Upgrade Section Research Articles

What causes severe truck crashes on the flat and mountainous expressways? A comparative study in China

ABSTRACT The severity of collisions involving heavy trucks exhibits a difference between the flat and mountainous expressways. Based on 1,175 records of truck crashes from 2015 to 2020 on two typical expressways in China, a heteroskedastic ordered probit model was applied to determine the significant factors among driver-vehicle-roadway-environment interactions and their marginal effects on the collision severity outcomes. The modeling results demonstrated that some variables (i.e. speeding and risky following behaviors of drivers, existence of curves and downgrades, adverse weather, etc.) are significant predictors of truck crashes on both flat and mountainous expressways. In contrast, some variables were significantly correlated with truck crashes on only the flat expressway (upgrade section) or the mountainous expressway (involvement of multiple vehicles, truck’s overloading status, nighttime period). The findings, taken collectively, may be valuable as a reference for drafting traffic rules and implementing technical solutions to ensure a safer traffic environment for heavy trucks on expressways.

Concentrating photovoltaic/thermal collectors coupled with an anaerobic digestion process: Dynamic simulation and energy and economic analysis

This work presents a dynamic analysis of an anaerobic digestion plant, in which concentrating photovoltaic/thermal collectors are used to match a part of both heating and power demand of the process. The system is supplied by the organic fraction of municipal solid waste. The system also includes a thermal storage tank and an auxiliary heating system. An up-grade section is also included, to produce biomethane, suitable for injection into the natural gas pipeline network.For such hybrid solar-biomass system, a comprehensive simulation model was developed in MATLAB®, calculating the time-dependent production of biomethane as a function of the operating temperature within the digester. The model, based on differential equations and thermal balances, accounts for both thermal and biological phenomena occurring within the process, taking into consideration the geometrical and structural characteristics of the system. The consistent Anaerobic Digestion Model 1 is used to model the biological process, evaluating the biogas production as a function of a series of operating variables: the digester operating temperature, mass flowrate and temperature of the hot water entering the digester, ambient temperature, mass flowrate and composition of the organic waste in input. The model also calculates the electric consumption of the upgrading process, used to convert the biogas into biomethane. Such model was integrated into the simulation platform of the overall plant, developed in TRNSYS, evaluating the energy, environmental and economic performance of the entire system. A case study is presented, showing the dynamic performance of the system under evaluation: for such case, a primary energy saving of 24% was found, with respect to a conventional digester; around 20% of the overall thermal energy demand is met by solar energy; finally, a promising payback time of about 3 years was estimated.

Occupational risk assessment of the impact of a heating microclimate in conditions of modernization of a metallurgical enterprise

Introduction. A controlled environment is the most significant industrial conditions factor, which predominantly affects the well-being, working capacity, and employees’ health. The objective of this research was the scientific justification of the need for prevention of the upgraded sections of the metallurgical enterprise related to the impact of the heating-controlled environment by results of an estimation of the occupational risk. Results. The workplaces of the occupations under study were characterized by a heating-controlled environment. Under hygienic criteria, working conditions in most workplaces corresponded to hazardous ones and formed the pathology risk from low to very high (Classes 3.1-3.4). Overall, the enterprise usually registered a small degree of the relationship between the identified health disorders and the heating-controlled environment. Still, the morbidity of diseases of the ear, skin, and urogenital apparatus fulfilled the criteria of industrial conditionality, with an average degree with its influence. Male patients with high blood pressure and females with diseases of the digestive system were identified to show the significant-high incidence. Moreover, there is a high and medium degree of association of diseases of the digestive system and skin with exposure to heat radiation in women and men, respectively. Exposure to heat radiation at controllers raised the risk of developing gynecological abnormalities, as well as complications of pregnancy, childbirth, and the postpartum period by 3.4 times (very high degree of association) and 3.0 times (high degree), respectively. The relative risk of mortality owing to circulatory diseases was 3.3 in occupational groups of lehr operators, 2.8 in blacksmiths, and 1.8 in melters requiring the development of targeted prevention programs.

