Mazda and the Hydrogen Highway - Our verdict

Hydrogen combustion has also been developed by BMW with the 7 Series. It's certainly another alternative-fuel system to explore, but issues with the cost of hydrogen production, transportation and storage are significant hurdles.

Although there's no doubt that it could work given sufficient investment, it seems that hydrogen is likely to remain further off in the future than other developments, such as new biofuels, greater use of hybrid technology and electric cars.