Search Results (4)

When build–operate–transfer (BOT) roads are transferred back to the government upon the expiry of their contract, they are typically considered to be public roads and are no longer subject to tolls. However, in China, BOT roads, after being transferred to the government, remain tolled by the government in order to maintain efficiency. Therefore, such roads are termed public toll roads (PTRs). During the operational phase of PTRs, ongoing operating costs become a significant financial burden compared to the initial investment made for their construction. Against the backdrop of global carbon emission efforts, this paper studies the operational strategy of PTRs in terms of car emission costs, which constitute a portion of PTRs’ operation costs. This paper explores the operational strategy of PTRs, including whether the government should operate the road independently or outsource their operation to a competent private firm. Our analysis concludes that the operator should manage PTRs for the entire duration of their operation by maintaining self-financing while also accounting for operation costs. In this study, governmental regulations for the cost of carbon emissions are also studied. Full article

Efficient and sustainable transportation is crucial for addressing the environmental and social challenges associated with urban mobility. Accurate estimation of travel time plays a pivotal role in traffic management and trip planning. This study focused on leveraging machine learning models to enhance travel time estimation accuracy on toll roads under diverse traffic conditions. Two models were developed for travel time estimation under a variety of traffic conditions on the Don Muang Tollway, Bangkok, Thailand: a long short-term memory (LSTM) recurrent neural network model and a support vector regression (SVR) model. Missing data were treated using the proposed segment-based data imputation method. Unlike other studies, the effects of missing input data on the travel time model performance were also analyzed. Traffic parameters, such as speed and flow, along with other relevant parameters (time of day, day of the week, holiday indicators, and a missing data indicator), were fed into each model to estimate travel time on each of the four specific routes. The LSTM and SVR results had similar performance levels based on evaluating the all-day pooled data. However, the mean absolute percentage errors were lower for LSTM during peak periods, while SVR performed slightly better during off-peak periods. Additionally, LSTM coped substantially better than SVR with unusual traffic fluctuations. The sensitivity analysis of the missing input data in this study also revealed that the LSTM model was more robust to the high degree of missing data than the SVR model. Full article

With the current popularity of mobile devices with Bluetooth technology, numerous studies have developed methods to analyze the data from such devices to estimate a variety of traffic information, such as travel time, link speed, and origin–destination estimations. However, few studies have comprehensively determined the impact of the penetration rate on the estimated travel time derived from Bluetooth detectors. The objectives of this paper were threefold: (1) to develop a data-processing method to estimate the travel time based on Bluetooth transactional data; (2) to determine the impact of vehicle speeds on Bluetooth detection performance; and (3) to analyze how the Bluetooth penetration rate affected deviations in the estimated travel time. A 28 km toll section in Bangkok, Thailand, was chosen for the study. A number of Bluetooth detectors and microwave radar devices were installed to collect traffic data in October 2020. Five data-processing steps were developed to estimate the travel time. Based on the results, the penetration rate during the day (50 to 90 percent) was higher than during the night (20 to 50 percent). In addition, we found that speed had adverse effects on the MAC address detection capability of the Bluetooth detectors; for speeds greater than 80 km/h, the number of MAC addresses detected decreased. The minimum Bluetooth penetration rate should be at least 1 percent (or 37 vehicles/h) during peak periods and at least 5 percent (or 49 vehicles/h) during the off-peak period. Full article

The usage of Ground Tire Rubber (GTR) in asphalt pavements has gained renewed interest due to its potential sustainability, economic, and performance benefits. This study focuses on asphalt mixtures designed with three different rubber modifier products including (1) a terminal-blend GTR, (2) a dry-process, chemically processed rubber product, and (3) a terminal-blend rubber-polymer hybrid product. The modifications were incorporated into Illinois Tollway’s approved Stone Matrix Asphalt (SMA) designs using (1) a base binder (PG 58-28), (2) a softer binder (PG 46-34), and (3) a softer binder with higher recycled content. Disk-shaped Compact Tension (DC(T)) test, Hamburg Wheel Tracking Test (HWTT) and Acoustic Emission (AE) tests were performed to characterize the mixtures. The fracture energy for most mixtures met the stringent criteria of 690 J/m² and the rut depths measured were less than 6 mm at 20,000 wheel passes. A Hamburg-DC(T) plot suggests that higher amounts of RAP/RAS (RAP: Reclaimed Asphalt Pavement; RAS: Reusable Asphalt Shingles) can be successfully used if a suitably soft base binder is employed. Full article