An Investigation of Area Speed Flow Relationships by Micro-Simulation Single Links

This working paper is the first in a series relating to the EPSRC funded project, " The Definition of Capacity in Urban Road Networks : The role of Area Speed-Flow Relationships". It defines the measures collected and the methods for data collection in terms of space-time diagrams. The four measures are collected by simulating different levels of demand. Two cases are presented, the first simulates constant demand throughout each simulation period, the second simulates a demand profile which stays uniform as peak demand increases.

The paper concentrates on single link models with only one OD pair and only one route. Two equivalent networks are presented. The first represents a single link where the capacity of the link is maintained. The second is a purely hypothetical network where the capacity is reduced to zero as demand increases. This is achieved by a loop configuration so that the departure rate is affected by the queue blocking-back on itself.