(Washington, DC — Todd Zwillich, Transportation Nation)  Commercial interstate truckers hauling cars or chickens are already banned from texting while behind the wheel. So you'd think it would be a no-brainer that rig drivers hauling gasoline or other flammable materials would be banned too.

In fact, federal rules laid down last year prohibiting texting while driving in the federally-regulated commercial trucking industry left out rigs hauling hazardous materials. Now that loophole has been closed, under planned new regulations announced by the Department of Transportation Tuesday.

In addition to the trucking ban, Obama Administration officials also said they want to lean on private companies to do more to curb distracted driving in their vehicle fleets.

Transportation Secretary Ray LaHood used the second Distracted Driving Summit to reiterate his long-held belief that distracted driving was irresponsible and potentially deadly. LaHood has spent the better part of his term at the head of DOT bringing his anti-distracted driving message to just about any open microphone he could find. On Tuesday he praised an estimated 2,200 companies and organizations that either have rules or are developing policies aimed at distracted driving.

Don Osterberg, senior vice president of trucking company Schneider National, said his company uses technology that can detect cell phone use in moving trucks. He also said employees at the company sign a "safety affirmation" before jumping behind the wheel. “The challenge to all of us is to create a national culture of safety,” he said.

More than 30 states have enacted texting or cell phone restrictions for drivers, a dozen in the last year alone, said Barbara Harsha, executive director of the Governors Highway Safety Association.

But at least one expert at the Washington DC summit wondered what use new distracted driving laws would be without tougher enforcement. Most states punish distracted driving with only minor fines. But research shows that texting is just as impairing to a driver's attention as being drunk, said John Maddox, the Associate Administrator for Applied Research at the National Highway Traffic Safety Administration (NHTSA). Maddox wondered if state distracted driving laws should be beefed up to include negligent homicide in cases where motorists are killed in distracted driving-related wrecks.

Legislation circulating in Congress now would dock states of a portion of federal highway funds if they don't enact and enforce laws against distracted driving. LaHood backs the measure.