The impact of road investment projects on the economic activity in the light of companies operating in surrounding environment

The aim of this research was to determine the impact of road investment projects on the economic activity of the enterprises operating in the surrounding environment, using two road projects located in Poznań and Lublin as an example. The research material was collected applying the technique of pen-and-paper personal interviews (PAPI). Standard measures of descriptive statistics and nonparametric tests were employed in the statistical analysis. Most often only small groups of respondents indicated positive effects of the investment project. The results concerning the time of travel on the upgraded sections of the road, which showed a greater tendency to the positive rating of the investment project are the exception. Moreover, statistically significant differences in the perception of the road depending on the investment project location were observed. The research showed that the impact of the investment project on the economic activity in the surrounding environment was more visible in the case of the S19 road than the DK92 road. The investment project’s impact measured in travel time terms was found to be considerably more extensive than the one evaluated on the basis of the economic activity or the annual turnover.

The role of risk and assumption in the engineering geology of Crossrail

The Crossrail project is a new underground railway running east–west through the heart of London. It will connect with 110 km of new or upgraded sections of surface rail to Reading, Shenfield and Abbey Wood. Crossrail co-ordinated ground investigations for the central tunnelled sections began during the 1990s and continued to 2011 according to a strategy that was based on a review of other major tunnelling projects and best practice. The level of detail in the investigations varied according to local geological complexity and design requirements. However, the state of knowledge on the geological structure is hampered by London's long history, leading to assumptions on the level of complexity or simplicity. Drift-filled hollows and Lambeth Group sand channels were known features presenting risks to excavations but relationships with faulting were unknown or unproved. The emerging geological knowledge was developed through multiphase investigations and collation of third-party data to allow far-field considerations. The risk profile for tunnel boring machine tunnels is lower than that for sprayed concrete lined tunnels but the risk for both increases with increasing proximity to pre-existing infrastructure. Ground movement assessments become critical and mitigation of movements can be significantly affected by unexpected variations in ground conditions.

Groundwater monitoring of the deep aquifer for the construction phase of the Crossrail project

The Crossrail project is a new underground railway through the heart of London. It will connect with 110 km of new or upgraded sections of surface rail to Reading, Shenfield and Abbey Wood. The route runs through typical London Basin geology. Ground investigations began during the 1990s and continued to 2012. A total of 1314 groundwater monitoring devices were installed and monitored at regular intervals. The groundwater monitoring strategy adopted by the project in preparation for and during construction included (1) establishment of a robust baseline and system for measuring changes to the baseline, (2) establishment of a series of sentinel wells to monitor any possible migration of third-party contamination sources and provide advance warning for construction dewatering sites and (3) performance of pumping tests. The sentinel wells were located to provide sufficient time to allow mitigation measures to be put into place without cessation of construction dewatering, thereby minimizing risk to the project. The pumping tests were carried out to demonstrate constructability, aid in the design of construction dewatering systems and provide support for the consent submissions on the impact of dewatering. Instrumentation was transferred to, and monitored by, the construction contractors but data were collated centrally by Crossrail. Contractors added their own instruments located either within or immediately adjacent to the structure to confirm dewatering levels or risk of base heave. The data were used for regular reporting to the Environment Agency in support of the dewatering permits and ensuring no interruption of supply to licensed abstractors.

