Only after spending last week driving around California and Los Angeles did I realise just how significant an announcement made at Chevrolet's LA motor show conference was.

In a country - and state - where most cars on the roads are either incredibly vast in size or incredibly bland to look at, the decision to launch the Chevrolet Spark in the US is either very brave or a masterstroke.

First of all, car makers in the US have to do something about reducing their Co2 emissions. The upcoming CAFE regulations are very strict and force firms like GM's hand into launching ever smaller cars (and more efficient cars like the Chevrolet Volt) if they are to be allowed to continue selling big gas guzzling trucks and full-size petrol saloons so popular with a lot of Americans.

There's no doubt smaller cars are becoming ever popular in the US, with Ford finding success with its latest global Ford Fiesta and Ford Focus models and GM itself with its Cruze Range.

But downsizing is only going so far in North America and there is perhaps a reason Ford isn't selling a version of the Ka in North America- it's just too small.

Smart's US distributor Penske found that out the hard way and  pulled the plug on its contract last year, handing the responsibility to sell Smarts back to Daimler after sales fell off the edge of a cliff.

Fiat is struggling with the 500, too. A year after being introduced to the North American audience at the 2010 LA motor show, it was revealed this week that Chrysler was cutting engine production for the car as sales were stalling.

No matter how car makers in the US decide in the boardrooms to go about meeting strict future legislation, buyers voting with their feet will always have the final say.