LIMITS OF CAPACITY OF TRAFFIC NETWORKS

Trouble free traffic flow is always dependent on the limits of capacity of the road networks, particularly where large traffic volumes arise or where unexpected disturbances occur on inter-regional roads. Capacity is defined as the highest possible traffic loading, i.e. The traffic volume per hour which a traffic lane will take under actual traffic and carriageway conditions. The author presents capacities for various road types (two-way streets, residential and service roads, motorways) and the most favourable capacity speeds, i.e. The speed values at which the highest possible capacities can be guaranteed. Junctions, t-junctions, and crossroads determine the capacity of a stretch of road, and this may be improved by traffic signals. Special events (demonstrations, performances, construction sites, accidents), result in a reduction in the capacity. The author presents some reflections on traffic capacities. He closes with a list of measures for the improvement of capacity. /TRRL/