Regional-scale groundwater investigations for the Crossrail project

The Crossrail project includes a new underground railway through the heart of London. It will connect with 110 km of new or upgraded sections of surface rail to Reading, Shenfield and Abbey Wood. Ground investigations for the central tunnelled sections began during the 1990s and continued until 2011 according to a strategy that was based on a review of other major tunnelling projects and best practice. The level of detail in the investigations and subsequent groundwater monitoring varied according to local geological complexity and design requirements. A total of 1019 boreholes were drilled to a maximum depth of 114 m and contained a total of 1314 piezometers. Of these, 233 piezometers were installed during the 1990s and 1081 piezometers and several other monitoring types were installed in the following phase during the 2000s. The ground and groundwater investigation strategy included the following: (1) groundwater monitoring to accurately determine the multiple aquifer regional groundwater regime with varying underdrainage, in the west; (2) tidal monitoring in the east, where an unconfined single aquifer system predominated; (3) investigation of the impact of local features (e.g. fault zones and scour features); (4) determination of long-term groundwater trends. Crossrail data were supplemented with third-party data to provide more information on the far field and provide more definition on larger scale geological structures (e.g. faulting at Farringdon and Limmo). Installation trials were conducted on several types of installation, and their performance for monitoring multiple aquifers, in particular during permeability tests, is discussed. For large projects such as Crossrail, long-term performance of groundwater monitoring installations is critical for establishing a baseline in addition to obtaining information for design. Annual reviews of data backed up by remediation works allowed many installations to provide reliable groundwater data for up to a decade prior to the construction phase.

Representation of Sag Bottleneck Phenomena with a Commercial Microscopic Traffic Simulator

Abstract Sag sections, which are road structures comprising a downgrade section followed by an upgrade section, frequently become a bottleneck on freeways. It is therefore highly desirable to devise methods of mitigating traffic congestion in sag zones by means of vehicle-to-vehicle (V2V) or Vehicle-to-X (V2X) communications technologies as well as through improvement of road alignment. Simulation-based investigation is a useful measure for identifying the optimal control scheme for connected and autonomous vehicles prior to field experiments. Indeed, microscopic traffic simulators representing sag bottlenecks have been developed, but these were constructed for the purpose of a single research project, which is not a cost-efficient approach. If sag bottleneck phenomena could be faithfully represented by way of a commercial microscopic traffic simulator, more research attention would be attracted to this issue. In this contribution, we present a process by which sag bottleneck phenomena can be represented with one of the most popular commercial microscopic traffic simulators, VISSIM, which allows the longitudinal gradient of a freeway sag section to be set as a control variable.

Analysis on Sag Bottleneck Phenomena Based on Multiclass Traffic State Estimation

Abstract This study proposes a novel technique for analyzing traffic dynamics based on multiclass traffic state estimation. One of the most common causes of bottlenecks on Japan’s roads are sags. Considerable scientific attention has been paid to the bottleneck phenomena at sags in terms of both their microscopic and macroscopic aspects. However, the mechanisms of traffic breakdown at sags are not understood in detail yet. This paper presents a data assimilation system using a particle filter in which online observations from fixed detectors and probe vehicles are combined with multiclass traffic flow simulations to analyze the traffic dynamics that contribute to congestion at sags. The application of a particle filter enables the monitoring of the hidden traffic state described by the unobservable parameters of traffic flow models. On the application of this method to an existing sag bottleneck section, we found that i) the estimation results are a good fit to observation data from both fixed detectors and probes, ii) the integrated use of multiple data source enables estimation accuracy to be improved, iii) the traffic capacity of the upgrade section is lower than that of the other sections and this tendency is more marked for heavy vehicles than for regular vehicles.

Human activities and coastal erosion on the Kien Giang coast, Vietnam

By 2009, the Kien Giang coast, Vietnam, had experienced significant coastal erosion and mangrove degradation. Recent mitigation strategies, developed through policies, plans and mangrove planting programs have not been successful, in part because the causes of coastal erosion were not adequately identified. This paper investigates the relationship between human activities and coastal erosion in Kien Giang province. This study used mixed methods to understand the causes of coastal erosion with an emphasis on human activities. In this investigation, local communities were involved as co-investigators to explore the causes of coastal erosion in Kien Giang province. While natural factors (adverse effects of climate change and sea level rise) have been widely reported as main causes of coastal erosion, human activities initially were not recognised by local communities as significant contributors to coastal erosion and mangrove degradation. Human activities such as poor aquaculture pond construction, poor construction of new and upgraded sections of the sea dyke system, mangrove afforestation using only a single species, mangrove cutting for commercial and domestic uses, and construction of local boating channels, and the interaction of anthropogenic activities and physical processes are significant contributors to erosion. The study resulted in the awareness of the impact of community activities on the coast being improved. Knowledge gaps and necessary policy changes are identified.

