The article discusses how people's daily activities influence their transportation needs. Researchers have studied two main approaches: looking at how people move around and understanding the decision-making process behind their movements. Structural models assume people make optimal choices, while behavioral models consider that people may not always make the best decisions. Structural models focus on overall population movements, while behavioral models look at individual or household behaviors. The research reviewed in the article shows that studying individual behaviors can help create more accurate models of how people choose their transportation options.