes it just the way it is. 

He is managing director of the Millbrook Proving Ground, a sprawling 700-acre site hidden away in Bedfordshire behind security fences and high embankments. This is to prevent the car-world paparazzi snatching pictures of the new models manufacturers bring to test here. Even the lens on my mobile phone has been covered with a tamper-proof security seal. Not that the cars here look pretty. Many have not been washed for weeks and are covered in layers of dirt and dust. That too is deliberate.

Millbrook is a sort of automotive time machine. A shiny new model arrives, and after about 20 weeks it will have been exposed to the equivalent of ten years of severe weather and wear-and-tear comparable to being driven 160,000 miles or so—the lifetime of a typical car. Day and night it will have been driven fast and slowly, up and down hills, around twisty corners, through salt-water baths to accelerate rusting and along gravel roads to pit the paintwork. It will also be frozen, baked, soaked in water to reveal leaks, and bounced along the notorious Belgian Pavé, the one-mile circuit we are on. This is built from blocks of paving with rough sections and random depressions. The pounding it gives the suspension is so severe that after about five laps a car needs to be driven into a trough of water to cool its dampers down. 

Carmakers also test future models on public roads, often disguised with stick-on panels, and take them to harsh environments, including roads within the Arctic Circle and deserts such as the Mojave in California. But proving grounds like Millbrook allow a lot of tests to be done in one place and in repeatable, carefully measured conditions—including the ultimate wrecking exercise: strapping in dummies and smashing the car into a steel wall to establish its crashworthiness. 

During the accelerated ageing, engineers take the cars apart and examine them for worn and broken parts. This allows carmakers to tweak designs and change production methods to prevent failures which would be costly for them to fix under warranty, and embarrassing if vehicles have to be recalled. Such testing processes have helped carmakers to raise their quality, resulting in warranties getting longer. Some engine guarantees have gone from three to five years and more; anti-corrosion warranties now sometimes extend beyond ten years.

The engineers are not just looking for wear and tear. Among the most irritating problems for motorists are noise, vibration and harshness, known as NVH in the business. Shaking things up on the Belgian Pavé is one way of testing NVH, but there are others. Cars undergo extreme temperature variations, for instance. Jump in a car on a freezing morning and the temperature could be -10°C. Five minutes later, with the heater blasting away, the temperature of the dashboard could have soared to 30°C. As different materials expand at different rates when heated, this can cause niggling rattles to occur. Carmakers do not want their precious models to gain a reputation for rattling every time the heater is turned on.