Analytical modeling and insights, numerical experiments, and real-world tour data are used to understand the impact of congestion on urban tour characteristics, carriers’ costs, and distance/time traveled. This paper categorizes tours into three classes based on their tour efficiency and variable costs structure. Travel time/distance between customers and depot is found to be a crucial factor that exacerbates the negative impacts of congestion. Travel time variability is a significant factor only when travel time between depot and customers is considerable in relation to the maximum tour duration. For each customer, it is possible to define a dimensionless coefficient that provides an indication of the relative impact of congestion on routing constraints. Congestion also affects carriers’ cost structure, as congestion worsens the relative weight of wages and overtime escalates and the relative weight of distance related costs decrease.