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A Framework For New Generation Transportation Simulation, Daiheng Ni
A Framework For New Generation Transportation Simulation, Daiheng Ni
Daiheng Ni
This paper discussed the evolution and future trend of simulation in general domain and in transportation. Some challenges facing transportation modeling and simulation were identified. As an effort to address these challenges, a framework of new generation transportation simulation was developed. The framework is envisioned to be multi- scale in resolution, parallel in execution, and driven by ob- jects. The paper further discussed strategies of transporta- tion simulation at a nanoscopic level which offers a level of modeling detail beyond the state-of-the-art.
Direct Methods Of Determining Traffic Stream Characteristics By Definition, John D. Leonard, Daiheng Ni
Direct Methods Of Determining Traffic Stream Characteristics By Definition, John D. Leonard, Daiheng Ni
Daiheng Ni
There are generally two approaches to derive traffic stream characteristic s (i.e. flow, space mean speed, and density): indirect approach which derives traffic stream characteristics by estimation from correlated variable(s) and direct approach which determines traffic stream characteristics by definition from field observations. A method of the former approach inevitably involves estimation error while a method of the latter provides “the ground truth”. This paper examines and contrasts three direct methods, namely the HCM method, the x-t method, and the n-t method. The HCM method determines traffic stream characteristics based on their definition adopted by Highway Capacity Manual (HCM). The …