LANCASTER, Pa. (AP) _ Sen. Dan Quayle, trying to ward off complacency that might keep George Bush voters home on election day, today campaigned through Pennsylvania Dutch county, saying, ''We're not taking anything for granted.''

Quayle was on a bus tour with a series of stops at schools and rallies in the state, which is viewed as one of several close contests between Republican presidential nominee Bush and his Democratic opponent, Michael Dukakis.

''It's still seen as a battleground state. We have a slight lead,'' said Quayle adviser Ken Khachigian.

Quayle's mission was to energize voters in light of predictions voter turnout could be low and GOP worries that complacency could dash the lead that Bush has been enjoying in the polls.

Quayle was touring Republican strongholds as well as Democratic areas that supported President Reagan in 1984. ''This area is clearly a good Republican area and we're trying to beef up turnout here,'' said Quayle adviser Jim Cicconi as Quayle arrived in Lancaster.

The vice presidential candidate was joined by Sen. Arlen Specter and Rep. Bob Walker, both R-Pa., as he spoke to a gymnasium full of children and high school students at Manheim Township High School.

He urged the youths to join the fight against drug abuse and told them if they wanted to go to college, ''No one will be denied that opportunity in a George Bush administration.''

On Thursday, Quayle joked that Dukakis can't figure out what to be for Halloween - a moderate, a liberal or just himself.

''If he dresses as a moderate, he scares the liberals in his party. If he dresses as a conservative, nobody will believe it. If he comes as he is, he scares the American people,'' the Republican vice presidential nominee joked Thursday night at a rally here.

Quayle's ostensible good humor capped a rough day on the campaign trail marred by a traffic accident involving a bus in the candidate's motorcade and a school van. Later, at the rally, Quayle had to yell above the steady din of pro-Dukakis hecklers and his own supporters who were trying to shout the protesters down.

The accident en route to Bedminster, N.J., occurred when a bus carrying Quayle's mother and aunt and staff members fell slightly behind the rest of the motorcade and collided at an intersection with a school van carrying three teenagers.

Quayle later visited the emergency room where press secretary David Prosperi said the students and their driver were being treated for bumps and bruises but nothing serious.

No one in the Quayle bus was hurt.

Later, Quayle traveled to Syracuse where he encountered a disruptive audience. During the candidate's speech, a man in the front row stood, shook his finger at Quayle and shouted, even after a pair of tall Quayle supporters stood in front of the demonstrator with signs.

At one point, two Secret Service agents came down off the stage to stand within a few feet f the man, between him and Quayle's lectern on the stage. Quayle supporters yelled at the man and tried to cheer above other chanting and shouting by Dukakis supporters in the crowd.

The Indiana senator was unruffled in dealing with the situation, but interrupted his speech several times to address the demonstrators.

''We're glad to have you here and this is a free contry and you have the right to freedom of speech, but so do I,'' he said.

''Sit down and enjoy the speech. It's going to be a great one,'' he told the shouting man.

Then later, he said sternly, ''Despite what you may say, these people are going to hear what I have to say.''

The bus accident had delayed his earlier New Jersey appearance, where Quayle used a satellite speech to AT&T employees to dramatize his belief that ''America has a mission to make things work for everyone.''

He spoke at the AT&T control center for the digital long distance network and his remarks to about 2,000 employees were carried via satellite to 29 other AT&T facilties around the state.

He said the company represents the technological changes of the future, adding, ''Anyone prepared to lead us into the 1990s and then into the 21st century must be prepared to harness this change - to capture its spirit, its momentum and its excitement so that we turn challenge into achievement.

'''America is the envy of the world ... because America has a mission to make things work for everyone. We never stop trying to improve our lives to improve our sociey, to build something of value for generations that follow us,'' he said.