Traffic Conflict Technique-Based Setting Method of Freeway Climbing Lane

Speed of heavy vehicles is greatly reduced on upgrade sections due to their insufficient climbing capability, thus having great impact on traffic safety. Setting climbing lanes can solve this problem effectively. Considering China’s traffic composition and operational status, this paper proposed the traffic conflict technique-based setting method of freeway climbing lanes in order to set foundations for climbing lanes with the goal of promoting traffic safety. Based on large freeway upgrade section data and actual traffic characteristics, the paper built simulation models with VISSIM. 220 schemes were simulated by setting different road and traffic conditions of models. The paper then used Surrogate Safety Assessment Model (SSAM) to calculate traffic conflict, analyzed the influence of slope, slope length and mixed rate of heavy vehicles on traffic safety on upgrade sections. Finally, taking the reduction extent of the collision rate after setting climbing lanes as an indicator, this paper used K-means to classify the effectiveness level of the climbing lanes. The paper found the setting position and basis of the climbing lanes. The findings of this paper can provide support to effective decision making with regards to constructing future climbing lanes.

Pulp mill fly ash for stabilization of low-volume unpaved forest roads — field performance

Increased temperatures and rainfalls will give more settlements and less bearing capacity in gravel roads, which will have implications for the forestry. Pulp mill fly ash without additives was used for stabilizing the road base of a low-volume gravel road. A two-year monitoring of the road was conducted, including measurements of achieved ash content, density, water infiltration capacity, and load bearing capacity. The results showed that the ash-stabilized sections performed better than conventionally upgraded sections and also achieved increased bearing capacity over time. Hydration of the fly ash increased the stiffness and decreased the permeability of the road base. The differences were more pronounced during spring thaw. Best performance was achieved in the section with thicker ash stabilized layer.

Influence of Construction of Railway Superstructure on Railway Quality

The operation of railway tracks is historically confirmed that the classic structure of the railway superstructure is capable to ensure operational capability of standard railway tracks for a relatively long period of time (railways tracks to speed of 160 km.h-1). Such a railway track and its track is considered the railway track with a classic structure of the railway superstructure, where track removal is stored in the ballast. In the case of high operating and axle load, increasing track speed and requirements for safety of operation, which are associated with high requirements on the track geometry, it appears that such structure has its operational (in terms of guaranteeing the long-term safety and reliability of the railway track) and economic (in terms of the cost of maintenance of railway track) limits. "Floating" placement of the track removal during each passage of a rail vehicle, or train leads to the growth of dynamic horizontal and vertical forces that cause gradual degradation of track geometry, what subsequently leads to restless journey of moving rail vehicles. Elimination of imperfections in track geometry - the quality of the railway track - forces the operators to remove such imperfections of railway track in time and financially consuming maintenance work in certain periods. However, it is sufficient if only the weakest element of classic railway superstructure is replaced in the railway, and it is the track ballast using other more appropriate component representing no elastic and plastic behaviour. The structure is such replacement, in which the track removal is concreted (monolithic structure) or stored on a concrete or asphalt bearing layer (layered structure), namely structural design, which is referred to as unconventional railway superstructure. The structure of railway superstructure is characterized by cross sleepers used in a modified shape or they are not part of it at all. Currently, thus conceived railway track is referred to as a slab track (hereinafter referred to as the "ST"), which requires flexibility of the railway superstructure for the system of the wheel/rail secured using elastic elements disposed between the rail and the sleeper and/or under the sleeper. In general, the structure of ST has been currently applied mainly to high-speed track and the tracks that have high operational load, where the cost of maintaining the track with the classic structure of the railway superstructure strongly grows. At the same time, however, this structure also promotes in the upgraded sections of the standard tracks (track speed to 160 km.h-1), especially in track sections conducted in tunnels, as there are located the required properties of the ballast that do not demonstrate subsidence. The subgrade without a drop also offers for application of the ST structure bridges, and therefore, the application of this structure is also possible in these track sections.

