Pedestrian motion in a crowd is influenced by social psychological factors such as culture and personal space. For example, people in Latin America tend to move closer to each other while people in North America have larger personal spaces . Irrespective of the nationality, a group of friends or a family walking together tend to maintain close proximity among them. Such prolonged proximity exhibits group behavior among pedestrians. There are two major theories on group behavior. The first considers the entire crowd as a single entity. Scholars have assumed that crowds transform individuals so that the resulting group begins to exhibit a homogeneous “group mind” that is highly emotional and irrational . The second treats everyone as independent members acting to maximize their own utility . Some researchers use a combination of the above two theories to model group behavior. For example, certain research works assume that the crowds are composed of groups, formed by individuals having relations to one another, making them interdependent to some significant degree . Studies by McPhail  and Johnson  highlights this form of group behavior in crowds. The research discussed here are based on this third approach. The method is discussed in the next section.