Each day, it seems, marketers go further in their quest to deliver messages so engaging and personalized that one cannot help feeling special. The latest step will be seen today in four cities when Mini USA begins delivering custom messages to Mini Cooper owners on digital signs the company calls “talking” billboards.

The boards, which usually carry typical advertising, are programmed to identify approaching Mini drivers through a coded signal from a radio chip embedded in their key fob. The messages are personal, based on questionnaires that owners filled out: “Mary, moving at the speed of justice,” if Mary is a lawyer, or “Mike, the special of the day is speed,” if Mike is a chef.

The experiment adds a new wrinkle to the wrangling among marketers and safety experts over whether drivers might be dangerously distracted by messages flashed on the growing number of digital billboards around the nation. Some communities have forced billboard owners to modify or turn off such signs, and the federal government has said it will soon publish a review of the research on the subject.

The enthusiastic guinea pigs for the Mini experiment will be more than a thousand Mini owners in New York, Miami, Chicago and San Francisco who have signed up for what the company calls “an ever-changing array of unique, personal, playful and unexpected messages.”