Get on the Bus

Fifteen disparate African American men board a bus in Los Angeles bound for Washington, D.C., where they plan on attending the Million Man March. Other than their race, destination, and gender, the men have nothing in common: George is the trip organizer; Xavier is an aspiring filmmaker hoping to make a documentary of the March; Flip is an openly racist and sexist actor; Kyle and Randall are a homosexual couple; Gary, a police officer, is the sole biracial man on the bus; Jamal is a former gang banger turned devout Muslim who has evaded prosecution for the murders he committed; Evan Jr., is a petty criminal who has been permitted to break probation to attend the march on the condition that he remain handcuffed to his father, Evan Sr.
As the bus travels across country, Xavier conducts interviews with the various attendees, allowing them to express their views on race, religion, and politics. The interviews often provoke outbursts from other men on the bus, invariably leading to confrontations; the only topic of unity is the O.J. Simpson trial, with the men agreeing that, while Simpson is probably guilty, his acquittal is justified as his victims were a white woman and a Jew. Peace is kept through the various verbal arguments and physical altercations that occur by Jeremiah, the eldest member of the group. Jeremiah, an 80-year-old former alcoholic who lost his job and family, has found new meaning in life by embracing his African heritage; his philosophies on the black experience and stories of precolonial Africa serve to unite the men and ease tensions and the infighting among them.
En route the bus breaks down and the men are forced to board another bus, driven by a ethnically Jewish white man named Rick. Several of the passengers harass Rick with antisemitic remarks and jokes; Rick ultimately refuses to drive any further, citing the group's prejudice and his opposition to antisemitic remarks made by the leader of the march, Louis Farrakhan. George, himself a bus driver, accuses Rick of racism, but begrudgingly agrees to let Rick resign without incident. George takes over driving for the remainder of the trip, with help from Evan Sr.
As the bus passes through the American south, the men are surprised to find that they are greeted hospitably by several white southerners at various restaurants and rest stops. At one stop, the men pick up Wendell, a wealthy African American Lexus salesman who sees attending the march as a way to make business connections. After Wendell makes disparaging remarks about lower-class African Americans, the rest of the men forcibly eject him from the bus and abandon him on the side of the road.
In Knoxville, Tennessee, the bus is pulled over by a pair of racist state troopers, who accuse the men of using the bus to smuggle drugs. The bus and its passengers are checked by a drug-sniffing police dog, turning up no evidence of drugs; the troopers then allow the bus to resume its journey.
As the bus nears Washington, Jeremiah passes out and is rushed to a hospital. The doctors there discover that Jeremiah is suffering from advanced coronary artery disease, which made the stress of the trip potentially deadly for him. Evan Sr. and Jr., Gary, Jamal, and Xavier opt to stay with Jeremiah at the hospital and watch the march on television while the rest of the men leave in the bus to attend. Shortly after they leave, Jeremiah dies. The rest of the group returns to the hospital, saying that, to stay true to the spirit of the March, they chose not to attend the march but to return and be with Jeremiah.
As the bus prepares to return to Los Angeles, the men find a prayer that Jeremiah wrote with the intention of praying it when the bus arrived at Washington, D.C. The men drive to the Lincoln Memorial, where George leads the men in Jeremiah's prayer, and Evan Jr. and Sr. remove their handcuffs.

Question: What do the state troopers think the bus is doing?
Answer: smuggling drugs