The current Buick Lucerne shares its underpinnings with both the Cadillac DTS and the Chevrolet Impala, but all three vehicles are set to go their separate ways when they're refreshed in a couple years. Last month we told you that the Impala was staying FWD, and now Motor Trend is reporting that the Lucerne could still receive RWD, but it won't be as big as the DTS/STS replacement. GM is looking into the feasibility of producing a smaller Lucerne that will ride on a wheelbase several inches shorter than the 118.5-inch spread slated for the future Caddy.

The move to shrink the Lucerne will have a lot to do with stricter CAFE standards in the years ahead. MT wisely points out the fact that the Pontiac G8, which already sits on a smaller Zeta platform, shows that RWD isn't always a fuel drain. The current Lucerne is pulled with the front wheels, and gets 16/25 with the ancient 3.8-liter V6 and 15/22 with the 4.6-liter Northstar, while the smaller G8 achieves 17/25 with the 3.6-liter unit and 15/25 from the tried and true 6.0-liter pushrod. Besides the smaller Zeta's fuel economy advantages, downsizing the Buick helps keep the Caddy exclusive over the more pedestrian Lucerne.

[Source: Motor trend]