A popular variant of trick-or-treating, known as trunk-or-treating

(or Halloween tailgating), occurs when "children are offered treats from the trunks of cars parked in a church parking lot", or sometimes, a school parking lot. In a trunk-or-treat event, the trunk of each automobile is decorated with a certain theme, such as those of children's literature, movies, scripture, and job roles. Trunk-or-treating has grown in popularity due to its perception as being more safe than going door to door, a point that resonates well with parents, as well as the fact that it "solves the rural conundrum in which homes are built a half-mile apart".

Source: Wikipedia