What's new in Formula One for 2015

Sebastian Vettel of Ferrari drives during the F1 winter testing at Circuit de Catalunya in Spain. Photograph: Michael Regan/Getty Images

Formula One starts a new season in Australia on March 15 with a number of changes to the rules and regulations, as well as new faces in the paddock.

Check out what's different for 2015:

POWER UNITS

Kevin Magnussen of McLaren Honda. Photograph: Mark Thompson/Getty Images

Teams are now limited to four power units, each made up of six elements, per driver per season compared to five last year. Grid penalties will be applied if allowances are exceeded.

Manufacturers can continue to develop the power units during the season, according to a complicated system of tokens.

Honda are returning, as partners to McLaren, after leaving the sport in 2008. There are now four engine manufacturers.

DOUBLE POINTS

Introduced as an unloved experiment in 2014, the awarding of double points for the final race has now been scrapped.

SAFETY CAR

A 'virtual' safety car system has been introduced following Jules Bianchi's horrific accident in Japan last year, The system will allow race control to regulate speeds remotely without deploying the actual safety car.

LOOKS

Daniel Ricciardo of Red Bull Racing. Photograph: Mark Thompson/Getty Images

The fronts of the cars look different to 2014 due to tighter regulations to lower the nose while eradicating last year's ugly solutions. The result is that the cars, highly distinctive in 2014, now look more similar.

NEW FACES

Three of the drivers who will be on the Australian starting grid have not raced in Formula One before.

Max Verstappen of Toro Rosso. Photograph: Mark Thompson/Getty Images

Dutch teenager Max Verstappen, 17, will become the youngest ever Formula One driver when he debuts for Toro Rosso. His 20-year-old Spanish team mate Carlos Sainz, son of the double world rally champion, is also a new face.

Brazilian Felipe Nasr will be starting for Sauber.

OLD RACES

Mexico, with a race in Mexico City, returns to the calendar for the first time since 1992.

NEW SEATS

Sebastian Vettel of Ferrari. Photograph: Mark Thompson/Getty Images

Four times world champion Sebastian Vettel will be making his Ferrari race debut after moving from Red Bull. Spain's double champion Fernando Alonso lines up for McLaren for the first time since he left that team at the end of 2007, although he will be absent from Australia.

Russian Daniil Kvyat makes his debut for Red Bull after graduating from Toro Rosso. Sweden's Marcus Ericsson is now with Sauber after a season at now-defunct Caterham.

EARLIER STARTS

The races in Australia, Malaysia, China, Japan and Russia have been brought forward an hour as part of recommendations made after Bianchi's crash in fading light in Suzuka last October.

HELMETS

The helmet of Carlos Sainz Jnr of Toro Rosso. Photograph: Peter Fox/Getty Images

The days of drivers changing their helmet design from race to race are over. The rules now state that "in order for drivers to be easily distinguished from one another whilst they are on the track, the crash helmet of each driver must be presented in substantially the same livery at every event during a Championship season."

SPEED

The cars are faster than last year and, on the evidence of testing, Pirelli expect lap times to be about two seconds quicker and possibly even more on the softer compounds. The way that the tyres work has changed, affecting strategy and set-up.

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