I would say the cars are made for 6 adults, 2 in each "row" or 3 little kids in each row. Depending on how hefty you're talking about, the bigger issue may be comfort in the depth of the seat (i.e. distance between seat and table" because you can't move either and it could be snug. If you are concerned about comfort and/or fitting in the bench style seats, you could always request one of the cars that has actual chairs.