Research on Traffic Safety of Freeway Upgrade Section

In this paper, upgrade section was classified based on linear combination form and whether or not constructing the climbing lane. Traffic accident characteristics on the upgrade section were analyzed from the viewpoint of vehicle type, accident type and time distribution. For in-depth study of accident causes, the paper analyzed traffic flow operation characteristics and discussed main influencing factors of traffic flow situation. In addition, the influence zone of upgrade section was put forward and defined. This laid good foundation for follow-up study on influence mechanism between microscopic traffic flow operation characteristics and traffic safety. Finally, the corresponding safety improvement measures were proposed.

Evaluation of Driver Perception–Reaction Time under Rainy or Wet Roadway Conditions at Onset of Yellow Indication

The research presented in this paper characterizes the impact of a wet pavement surface and rainy weather conditions on driver perception–reaction time (PRT) at the onset of the yellow indication on the approach to a high-speed signalized intersection. An in-vehicle differential Global Positioning System was used in a controlled field environment. Three hundred eighty-four data records for all drivers who stopped at the onset of the yellow indication were available for analysis. The minimum time to intersection (TTI) ranged from 2.35 s to 5.71 s. Statistical analyses were used to quantify the effects of the TTI, grade (uphill or downhill), gender, and age (<40 years, 40 to 59 years, and ≥60 years) on driver PRT. The study demonstrated that driver PRT increases as TTI increases. A longer PRT was found when vehicles traveled along an upgrade section, given that the driver was typically accelerating when the yellow indication was initiated. No gender differences were found in PRT, and no statistically significant differences were found between different age groups. Furthermore, the study demonstrated that driver PRT increased under conditions of a wet pavement surface and rainy weather as compared with clear weather conditions over the entire TTI range.

Short‐Term Impacts of a 4‐Lane Highway on American Black Bears in Eastern North Carolina

Short‐Term Impacts of a 4‐Lane Highway on American Black Bears in Eastern North Carolina

Jam Formation of Traffic Flow in Harbor Tunnel

This paper reports a study concerning occurrence and growth of traffic jam in a harbor tunnel. The single-lane with three sections (downgrade, flat, and upgrade) is taken into account and they are characterized with different velocity limit. At the low density, the traffic current increases linearly with density and saturates at some values of immediately density. As the density increases, the traffic jam appears firstly before the upgrade section and then extends to the downgrade section. Additionally, the relationships of the velocity and headway against position in different densities are obtained from simulation. These results clearly clarify where and when the traffic jam appears. Finally, the critical densities are derived via the theoretical analysis before and after the discontinuous fronts and the theoretical results are consistent with the critical values of simulation results.

New approach to determine number of lanes on freeway upgrades

A slow-moving heavy vehicle can substantially reduce traffic flow because the vehicle acts as a moving bottleneck. In particular, the bottleneck can be initiated on a long uphill freeway section where heavy trucks gain little acceleration and propagate upstream when the percentage of loaded trucks in the traffic is high. This paper finds an interesting relation between the bottlenecks and some physical factors including heavy vehicle characteristics, road geometry, traffic flow theory, and percentage of trucks in traffic. According to this relation, the paper provides two dimensionless physical parameters to characterize the formation and propagation of the queues initiated by loaded trucks on uniform upgrades, respectively. Based on the critical values of these parameters aforementioned, the paper can help transportation engineers to determine that the number of design lanes under the conditions that the growing bottlenecks initiate along upgrade section cannot be resolved by simply using equations and rules suggested in the 2000 edition of the Highway capacity manual.