90 years of the Autocar road test: how performance has evolved

In the decades that followed, engine innovations continued to rain down. Variable valve timing, electronic engine management hybrid powertrains have helped to improve and, more recently, power outputs while also reducing the amount of  fuel being burned.

Of course, massive progress has also been made in transmission and tyre technology since 1928, all of it helping to make the world’s most exotic cars faster than ever and everyday cars much quicker than any Austin Seven driver could possibly have imagined.

The 1955 Mercedes-Benz 300SL may have missed out to the Goliath GP700 on being the road-going pioneer of fuel injection, but it was a groundbreaker nonetheless, capable of 152mph flat out. That record would subsequently be raised by the likes of the Ferrari 365 GTB/4 Daytona, the McLaren F1 and the Bugatti Veyron as power outputs climbed ever higher, while the forthcoming Aston Martin Valkyrie is sold on the promise of far greater on-track performance than that of any other road-legal car.

The Bentley 61⁄2 Litre was armed with a walloping 6597cc straight-six engine to make it one of the fastest cars you could buy in 1928, yet it could only manage a top speed of 92mph. Progress could not come quickly enough. Today, however, we have surely come too far. Even the slowest Porsche 911 you can buy has 365bhp and can hit 179mph. Sports cars have become too quick for the increasingly congested roads they are driven on, and in this blinkered pursuit of ever-higher speeds and faster acceleration, driver engagement and interactivity seem to have been sidelined.

Cars have come a very long way since 1928, not least in terms of their performance. Today, however, it isn’t yet more progress that we need but just a little regress.

Delving into some pretty straightforward top-speed data allows us to see how the rate of progress in road car performance has changed over the years. Or rather, how little that rate of progress has changed, because the statistics show a very stable rate of development.

Plotting those points on a line chart shows a quite linear rate of progress, the biggest leap forward coming with the arrival of the seminal McLaren F1. To demonstrate just how linear it has been, consider this: in the four decades leading up to the 1970s, the top speed of the fastest car increased by 77mph; in the four decades since, it has increased by 75mph. Extrapolating that out over the next 40 years, is it really possible there will be a road-legal production car capable of 334mph come the 2050s?

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