The Transportation Department said Tuesday it is prohibiting truck and bus drivers from sending text messages while operating commercial vehicles.

The prohibition, which applies to drivers of interstate buses and trucks over 10,000 pounds, is effective immediately, the department said in a statement. Truck and bus drivers who text while driving commercial vehicles may be subject to civil or criminal penalties of up to $2,750, the department said.

Nineteen states and the District of Columbia already prohibit all drivers from texting behind the wheel, according to the Governors Highway Safety Association. Another 10 states restrict texting by novice drivers.

Research by the Federal Motor Carrier Safety Administration shows that drivers who send and receive text messages take their eyes off the road for an average of 4.6 seconds out of every 6 seconds while texting, the department said. At 55 miles per hour, this means that the driver is traveling the length of a football field, including the end zones, without looking at the road, the department said.

Transportation Secretary Ray LaHood has been campaigning against texting and cell phone use while driving. President Barack Obama signed an executive order directing federal employees not to engage in text messaging while driving government-owned vehicles or with government-owned equipment. Federal employees were required to comply with the ban starting on Dec. 30, 2009.

The Transportation Department and safety advocates have also joined forces to create FocusDriven, an organization to campaign against cell phone use or texting on handheld computers while driving. The organization will be modeled after Mothers Against Drunk Drivers, which has successfully lobbied for tougher drunk-driving laws.