Unlike other branches of economics, time and distance are among the core factors in transport. Other branches may assume an instantaneous aspect to economic models, but in transport economics, the time it takes to travel affects the amount of transport possible in a given day. This, in turn, determines the maximum number of trips which can be made, limiting the total profit of a given transport endeavor by this constraint. The greater the distance, the greater the fuel costs and wear on transport vehicles. This too affects an individual model's overall efficiency and output.
In passenger transport, demand may peak during periods of traditionally heavy travel, such as holidays. Different transport providers, or networks, may also be competitive toward each other. Two or more competing providers may drive the consumer's costs down as they attempt to undersell each other. Lower fairs during non-peak periods may lead to higher advanced ticket purchases.
A transport network may involve additional parties. Brokers and agents are often utilized to shop for the most competitive supplier on behalf of the consumer. While these services may achieve a lower price for the transport in question, agent fees may increase the cost to the consumer. Agents may also bundle the cost of transport with those of lodging, recreation and tourism.
In many cases, a cost comparison between transport options is complicated by the availability of dissimilar goods and services to meat the consumer's needs. A traveler may book passage in car, bus, train or plane in order to reach her destination. While each of these options affords the passenger a different cost, time factors also vary according to each transportation mode. A given transport mode's actual value is then determined not just by its financial cost, but by differences between time spent and comfort experienced by the traveler.
Congestion pricing is a predetermined fee assessed by some cities in which high traffic volume potentially slows the rate of ground transport. Buses, taxicabs and other commercial cars may pay this charge directly and recuperate the cost via a surcharge to their passengers. Airports may determine the costs to the respective airlines operating within them similarly, and those airlines may then attempt to make up for the cost via higher ticket prices.