There’s been a huge increase in the use of interlock devices after a DUI conviction. Tammy Gobert of AAA says about 9000 Virginians are now required to have the equipment. That’s up almost 90% compared to the number who were immediately put on the program when it went into effect July 1st, 2012. The interlocks make sure a driver has a clean breath test result before the engine can start. Gobert says Virginia is a leader in their use. She says the Commonwealth is among the top 15 states that have the toughest laws in that regard. Gobert says the interlock devices are effective. A federal study shows 75% of the drivers required to have one don’t get another DUI conviction.