Sluggish economy and high gas prices are driving consumers to prioritize fuel economy with their next car purchase, according to a new survey by the Consumer Reports National Research Center.

The survey was conducted among 1,764 random American car owners through a nationwide telephone interviews from April 28-May 2, 2011 on issues such as car buying and fuel economy.

The survey found that the average age of a car driven by most of the respondents was eight years old. The trend was common across most demographics with household income being a key factor. The average age in a household with a $50,000 yearly or higher income was six years and the average age of a car in lower-income homes was 10-years.

When asked about the next car, respondents said, many consumers expect to choose a model with much better or somewhat better fuel economy (62 percent) relative to those who are targeting about the same fuel economy (32 percent).

Survey respondents expect their next car to deliver an average of 29 mpg. Older drivers, women, and those from lower-income households expect even greater fuel economy. These demographic groups favor small cars and sedans-car types that can deliver that desired mileage. More than 10 percent said they expect 40 mpg or better in their next car, the survey found out.

Despite consumers craving relief from operating costs, and owning older cars, just 17 percent plan to purchase a car in the coming year. Younger consumers (aged 18-34 years) are three times as likely to buy a car this year as older consumers (aged 55 and over), it further said.

As America's passenger-car fleet continues to age, less than a fifth of car owners will be looking to replace their ride in the coming year, it said. When it does come time to buy, fuel economy will be a primary factor, driven by operating costs. To reach their fuel-economy goals, most shoppers will need to compromise on size and even consider paying more for a diesel or hybrid-something many consumers claim they are willing to do.