If cars didn't exist, people would have to rely on other means of transportation, such as bicycles, buses, trains, or their own two feet. This would obviously have a major impact on the way society functions. For one thing, cities would be much more densely populated because people would not be able to spread out as they can with cars. This could lead to more crime and pollution in urban areas. On the other hand, it might also encourage people to be more active and social since they would have to interact with each other more in order to get around. Overall, it's hard to say exactly what would happen if cars didn't exist since there are so many factors that would be affected.