Correction Appended

WASHINGTON, Nov. 19 — The threat of arrest and punishment, for decades the primary tactic against drunken drivers, is no longer working in the struggle to reduce the death toll, officials say, and they are proposing turning to technology — alcohol detection devices in every vehicle — to address the problem.

In the first phase of the plan, Mothers Against Drunk Driving, backed by a national association of state highway officials and car manufacturers, will announce here on Monday a campaign to change drunken driving laws in 49 states to require that even first offenders install a device that tests drivers and shuts down the car if it detects alcohol.

Many states already require the devices, known as ignition interlocks, for people who have been convicted several times. Last year New Mexico became the second state, after Washington, to make them mandatory after a first offense. With that tactic and others, the state saw an 11.3 percent drop in alcohol-related fatalities last year.

New Mexico was not the only state to record a decline in alcohol-related motoring deaths, and several states showed even bigger drops. For example, from 2004 to 2005, Maryland showed a decrease to 235 from 286, or 17.8 percent. In New Mexico, which has had a chronic problem with drunken driving, state officials cited the new rule on interlocks as a significant factor in their campaign to cut the fatality rate. The rule did not take effect until June 17, 2005.