Evaluation and Analysis of CFI Schemes with Different Length of Displaced Left-Turn Lanes with Entropy Method

Abstract

As an unconventional design to alleviate the conflict between left-turn and through vehicles, Continuous Flow Intersection (CFI) has obvious advantages in improving the sustainability of roadway. So far, the design manuals and guidelines for CFI are not enough sufficient, especially for the displaced left-turn lane length of CFI. And the results of existing research studies are not operational, making it difficult to put CFI into application. To address this issue, this paper presents a methodological procedure for determination and evaluation of displaced left-turn lane length based on the entropy method considering multiple performance measures for sustainable transportation, including traffic efficiency index, environment effect index and fuel consumption. VISSIM and the surrogate safety assessment model (SSAM) were used to simulate the operational and safety performance of CFI. The multi-attribute decision-making method (MADM) based on an entropy method was adopted to determine the suitability of the CFI schemes under different traffic demand patterns. Finally, the procedure was applied to a typical congested intersection of the arterial road with heavy traffic volume and high left-turn ratio in Xi’an, China, the results showed the methodological procedure is reasonable and practical. According to the results, for the studied intersection, when the Volume-to-Capacity ratio (V/C) in the westbound and eastbound lanes is less than 0.5, the length of the displaced left-turn lanes can be selected in the range of 80 to 170 m. Otherwise, other solutions should be considered to improve the traffic efficiency. The simulation results of the case showed CFI can significantly improve the traffic efficiency. In the best case, compared with the conventional intersection, the number of vehicles increases by 13%, delay, travel time, number of stops, CO emission, and fuel consumption decrease by 41%, 29%, 25%, 17%, and 17%, respectively.

Study on the location of unconventional outside left-turn lane at signalized intersections based on an entropy method

“…The calculation results of the MAPE are shown in Table 2. It can be seen that the total error between the VISSIM simulation model and the actual traffic is −2.7%, which indicates, as discussed in previous studies (Shao et al, 2019;Pan et al, 2021a;Pan et al, 2021b), that the proposed model meets the accuracy requirements of the actual project.…”

“…In order to ensure the simulation results' reliability, the model parameters were calibrated so that the outcomes were verified against the actual traffic parameters. This study follows the common model calibration procedure used in previous investigations (Shao et al, 2019;Pan et al, 2021a;Pan et al, 2021b) to calibrate the VISSIM simulation model using capacity indicators. The absolute percentage error (MAPE) between the measured capacity in each traffic direction at the intersection and the capacity in each direction in the simulation model is calculated, and the model is considered valid when the MAPE is less than 15%.…”

“…In this paper, the vehicle trajectory files generated from the simulations of the four scenarios are input into the SSAM software based on previous studies (Pan et al, 2021a;Pan et al, 2021b). The conflict threshold of the maximum time to collision (TTC) is set to 1.5 s (i.e., the traffic conflict is considered to exist when the ratio of the distance between two vehicles and the relative speed of two vehicles is less than 1.5 s).…”

Understanding the Performance of Multilane Expressway Exit Design and a Traffic Organization Strategy Based on VISSIM Micro-Simulation and a Comprehensive Evaluation Method

“…Table 3 presents the calibration results of the VISSIM model across the four investigated LOS, where the diverging ratio is about 25%, with trucks accounting for 30% of the traffic. MAPE for both capacity and density remains at acceptable levels, as previous studies have confirmed that MAPE values under 15% can provide accurate and credible guidance for engineering practice [41,42]. Furthermore, to demonstrate the accuracy of the VISSIM model, various volumes were inputted, and the density results presented in Figure 12 align with the Greenshields model, exhibiting a 99% R 2 .…”

Evaluation of Different Work Zone Road-Occupation Schemes for Monorail Construction

“…The entropy weighted method (EWM) is an objective, comprehensive evaluation method. Based on on-site survey data, we used VISSIM simulation [22][23][24] and the EWM [25][26][27] to calculate and evaluate the three schemes and selected the best scheme under different traffic volume combinations; we utilized VISSIM software to simulate various schemes. Ultimately, using the EWM, we conducted a comprehensive scoring of different schemes to determine the optimal construction organization method under varying traffic volumes.…”