MADD supports legislation that would make installation of such devices mandatory for all those convicted on driving under the influence. Such a bill passed thhe Senate last year only to die in the Judiciary Committee when Vallario declined to bring it up for a vote.

This year the Prince George's County Democrat has weighed  in with his own bill, but MADD isn't impressed. "It does nothing to increase the use if interlock -- let alone save lives and prevent injuries," said Caroline Cash, executive director of MADD Maryland.

Cash said she had at first been encouraged when she heard Vallario was proposing his own bill. But once interlock proponents read  the full bill, they realized there was nothing mandatory about it, she said.

MADD supports a bill called the Drunk Driving Elimination Act, sponsored in the Senate by Sen. Jamie Raskin and  in the House by Del. Benjamin F. Kramer, both Montgomery County Democrats.

Cash said MADD would raise the issue with House Speaker Michael E. Busch, who decided to retain Vallario as chairman despite protests last year from women delegates over the treatment of witnesses before the committee. She said the chairman's proposed bill isn't even as strong as the compromise legislation MADD rejected as too weak last year.

The Vallario bill would require drivers who are found to have a blood-alcohol content of 0.15 percent or more -- or those who refuse an alcohol test -- to enter an ignition interlock program in order to avert a driver's license suspension. But  Cash said that is no more than drivers are permitted to do now, adding that many drivers simply accept the suspension but continue driving anyway.

Vallario's role is crucial because as chairman he can prevent any bill he opposes from getting a vote in committee.  In practical terms only the speaker, who appoints committee chairs, has the authority to tell  him to bring a bill to a vote.