01628906

Component

In this study, the authors define first-in, first-out (FIFO) and unifiable properties in a multi-lane traffic flow system constructed by relations among lane and total flow-rates, densities, and speeds. Then the authors derive a general form of non-FIFO unifiable lane-based fundamental diagrams, which is composed of three components: lane density proportion, total traffic fundamental diagram, and lane speed ratio, with two constraints. In addition, the authors present an analytical discussion on the construction of the non-FIFO unifiable lane-based fundamental diagrams on a two-lane road segment. The findings infer that (i) the lane speed ratios can be constant, dependent of the total density, lane density proportions, and both of them without violating the constraints; (ii) adding high-order, piece-wise, and interaction terms can be three potential strategies to extend and improve the basic linear lane speed ratio models in the empirical study. In the calibration of non-FIFO unifiable lane-based fundamental diagrams in near-steady states, the authors first apply an effective method to identify nearstationary states from VDS 30-sec raw data, and further extract near-steady states. Then the authors empirically verify the existence of the total fundamental diagram. The results show that the total flow-rate is significant to the total density in both free-flow and congested regimes. In addition, the authors build and fit nine models (Mod0 - Mod8) for lane speed ratios, and compare their performances by F-test, adjusted R², Mallow’s C<sub>p, and BIC. The results show that Mod5 (piecewise linear regression model) and Mod8 (multiple linear regression model with a subset of interaction terms) perform the best. Finally, the authors validate the calibrated non-FIFO unifiable lane-based fundamental diagrams. The results show that both of the constraints are approximately satisfied and the calibrated functions and fitted models fit the near-steady states well. In sum, the authors can conclude that our derived lane-based fundamental diagrams are theoretically well defined, physically meaningful, and empirically well fitted.

This paper was sponsored by TRB committee AHB45 Standing Committee on Traffic Flow Theory and Characteristics.

01618707

17-06632

English

18p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Calibration; Multilane highways; Traffic flow theory; Traffic models; Validation

First-in-first-out systems

Highways; Planning and Forecasting

Transportation Research Board Annual Meeting 2017 Paper #17-06632

TRIS, TRB, ATRI

Dec 8 2016 12:43PM