Study on the Spatial and Temporal Distribution and Traffic Flow Parameters of Non-Motorized Vehicles on Highway Segments Crossing Small Towns

The traffic flow of non-motorized vehicles on the highway segments crossing small towns is disorderly and chaotic. In order to improve the traffic environment and regulate the order of non-motorized operations, this article studies the spatial and temporal distribution and traffic flow parameters of non-motorized traffic on the highway segments crossing small towns. The non-motorized traffic within the section of the National Highway G310 crossing small towns in Henan Province, China, is investigated through various research tools such as questionnaires, interviews, and on-site statistics. The regularity and characteristics of non-motorized traffic in terms of travel purpose, travel distance, travel time, and travel frequency were obtained. Meanwhile, based on the actual collected traffic data, the speed–density relationship, flow rate–density relationship, and speed–distance relationship of non-motorized traffic flow were studied using mathematical and statistical methods. The results show that thresholds exist for both time and distance traveled by non-motorized vehicles on small town road sections. The threshold value of riding time is 30 min, and the threshold value of riding distance is 5 km. Under the free flow state, the speed distribution is near a certain desired speed, and the flow rate–density relationship conforms to the exponential function relationship when the flow rate is greater than the critical flow value. The speed and distance show a cubic function relationship, and the speed gradually increases with the increase in distance between the non-motorized vehicles and towns. Based on the results of the above analysis, it is possible to grasp the travel regularity of non-motorized cyclists on highway segments crossing small towns. This provides a theoretical basis for enhancing the efficiency of non-motorized travel and improving the non-motorized travel environment

Evaluating the Sustainable Traffic Flow Operational Features of U-turn Design with Advance Left Turn

Median U-turn intersection treatment (MUIT) has been considered as an alternative measure to reduce congestion and traffic conflict at intersection areas, but the required spacing between the U-turn opening and the intersection limits its applicability. In this paper, a U-turn design with Advance Left Turn (UALT) is proposed with the aim of addressing the disadvantages of insufficient intersection spacing and difficulty in the continuous vehicle lane change. UALT provides a dedicated lane to advance the turning vehicle out of the intersection and directly to the U-turn opening without interacting with through traffic. The effectiveness and traffic volume applicability of UALT was demonstrated through field data investigation, simulation and analysis with VISSIM software. The proposed design was evaluated in terms of three parameters: delay, queue length and the number of stops. The results show that when the traffic volume range of the main road is (1900, 2200) pcu/h and the traffic volume of the secondary road is more than 900 pcu/h, the optimization effect of UALT on both conventional intersections and MUIT is very significant. Taking a signal-controlled intersection in Zhengzhou City, China, as an example to build a simulation model, compared with the conventional intersection and MUIT, the delay drop is reduced by 73.48% and 41.48%, the queue length is reduced by 84.85% and 41.66%, and the operation efficiency is significantly improved

Evaluating the Sustainable Traffic Flow Operational Features of U-turn Design with Advance Left Turn

Median U-turn intersection treatment (MUIT) has been considered as an alternative measure to reduce congestion and traffic conflict at intersection areas, but the required spacing between the U-turn opening and the intersection limits its applicability. In this paper, a U-turn design with Advance Left Turn (UALT) is proposed with the aim of addressing the disadvantages of insufficient intersection spacing and difficulty in the continuous vehicle lane change. UALT provides a dedicated lane to advance the turning vehicle out of the intersection and directly to the U-turn opening without interacting with through traffic. The effectiveness and traffic volume applicability of UALT was demonstrated through field data investigation, simulation and analysis with VISSIM software. The proposed design was evaluated in terms of three parameters: delay, queue length and the number of stops. The results show that when the traffic volume range of the main road is (1900, 2200) pcu/h and the traffic volume of the secondary road is more than 900 pcu/h, the optimization effect of UALT on both conventional intersections and MUIT is very significant. Taking a signal-controlled intersection in Zhengzhou City, China, as an example to build a simulation model, compared with the conventional intersection and MUIT, the delay drop is reduced by 73.48% and 41.48%, the queue length is reduced by 84.85% and 41.66%, and the operation efficiency is significantly improved

Assessment of testing methods for higher temperature performance of emulsified asphalt

