1. Macro Indicators

Multimodal transportation networks rest upon the combinatory costs and performance of transport modes, or what is referred to as economies of scope. For instance, a single container shipped overseas at the lowest cost from its origin can go from road, to seaway, to railway and to road again before reaching its destination. Freight shippers and carriers therefore require quantitative tools for decision-making in order to compare performances of various transport modes and transport networks. Time-efficiency becomes a set imperative for both freight and passenger transit in private as well as in public sector activities.

Performance indicators are widely used by geographers and economists to empirically assess the technical performance (not to be confused with economic performance, for there can exist a lag between the two) of differing transport modes, in other words their capacity to move goods or passengers around. Hence, basic technical performance calculations can be particularly useful for networks’ global performance analysis as well as for modal comparison, analysis, and evaluation by bridging both physical attributes (length, distance, configuration, etc.) and time-based attributes (punctuality, regularity, reliance, etc.) of networks. Some indicators are currently used to measure freight and passenger transport. The table below gives a few of the most common ones.

Passenger-km or ton-km are standard units for measuring travel that considers the number of people traveling or ton output and distance traveled. For example, 120 passenger-km represents 10 passengers traveling 12 kilometers or 2 passengers traveling 60 kilometers, and so on. More specifically, such indicators are of great utility by allowing cross-temporal analysis of a transport nexus or given transport modes.

2. Operational Indicators

Under construction. Indicators related to specific levels of performance. Intermodal time. Reliability. Turnover. Average speed. Load factor. etc.

3. Traffic Performance

There are two major operational types of traffic influencing the capacity of modern roads, which are continuous and discontinuous traffic. The capacity of a road is the maximal hourly flow of people or vehicles that can be supported by any link. This value is influenced by three major concepts.

• Road conditions. Physical attributes of the road such as its type (paved, non-paved), number of lanes, width of lanes, design speed and the vertical and horizontal alignment.
• Traffic conditions. Attributes of the traffic using the road such as its temporal distribution and its direction.
• Control conditions. Attributes of the control structures and existing traffic laws such as speed limit, one-ways and priority.

Considering the above conditions, the capacity of a road is about 1,000 vehicles per lane per hour for continuous traffic roads and about 500 vehicles per lane per hour for discontinuous traffic roads. The operational goal of traffic planning is thus to make so that road, traffic and control conditions insure an adequate, if not optimal service. Several guidelines will favor such a goal such as wide enough lanes for a safe maximum speed in both directions and limited grades to limit speed differentials. The capacity of a road is also linked to the level of service, which is a qualitative measure of operational conditions of roads and its perception by users. The spatial distribution of bottlenecks, notably within urban areas, also have a strong impact on capacity as they are the chocking points of the whole road transport system. Traffic can be valued according to three primary measures, either the speed, the volume or the density.

• Speed is a rate of distance covered per unit of time. The average speed is the most commonly used measure to characterize traffic on a road.
• Volume is the number of vehicles observed at a point or a section over a period of time.
• Density is the number of vehicles that occupies a section at any point in  time. For example, a road section having a volume of 1,000 vehicles per hour with an average speed of 50 km/hour will have a density of 20 vehicles / km.

The critical density is the density at which the volume is maximal and the critical speed is the speed at which the volume is maximal.