Formula One teams will have to make engines last for two weekends and qualify and race with the same tyres next year under proposed changes outlined by the sport's governing body.
The International Automobile Federation (FIA) said today it had sent all 10 teams details of a package to make the sport safer by slowing cars down.
It said the measures were likely to be imposed if satisfactory alternative proposals had not been agreed by at least eight teams and presented to the governing body by September 6th.
FIA president Max Mosley has said speeds have become too dangerous, with Germany's Ralf Schumacher and Brazilian Felipe Massa involved in big crashes in North America last month.
Teams, under severe time constraints with the design of next year's cars, are expected to agree to the measures to prevent costs spiralling.
The proposals cover aerodynamics, tyres and engines with further measures to reduce engine power scheduled for 2006.
On aerodynamics, the FIA proposals included raising the front wing, moving the rear wing element forward and limiting the height of the diffuser.
It estimated that the measures would slow cars through fast corners while having a minimal effect on straight-line speeds.
Tyres will be limited to two sets per driver per weekend, with one set for Friday and Saturday practice and the other for qualifying and the race.