Of the new Maryland laws effective October 1, 2011, it seems the law most discussed is the law (CH. 472/HB196 and CH. 471/SB424) prohibiting all forms of texting in the car as in no typing, sending or reading any kind of electronic messages.
To read more about other laws now in effect, the 90 Day Report issued by the Department of Legislative Services provides a good overview of the legislation passed as well as the legislation that did not.