Formula One has re-written the rule book this season with the cars looking very different to last year and the drivers' title to go to the man who wins most races rather than most points.

Red Bull technical supremo Adrian Newey, who designed title-winners for McLaren and Williams, has said the technical changes are the most significant since flat-bottomed cars were first introduced in 1983.

The following looks at the main novelties, as well as their likely impact on the racing:

Points

The driver who wins the most races will be champion, even if someone else scores more points.

If two or more drivers end the season with the same number of victories, the championship will be decided by total points scored based on the existing 10-8-6-5-4-3-2-1 system.

Aerodynamics

The major and most visible area of change.

- Most add-on aerodynamic elements (winglets, barge-boards, turning vanes and chimneys) have been stripped off the cars, introducing a cleaner look.

The aim is to facilitate overtaking by making a car less susceptible to turbulence when a driver gets close to one in front.

- Rear wings are narrower and higher than in the past, designed to reduce the effect on a following car.

- Front wings are lower and wider (the same width as the car) with driver-adjustable flaps controlled from the steering wheel. Drivers are allowed to make two adjustments per lap over a six-degree range.

Engines

Drivers are restricted to eight race engines each per season, plus four per team for testing, in a move to cut costs. The rules state that "should a driver use more than eight, he will drop 10 places on the starting grid at any event during which an additional engine is used". There are 17 races this season.

However drivers may use their engines in any sequence they choose, unlike last season's requirement for them to be used for two races in a row, which opens up new strategic challenges.

Rev limits have been reduced to 18,000 rpm from 19,000 to increase reliability.

Kers

Not an obligatory part of the regulations, and most teams will not be using their systems until they are convinced about reliability. That could lead to an early situation of haves and have-nots.

The Kinetic Energy Recovery System recovers the normally wasted kinetic energy generated by the car's braking process and stores it either in an electrical battery or a flywheel.

The driver can then press a 'boost' button on the steering wheel, releasing an 80hp burst of energy for a maximum of 6.7 seconds.

However the weight and packaging of the system also has to be taken into account.

"KERS in 2009 could be worth between 2/10ths and 3/10ths of a second per lap," says Williams technical director Sam Michael. "However, once aero performance converges, KERS could start to become a greater performance differentiator.

"If the regulations give more scope to the technology, it could be worth anything up to a second a lap and it will be needed to win grands prix (in the future)."

Tires

A return to slicks (treadless tires) after 11 years with grooved ones. The aim is to put the emphasis on mechanical grip rather than aerodynamics.

Grip is expected to increase by 20 percent, worth about two seconds a lap depending on the compounds used, but the performance gains will be countered by the effect of the new aerodynamic regulations.

Testing has already shown however that some cars have a problem with the weight distribution and rear tires 'going off' faster than the front ones.

Testing

Banned from this week until Dec 31, but teams will be allowed to carry out three one-day young-driver training tests after the end of the season.

Those drivers will be eligible providing they have not competed in more than two grands prix in the previous two years or tested a F1 car on more than four days in that period.

Teams may also carry out eight one-day straight-line aerodynamic tests between Jan. 1 and the end of the season.

Safety car

The rule that led to drivers being penalized for pitting during the early stages of the safety car being deployed has been ditched.

Instead, new software has been introduced to regulate the speed of drivers returning to refuel, a move that allows the pits to stay open.

(Reuters via China Daily March 19, 2009)