WASHINGTON - President Bush encourages people to wear seat belts. Whether he routinely does so himself is not as clear. The question arose Tuesday, Bush's first full day back in town after a weekend at his ranch in Texas _ where he was spotted driving a pickup truck without wearing a seat belt.

The timing comes just as Bush's government is sending the opposite message. This week marks the launch of law enforcement's annual seat belt campaign, known as "Click It or Ticket."

In his morning briefing with reporters, White House press secretary Tony Snow was asked whether Bush wears his safety belt while riding in his armored limousine.

"Does he wear a seat belt in the limo?" Snow said in some disbelief. "I don't know."

After starting to field a question on another subject, Snow stopped to amend his answer.

"Let me just back up," Snow said. "I have seen him wear it in the limo. I'm not going to give you a report card because my ventures in the limo are relatively rare."

Later, in his afternoon briefing, Snow was asked again to clarify Bush's personal policy.

"Well, it's always important to wear seat belts, especially when driving slowly on the ranch," Snow said.

He seemed to emphasize that Bush was driving slowly when he had no seat belt on.

At the time, Bush was in his truck, pulling away from a pool of reporters who had come to watch him greet the NATO secretary-general and his wife.

"But I think it's, in point of fact, something that _ we encourage everybody to wear their seat belts," Snow added.

Citing security reasons, Snow wouldn't comment on whether the Secret Service requires Bush to wear a seat belt.

"The Secret Service, I guarantee you, looks after the president and is absolutely determined to ensure his safety in every way possible," Snow said.

Seat belt use came into national focus last month when New Jersey Gov. Jon S. Corzine sustained severe injuries during a crash. He later apologized for not wearing a seat belt.

Regular seat belt use is the single most effective way to protect people and reduce fatalities in motor vehicle crashes, according to the government.