SwashSim is a traffic micro-simulation tool that employs state-of-the-art software architecture. This architecture is object-oriented and built on the C# / .NET framework programming model, which allows for a high level of extensibility and modularity. The new architecture also supports a high level of fidelity with respect to temporal and spatial modeling resolution. SwashSim uses a 0.1-second simulation time step. One of the key features of SwashSim is the ability to model individual vehicle characteristics and dynamics in great detail; thus, being able to account for the effects of roadway design features on vehicle performance with more accuracy than other simulation tools. SwashSim is intended for both research and education applications.