The government will replace its 5-star "crashworthiness" scale of with a new, more comprehensive system. The system in place is too broad, safety advocates have said, and too many cars rate too highly, giving car manufacturers little incentive to improve their safety measures.

A formal announcement is expected later this morning, but the new official rating scale is expected to take into consideration a vehicle's ability to guard against upper leg injuries during a crash. Also, automakers and suppliers have pushed for the new ratings to highlight the benefits of electronic stability control anti-rollover technology, which the government has proposed to make mandatory on all new vehicles starting in 2012.

The new rating system is expected to be in place by 2010.