Elizabeth Obad's son was killed nearly 16 years ago by an impaired driver.

The Blasdell resident turned her grief into a passionate fight for tougher drunken driving policies and, on Wednesday, fought back tears as she talked about the long battle to see Leandra's Law become reality.

The state legislation, officially know as the Child Passenger Protection Act, passed last November but takes full effect Sunday.

The measure requires that individuals convicted of driving while intoxicated, aggravated DWI, or driving with a blood alcohol content over 0.08 percent must have an ignition interlock device installed in their vehicle for at least six months.

Beforehand, ignition interlock devices were mandatory for convictions in which a driver had a blood-alcohol level above 0.18 percent.

The law also makes it a felony for anyone over the legal blood alcohol content to drive with a child under the age of 16 in the car, a portion of the law that has been in effect since Dec. 15.

"This is going to save lives. If we can't stop drunk drivers, then let's stop their cars," Obad said at a demonstration of the ignition interlock system at the offices of O'Brien Boyd attorneys in Williamsville.

New York became the 12th state to enact mandatory ignition lock devices for drivers convicted of any level of drunken driving.

Convicted drivers must pay the $70 installation fee and $70 monthly cost for the devices, which require them to blow into a Breathalyzer-type device to operate the car.

Passage of the legislation came after several high-profile accidents, including a 2009 crash in Manhattan that killed 11-year-old Leandra Rosado, whom the bill was named for following a personal lobbying campaign by her father.

In Obad's case, her 26-year-old son, George, a Marine Corps sergeant, was killed when he rode as a passenger on a friend's motorcycle while he was stationed in Newburgh. Tests later revealed that the friend had a blood alcohol level of .15.

The roads were slick from rain, the friend lost control of the motorcycle and the two were killed instantly.

"I've wanted something like this law for a long time," said Obad, who is president of Mothers Against Drunk Driving in Erie County.

An alcohol ignition interlock is a device about the size of a cell phone that is installed in a vehicle's ignition system. A driver must blow into the device, and the vehicle will not start if drivers have measurable alcohol set to a predetermined level in their blood system.

Interlocks also may be set for "running retests," which require a driver to provide breath tests at regular intervals. That feature prevents them from asking a sober friend to start the car. If a driver fails a running retest, the vehicle's horn will honk, and/or the lights will flash to alert police.

For safety reasons, the interlock does not have the ability to stop the vehicle once it is running.

Driving a vehicle without an interlock device after one has been ordered is a Class A misdemeanor, punishable by up to one year in jail, as is assisting someone in circumventing an interlock device.

Newer interlock devices come equipped with tiny cameras to document their use, said John Fasciana of Ignition Interlock of Erie County, a company that installs the devices.