Transportraumdichte

Transportraumdichte, literally transport space density, is a proposed metric that describes how densely the available transport space is utilized within a defined area or network. It aims to capture the relationship between transport demand and the physical or capacity space that supports movement, combining spatial characteristics with flow intensity.

The concept can be applied across transport modes (roads, rail, waterways, air) and at different scales, from neighborhoods to national networks. It serves as an indicator of how efficiently space is used and how close a system is to its capacity limits. In practice, transportraumdichte reflects both supply (infrastructure, capacity) and demand (trip generation, mode choice) and can be considered in terms of space occupancy or throughput.

Calculation approaches are usually expressed in two variants. A spatial variant estimates density as the ratio of movement volume to transport space, for example V divided by A_space, where V is the number of person-trips or vehicle-h, and A_space is the effective transport area (such as road area or network area) for a given time. A capacity variant compares demand to available capacity, using T = V / C, where C is the network’s maximum moveable volume per hour. Units are commonly person-trips per hour per unit area or a unitless occupancy ratio near 0–1 (or above 1 in congested conditions).

Interpretation follows intuition: low transportraumdichte suggests underutilization, moderate levels indicate efficient use, and high values signal congestion and potential need for capacity expansion or demand management. Limitations include data requirements, multimodal interactions, and temporal variability. Applications include urban planning, congestion assessment, and resilience analysis.

See also: traffic density, capacity utilization, transport geography.