Six weeks after Virginia began enforcing one of the toughest drunken-driving laws in the nation, federal officials said they are finalizing plans to entice other states to follow suit, including Maryland and the District.

Virginia is one of 17 states that require first-time drunken drivers to equip their cars with interlock devices that prevent the vehicle from starting if the would-be driver has had too much alcohol. Advocacy groups have crusaded for first-conviction interlock laws because federal data show that drunken drivers involved in fatal crashes were four times more likely to have a prior DUI conviction than were sober drivers.

“We’re looking forward to getting more states to pass these laws and to getting more drunks off the roads,” David L. Strickland, administrator of the National Highway Traffic Safety Administration (NHTSA), said on Tuesday. “We think that interlocks for first-time offenders is the best overall policy. The decision, of course, is up to the states.”

There has been resistance in some state legislatures to requiring interlock use by first-time offenders. Maryland mandates them for repeat offenders and those well over the .08 percent blood alcohol level, but has not moved to require them for first-time convictions.

Now Strickland can dangle $20.8 million in highway safety funds as incentive for states to require the devices for everyone convicted of the crime.

NHTSA released new data this month showing that almost one-third of highway fatalities — 10,228 in 2010 — resulted from crashes in which alcohol use was a factor. And 70 percent of those fatal accidents involved a driver whose blood alcohol level was nearly twice the legal limit or above.

“They’re not just driving drunk. They’re driving super-drunk,” said Kurt G. Erickson, president of the Washington Regional Alcohol Program.

In addition to repeat offenders and the thoroughly drunk, Erickson said interlock programs help with the “core audience” for drunken driving, males between the ages of 21 and 35.

“It’s a group that’s proven to be resistent to run-of-the-mill campaigns,” he said. “You’ve got to hit them with a strong law enforcement message and show them that the odds are stacked against them if they make the mistake of drinking and driving.”

Montgomery County Police Chief J. Thomas Manger agreed.

“The harsher the penalty, the more the deterrent effect,” said Manger, who said he favors interlocks for first-time convictions. “The statistics show that over 40 percent of the people who are involved in drunk driving crashes are repeat offenders.”

He pointed out that almost a third of those who die in drunken-driving crashes are innocent victims, not the person who is drunk. He said there were 786 crashes in Montgomery County in 2010 in which alcohol played a role.

The cost of installing an interlock and paying for a monitoring service that sends reports to the state falls to the convicted drunken driver. Those costs vary, but $75 for installation and about $70 per month for monitoring appear to be about average.

“Folks are not going to want to incur that cost,” said John Saunders, Virginia’s highway safety director and vice chairman of the Governors Highway Safety Association. “We’ve gotten people’s attention. The word will get out. Virginia has always had very strict laws when it comes to drunk drivers.”

The NHTSA statistics show that 211 Virginians, 154 Marylanders and 5 people in the District died in 2010 in drunken-driving crashes.