Visitors to the Los Angeles Motor Show, which opens to the public today, will have a fleet of shiny new cars to ogle

Visitors to the Los Angeles Motor Show, which opens to the public today, will have a fleet of shiny new cars to ogle. But Americans are likely to breeze past the electric cars, hybrids and city runabouts and head straight for the gas-guzzlers... Cheap oil - a barrel of crude is down by 30% since June - has revived sales of big, powerful trucks and cars. The University of Michigan calculates that as a result the average fuel economy of new vehicles sold in September was 25.3 miles per gallon (10.8km to the litre), down by 0.5mpg from August. Carmakers will be rubbing their hands: bigger cars are more profitable than fuel-sippers. But the celebration will be temporary. Average economy is up by 5.2mpg since 2007 and regulations will enforce further improvement: the target is 54.5mpg by 2025.