A new control-oriented METANET model to encompass service stations on highways

TL;DR

A second-order macro-scopic traffic model that, compared to the classical METANET, incorporates the dynamics of service stations on highways, and employs the (so-called) store-and-forward links to model the stop of vehicles and the possible queue forming in the process of merging back into the highway mainstream.

Abstract

In this paper, we propose the METANET with service station (METANET-s) model, a second-order macroscopic traffic model that, compared to the classical METANET, incorporates the dynamics of service stations on highways. Specifically, we employ the (so-called) store-and-forward links to model the stop of vehicles and the possible queue forming in the process of merging back into the highway mainstream. We explore the capability of the METANET-s to capture well both traffic back propagation and capacity drops, which are typically caused by the presence of vehicles joining again the mainstream traffic from the service station. Therefore, capturing these effects is crucial to improving the model's predictive capabilities. Finally, we perform a comparative analysis with the Cell Transmission Model with service station (CTM-s), showcasing that the METANET-s describes the traffic evolution much better than its first-order counterpart.

Figures (4)

• Figure 1: Link discretization of a freeway stretch in METANET model
• Figure 2: Depiction of the model. The freeway links (pink rectangles) represent the mainstream and on-ramp/off-ramp of service station which are connected by the nodes (black dots), an origin link (blue rectangle), a destination link (brown rectangle), and the is modeled via a link (green rectangle).
• Figure 3: Back propagation phenomenon resulting from congestion, hence $\rho_{s_{2}}>\rho_{\textup{cr},s_{2}}$ at the off-ramp of the $s_{2}$. (a) the flow of $q_{\textup{st}}(k)$ and density of $s_{2}$$\rho_{s_{2}}(k)$, (b) flow of on-ramp $s_{1}$$q_{s_{1}}(k)$, queue length of vehicles in $\ell_{\textup{st}}(k)$, (c) flow of $m_{1}$$q_{m_{1}}(k)$, density of link $s_{1}$$\rho_{s_{1}}(k)$, (d) the flow and density in $m_{2}$, i.e., $q_{m_{2}}(k)$, $\rho_{m_{2}}(k)$.
• Figure 4: Capacity drop captured in the in comparison with the flow variations captured by the model of at On-ramp merging location: flow and density trajectories for links $m_{4}$,$m_{5}$, and $m_{6}$ in and flow captured by ($\phi(k)$) of cells $m_{4}$,$m_{5}$, and $m_{6}$ respectively in (a), (b), and (c).