  Studies of the effect of network structure on performance have, thus far,
been restricted to examining ensembles of synthetic networks generated by
canonical models from the Network Science literature, which do not plausibly
represent real road networks. Furthermore disparate ranges of parameter
settings for demand and supply structure are often used, making it difficult to
compare one study with another.
  To address these deficiencies, this paper proposes an experimental framework
for the design of numerical investigations to study how network performance
varies with respect to the structural properties of urban road networks. The
key step within this experimental framework is the generation of a spectrum of
ensembles of synthetic networks, which vary with respect to a single aspect of
network structure and which adhere to plausibility constraints that ensure
relevance to real urban road networks. This paper then demonstrates the
application of this experimental framework to an investigation of how two
performance indicators; the average link Volume-to-Capacity ratio and the Price
of Anarchy, vary with respect to the density of travel demand, and the size,
density and connectivity of network infrastructure. In so doing, several key
challenges of such investigations are identified, with respect to the
computational burden of the experiments and the need for empirical data on some
important aspects of network structure such as the distribution of capacity.
