Buses developed by Formula One team Williams are set to hit London’s streets this year after “very promising” test results.

Williams, nine times winners of the F1 championship, have transferred fuel-saving technology first used in its race-cars to the world-famous London double-decker bus and say the project is now at the “very promising” stage.

“The potential market is huge once we get into volume and driving cost down,” Alex Burns, Williams CEO is quoted as telling Bloomberg.

The secret behind Williams’s fuel-saving lies in a fly-wheel fitted to use the energy realised by a vehicles’ braking system that is otherwise wasted. The fly-wheel technology was first envisaged for F1, but costs were felt to be too high for use in motorsport.

Instead, Williams’s research team switched their attention to public transport and, in 2012, Williams and bus company Go-Ahead signed a deal which eventually saw the construction of six prototype double-deckers. Double-deckers, with their greater weight and therefore greater braking energy, are seen as ideal for the fly-wheel technology. One of the prototypes will now be sent onto London’s roads for final testing and, if successful, then it’s a selling job with Transport for London.

Last year there were dashed hopes that London was to get a Formula One street race, so this could be as close as we get to seeing F1 machines strut their stuff.