The gas-thrifty Insight got a sales boost in 2001 from the sharp spring and summer run-up in fuel prices, deliveries rising 24.8 percent from the previous year's tally. But the difference was fewer than 1000 units, and the first hybrid vehicle on American roads is still selling well below its original target of 5000 a year. And demand suddenly slacked off in early 2002, dropping 34.8 percent year-to-year for the first quarter.