General Motors is cutting production at two of its North American production plants as supplies of vehicles like the Buick Regal and Chevrolet Sonic rise.

The Detroit-automaker has scheduled downtime for March 9-13 at its Orion facility outside Detroit, where the Buick Verano and Sonic are made, to adjust for lower demand, according to Automotive News, citing a "person who asked not to be identified."

The plant was also idle late last week and had scheduled a down week for April 6-10.

GM's "flex" line at its Oshawa, Ontario, plant will also be idled April 13-17, cutting production of the Cadillac XTS sedan, Chevrolet Impala, Chevy Camaro and Regal sedan, according to Automotive News.

The Regal was just picked by Consumer Reports as the better sports sedan compared to the BMW 328i.

There was a 216-day supply of Sonics on dealer lots or on the way to stores on Feb. 1, the highest inventory level since it debuted back in August 2011.  The inventory for Regal as of Feb. 1 was 213 days.

Inventory for the Camaro was 131 days, 109 days for XTS, 92 for Verano and 65 for Impala, the publication reported.

"We build to market demand," GM spokesman Bill Grotz said, without giving details, to USA Today.

The cutbacks come as car sales cool due to lower gasoline prices, which has helped increase demand for trucks and crossovers. A number of GM's nameplates are well into their life cycles and due for redesign soon anyway so the new production plans mainly affect plant workers.

Pickups, vans, SUVs sales rose 19.3 percent last month to comprise 54 percent of the market, which is up from 51.4 percent a year earlier. Car sales rose just 7.7 percent, Autodata shows.

GM has acted more quickly recently to cut production in order to avoid heavy discounts to get rid of vehicles, which hurts resale values and profits. 

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