An effort to get more states to require convicted drunk drivers to test their breath for alcohol before they can start their cars is gaining support in Congress.

A House transportation bill unveiled Tuesday would offer additional highway funds to states that require ignition interlock devices for DUI offenders. A similar measure is expected to come before the Senate.

Fifteen states require all convicted drunk drivers, including first-time offenders, to use the devices, according to Mothers Against Drunk Driving, which has promoted use of the devices. The ignition interlock prevents a driver from starting the engine if his or her blood-alcohol content exceeds a preset limit.

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