  This paper presents OTM-MPI, an extension of the Open Traffic Models platform
(OTM) for running macroscopic traffic simulations in high-performance computing
environments. Macroscopic simulations are appropriate for studying regional
traffic scenarios when aggregate trends are of interest, rather than individual
vehicle traces. They are also appropriate for studying the routing behavior of
classes of vehicles, such as app-informed vehicles. The network partitioning
was performed with METIS. Inter-process communication was done with MPI
(message-passing interface). Results are provided for two networks: one
realistic network which was obtained from Open Street Maps for Chattanooga, TN,
and another larger synthetic grid network. The software recorded a speed-up
ratio of 198 using 256 cores for Chattanooga, and 475 with 1,024 cores for the
synthetic network.
