In May of 2016 Md Gov. Larry Hogan signed into law a bill referred to as "Noah's Law" which significantly expands the Maryland Ignition Interlock Program in an effort to reduce the incidence of drunk driving. An Ignition Interlock Device is a piece of equipment that attaches to the car and incorporates a breathalyzer that will not allow the vehicle to start if the owner blows a reading over a preset limit. The law took effect as of October 1st 2016 and changes the rules concerning who must have an Ignition Interlock Device installed on their vehicle and the length of time that the device needs to remain installed. The details of the law can be found at the State of Maryland Motor Vehicle Administration website.
To read more about the backstory to Noah's Law, named after slain Montgomery County, MD police officer Noah Leotta, check out this Washington Post article.