New Compact Caddy.
Cadillac expects to have three sizes of cars next year. Reuters

Cadillac will expand its model lineup in 2012 with a new entry in the compact luxury segment codenamed ATS. General Motors released a preliminary image of model last month at the Center for Automotive Research's Management Briefing Seminars.

The small Cadillac will begin production next summer at Lansing Grand River, the same Michigan assembly plant that builds the midsize Cadillac CTS sedan, coupe and wagon. The plant received a $190 million investment and 600 jobs for the new model.

Cadillac is phasing out two of its larger sedans - the STS and the DTS - and introducing the smaller ATS in an effort the brand says will create three distinct size options for consumers. Executives used a recent Cadillac press conference in New York City to describe the move as the automotive world's version of the popular Tall, Grande and Venti sizes of coffee cups at Starbucks.

The car we code-named ATS is being developed to be a driver's car on an all-new Cadillac-specific rear-wheel-drive/all-wheel-drive architecture, the president of General Motors North America, Mark Reuss, said. We have extensively and exhaustively studied the competitive segment, and we have benchmarked the best. And when this car comes out, that will be readily apparent.