Senator John McCain and a handful of other Republicans appeared to be close March 6 to signing on to a modified proposal from Senate Democrats to raise federal fuel economy standards, according to the New York Times. An agreement would increase the measure's chances of survival as part of the Senate's energy bill. A fuel economy proposal in the energy bill was co-sponsored by Senator John Kerry of Massachusetts and Senator Ernest F. Hollings of South Carolina, both Democrats, and called for a 50 percent increase in gas mileage for the average new automobile by the 2013 model year. The proposal would require roughly the same mileage improvement by the 2015 model year as well as a trading system for greenhouse gas credits, according to people close to the negotiations. The credits could provide automakers with some leeway in reaching the goal. The compromise version would most likely also retain requirements for tougher safety standards for rollovers as well as requirements to design pickups and sport utility vehicles to be less of a threat to passenger cars during collisions, according to the Times. But it would still do away with the lower separate standards that now apply to pickups and sport utility vehicles.