How automakers, car buyers are responding to low gas prices

Since last year’s Detroit Auto Show, gas prices have dropped by nearly a third. With the new lower prices, demand has gone up for big new SUVs and sedans, but automakers have also switched gears to develop more fuel-efficient cars. Gwen Ifill speaks with John Stoll of The Wall Street Journal about the tension between the two trends and convincing car buyers to think long-term.