High-temperature features are crucial for evaluating the performance of emulsified asphalt. As effective binders, evaporation residues directly determine the high-temperature performance of emulsified asphalt. This study aims to systematically investigate the laboratory preparation process for different emulsified asphalt evaporation residues (EAERs) and proposes appropriate testing and evaluation methods. First, emulsified asphalt was prepared using five different material samples (cations M, A, L, T, and latex). Secondly, three evaporation methods were used to obtain EAERs: the direct heating method, low-temperature evaporation method, and improved evaporation method. Then, the high-temperature rheological parameters were determined using the Brookfield viscosity test, temperature-sweep test, and multiple stress creep recovery tests. Finally, microscopic test methods were adopted for the mechanism analysis, including the fourier transform infrared spectroscopy (FTIR) and the atomic force microscopy (AFM). The results show that different evaporation methods can significantly affect the high temperature performance evaluation results of EAERs. These differences are more obvious between high temperature evaporation and low temperature evaporation conditions. Moreover, the rutting resistance factor and phase angle of styrene-butadiene rubber (SBR) modified emulsified asphalt residues prepared by direct heating method present completely different change laws. From the FTIR and the AFM tests, it is found that these different change laws are due to the chemical reaction during the preparation of SBR modified emulsified asphalt residue by direct heating, which may be the aging of material or the degradation of polymer. In conclusion, the low-temperature evaporation method is recommended to prepare EAERs for a more realistic evaluation of the high-temperature performance of emulsified asphalt. The improved evaporation method should be prioritized as it further standardizes the parameters for subsequent laboratory testing

Research on High-Temperature Rheological Properties of Emulsified Asphalt Mastics and Their Influencing Factors

The high-temperature rheological properties of emulsified asphalt mastics have a significant impact on the service performance of cold recycled mixtures with asphalt emulsions. In this paper, a dynamic shear rheological (DSR) test and a multiple stress creep recovery (MSCR) test are carried out to analyze the influence of tunneling coal gangue powder (TCGP), portland cement (PC), limestone powder (LP), and four kinds of filler binder ratio (F/B) on the high-temperature rheological properties of emulsified asphalt mastics before and after rolling thin film oven test (RTFOT) ageing. Based on the principle of time–temperature equivalence and a viscoelasticity material model, the main curve of emulsified asphalt mastics under frequency scanning test is established, and the rheological properties of emulsified asphalt mastics in a wide frequency domain are analyzed. Finally, the grey entropy theory is used to quantitatively analyze the correlation between different high temperature performance evaluation indices of emulsified asphalt mastics. The results show that the RTFOT ageing process can significantly enhance the high temperature deformation resistance of emulsified asphalt residue and its mastics. The rutting factor (G*/sin δ) of emulsified asphalt mastics increases exponentially with the increase of F/B, while the phase angle is less affected. TCGP mastics and PC mastics have better high temperature performances than those of LP mastics. The most suitable range of F/B is 0.9~1.2 when TCGP is used as the filler, and 1.2~1.5 when PC or LP is used as the filler. Grey entropy correlation analysis shows that there is a good correlation between the two evaluation systems of the DSR test and the MSCR test, and both can evaluate the high-temperature performance of emulsified asphalt mastics

Motorized and non-motorized mixed traffic characteristics and lateral opening spacing calculation for the section of arterial highway through small towns

Abstract A large number of motor vehicles and non-motorized vehicles mixed in the section of arterial highway crossing the town leads to many traffic problems. Therefore, it is necessary to set up a side divider between motorized and non-motorized lanes, and the appropriate spacing of lateral crossing openings to meet the needs of non-motorized vehicles crossing the highway has become a key issue that must be resolved. This paper investigates the traffic flow characteristics of mixed traffic flow on arterial highways through small town sections, and from the two dimensions of highway access efficiency and the psychological characteristics of cyclists, it calibrates the setting range of the spacing of non-motorized lateral crossing openings under different design speeds, which is used to regulate the behavior of non-motorized vehicles crossing the street, improve the safety level of the highway, reduce the lateral interference of the highway, and improve the road access efficiency. The accuracy of the research results is verified by microscopic simulation experiments, which proves that they can meet good expectations in practical engineering. The research results have theoretical significance and reference value for improving the status quo of machine-non-mixed traffic in the section of arterial highway passing through small towns, and enhancing the efficiency and safety of highway traffic. It also provides corresponding reference for the areas facing similar problems worldwide

Compaction Characteristics of Cold Recycled Mixtures with Asphalt Emulsion and Their Influencing Factors

The objective of this study is to investigate the compaction characteristics of cold recycled mixtures with asphalt emulsion (CRME) using the Superpave gyratory compactor (SGC) method. Five characteristic parameters were proposed and calculated including the compaction energy index, the compaction energy index, three compaction energy indicators at different compaction stages. The influence of these parameters and material compositions were analyzed for the pavement performance. The difference between SGC and Marshall double-sided compaction/heavy compaction method was compared. The results show that the proposed parameters can better reflect the compaction characteristics of CRME, and the mixture effect with SGC of 50 gyrations was close to that with 75 blows using the Marshall compaction. The asphalt emulsion contents and compaction temperatures had a significant effect on compaction characteristics, but the effect of aggregate gradations was not significant. The appropriate asphalt emulsion and the new aggregate content can increase the capability of the CRME to resist the permanent deformation. The optimum mixing water content of CRME obtained by the SGC method was reduced by 18%, but the density increased by 3.5%, compared with the heavy compaction method. Finally, a new idea to determine the optimum emulsified asphalt content of CRME was provided through analyzing the compaction characteristic parameters