Luxury SUVs are hot, TrueCar's March TrueTrends report suggests. Vehicles in that category spend an average of 36 days in inventory before being sold. Subcompacts, on the other hand, don't find homes so quickly, with an average of 95 days in inventory.

This month, TrueCar says the industry wide average days in inventory is 57 days, equal to last month but 13 days above March 2010. If automakers start to have supply issues due to factories in Japan, look for inventory levels to decrease.

SUVs of all kinds continue to resonate with U.S. buyers. Luxury, midsize, small, and large SUVs snag the top four slots on TrueCar's list of 15 segments organized by shortest to longest number of days in inventory.

Small SUVs may take just 43 days, on average, to sell but the same isn't true for small cars. It'll take about 83 days for the average small car to leave the dealer lot, though we're guessing this segment will become more popular as new entries like the 2012 Ford Focus and 2012 Honda Civic eventually arrive in showrooms. On the more expensive side of the new vehicle spectrum, it appears demand for luxury vehicles is not bad, with only the luxury sport car category listed at 58 days, one day longer than the industry average for March 2011.

2011 Vehicles -- Hottest
The just-launched Lexus CT 200h hybrid hatchback is highest in demand on TrueCar's chart of the 2011 model year vehicles that sit in inventory the shortest amount of time. That car, which starts at $29,995, takes four days to leave dealer lots. The Chevrolet Volt, Audi Q5 compact crossover, and new Nissan Quest minivan followed the Lexus, lasting about 10 days in inventory before being sold.

2011 Vehicles -- Coldest
Are Kia and Hyundai about to enter a dying segment with the Sonata and Optima hybrids? That's what we're wondering as we see the Toyota Camry Hybrid at the top of the chart displaying the least in demand 2011 model year vehicles. The Toyota leads the Volkswagen Eos and subcompact Kia Rio, each of which last 114 days, on average, in inventory. Cheap, small cars fill four of the 10 spots on the list: the Mazda2 and Nissan versa last more than 100 days in inventory while the Hyundai Accent takes 96 days, on average, before being sold. The Kia Rio and Hyundai Accent may be at the end of their production lives, but we're not sure why the new-for-2011 Mazda2 is on this list. However, Hyundai's recently-launched 2011 Elantra is reportedly selling swiftly, although actual inventory data on the model was not available.