For decades, a sizeable proportion of America’s car makers have resisted the pressure to improve the fuel efficiency of their beloved gas guzzlers – and we've been treated to a succession of fantastically loud, extremely powerful, not-especially-green-but-heroically-mean machines as a result; cars such as the Corvette, the Trans Am and the Dodge Charger; and more recently the Viper, the Mustang GT500 and a whole raft of SUVs, pick-ups and the like.

As of 2025, however, the days of such cars would appear be over.

The average fuel consumption for an American car at the moment is approximately 29mpg, but that will need to rise to a heady 54.5mpg by 2025 now that President Obama has signed his country’s car makers up to a sweeping new industry agreement on fuel efficiency. And Detroit, it seems, is well on board.

Why? Because the car makers of America have realised that the opinions of the car drivers of America have altered fundamentally in the last few years. Green is now cool in the USA while gas guzzling is, like, so totally last century, which means the smart dollar can now justifiably be aimed in the direction of the development of more fuel efficient cars. Which, in the grand scheme of things, is probably no bad thing, even if it does mean the end of the road for the Corvette and its ilk as we know it.

But does this also mean the end of such cars in Europe? And if so, is that a good or a bad thing overall?

Well yes, eventually, it probably does spell the beginning of the end for the horsepower race, both in the US and in Europe as well. But whether you regard this as being a welcome piece of news or not depends mainly on how you regards the likes of the BMW M5 (552bhp/27mpg) and Mercedes SL63 (537bhp/28mpg) and their kin, right now, in 2012.

Personally I’m split straight down the middle. As an unashamed car nut I’m inevitably of the persuasion that too much is never enough; I love the sensation of being fired towards the horizon like a human cannonball, wondering if the few remaining shreds of my hair might fall out in the process.

But at the same it’s equally obvious that we’ve already gone too far in the horsepower dust up, and that the situation has already got way out of hand. When you start making cars that weigh more to make them safer, and then discover that you need to give them more power to make them faster (because they weigh more than they did), you know it’s all going to end in tears eventually.

In light of which, the significance of what happens in 2025 won’t come a moment too soon.