The fastest race track on earth

The superspeedways, of which there are two on the CART calendar, are fearsome two-mile ovals which, even with regular rule changes to keep top speeds down, see average speeds topping 230mph. Michigan and its counterpart at Fontana in California remain unparalleled for sheer speed and excitement on the CART schedule.

Bearing in mind that the fastest recorded speed of a Formula 1 car does not even approach the average speed at Michigan - even top cars struggle to reach 220mph at Hockenheim - that's an indication of the phenomenal speeds involved. Now add to this thirty cars jostling for position, and another statistic - that due to the 'draft', the lead has been known to change around 90 times in a 250 lap race.

At Michigan, up to four lines can be run around the turns, meaning the cars will not just be running at speeds in excess of 200mph, but actually racing four-abreast around the 70 foot wide banking for the duration of the 500-mile race.

With the new speedway wing packages introduced over the last couple of years, speeds have fallen, but consequent changes have involved closer racing and a greater number of lead changes. The 'Handford' wing, a spec device fitted to all cars, creates drag in abundance without adding downforce, and therefore slows the cars while adding to the potential for drafting.

Speeds have not been harmed too much, however: at testing in May, laps of 230-231mph were regularly achieved. The lap record was set in 1996, by Jimmy Vasser in a Ganassi Racing Reynard-Honda, who recorded 234.665mph during qualifying for the Marlboro 500 that year.

To put that in context, a Boeing 747 'Jumbo Jet' would have left the ground at a speed 54mph short of what Vasser averaged over a lap of Michigan!

The formula for this phenomenal pace is in the length of the track and its high-banked turns. The 'D' shaped oval is sloped at 18 degrees in the turns, five degrees on the long back straight, and 12 degrees on the front straight, which actually has a pronounced curve.

In addition, the back straight is a relatively massive 2,242 feet long, at the end of which the cars will build up to over 240mph. This compares to a straight length of 1,760 feet at the Homestead oval and 1,200 feet at Nazareth. Homestead and Nazareth both have a maximum banking in the turns of six degrees, a third of that of Michigan. The slope on the banking enables the Champ Cars to maintain a far higher cornering speed than the shallow banking at most 1.5- or one-mile ovals.

The entire field circulating around the Michigan 'bowl' tends to create a localised tail-wind around the circuit, meaning that race speeds can approach those of qualifying, and even with pit stops and yellow flag periods, race speed averages have been as high as 189mph. This means that in two-and-a-half-hours, the cars will have covered the distance between Northampton and Aberdeen with cautions and stops added, and while negotiating turns and traffic throughout the whole distance.