Dual Carriageway Research Articles

Sound Radiation from Vehicles on the Right-Angle Bend of the Road

Sound radiation from vehicles traveling on a city road with a right-angle bend is studied. The effect of wind on the acoustic field is taken into account. First, a solution to the problem for two-point noise sources moving in opposite directions is found using the integral Fourier transforms over space variables and time. Inverse transforms are calculated approximately using the stationary phase method. A solution to the general problem is obtained as a superposition of many partial solutions. The numerical analysis of traffic noise characteristics is carried out for the case of a dual carriageway Textile Workers Avenue in the town of Łodź, Poland.

An Approach for Development of Local Safety Performance Functions for Multi-Lane Rural Divided Highways in Egypt

Egypt is a middle-income country, belonging to the Eastern Mediterranean Region (EMR). Egypt used to be the worst performing EMR country, with over 45 fatalities per 100,000 population. It is considered an example case of many EMR countries in the region where there is a need for quantitative assessment of safety on its roads. The Highway Safety Manual (HSM) offers several functions to calculate safety performance (SPFs), which can estimate crash frequency on a highway network according to its geometric and traffic characteristics. The HSM was developed in the United States using road and crash data specific to its environment. Jurisdictions and other non-U.S. regions were encouraged to develop locally derived models suitable for the local characteristics of roads and crashes. The objective of this paper is to assess the suitability of using the HSM models on rural multi-lane divided highways in Egypt. The calibrated SPFs considering Egyptian road factors were compared with the actual crash events. The results showed that there was a need to develop locally derived SFPs using negative binomial models. The modeling approach and a validation procedure were presented and are applicable when developing local SPFs to compare how well the model performs to the actual data, and to HSM calibrated models. The models were created using 90% of the data and tested on the remaining 10% of the data. The study found that the results relating to driver behavior would help designers in regions other than the United States to benefit from the HSM.

Control of settlement and volume loss induced by tunneling under recently reclaimed land

The proposed Tuen Mun–Chek Lap Kok Link (TM-CLKL) project comprises a 9-km-long dual two-lane carriageway between Tuen Mun and North Lantau, Hong Kong. Construction of the two tunnels at the Northern Landfall Fall was carried out by two TBMs: the northbound is referred to as ML03 and has an excavated diameter of 17.63 m, and the southbound is referred to as ML02 and has an excavated diameter of 14.00 m. The use of TBMs minimized the amount of dredging and removal of soft marine deposits, resulting in less impact to the environment within and near the work site of the project. Ground treatment in the form of deep vibro-compaction was carried out at the sand fill and band drains installed in the marine deposit. A surcharge was also added above the final formation level to limit the residual settlement and differential settlement of the reclaimed land to less than 500 mm and 1 in 300, respectively, for a design life of 50 years. Finite element analyses were performed to predict the settlement trough under different confinement pressures along the tunnel alignment. Extensive monitoring of the ground movement was carried out during the driving of the two TBMs to ensure that the design confinement pressure of the slurry would not cause excessive settlement, heave, or blow out at the shallow tunnel sections or different facilities along the tunnel alignment. The monitoring data was then used to back-calculate the percentage of volume loss, which is a key index describing the behavior of the ground during excavation. The monitoring data showed that the measured settlement and back-calculated volume loss were much lower than the predicted values.

Traffic Control Devices for Deterring Wrong-Way Movements at Unsignalized Intersections on Divided Highways

Motorists driving the wrong way on divided roadways has been an area of concern for over 50 years. However, little is known about the nature of wrong-way crashes on divided highways. Thus, the research team conducted exploratory and statistical analyses to assess the effects of median width and select traffic control devices upon wrong-way crashes on high-speed divided highways. The exploratory analysis revealed that most of the wrong-way crashes on high-speed divided highways resulted in serious injury and happened at night. More than two-thirds of the wrong-way crashes resulted from a wrong-way maneuver at an intersecting roadway where a median opening was present. The statistical analysis found numerous sites where the traffic control in the median opening did not fully comply with the Manual on Uniform Traffic Control Devices (MUTCD) with respect to treating the location as one or two intersections. There was also evidence from the statistical analysis that the 30-ft median width threshold may not be appropriate for distinguishing between one or two intersections. In addition, researchers were able to identify several traffic control devices that may be effective in reducing wrong-way movements on high-speed divided highways. The final effort of the project was to develop recommended MUTCD language for implementing the research findings. The recommended language includes a new method for distinguishing between divided highway crossings that function as a single intersection or two separate intersections, thereby eliminating the 30-ft median width threshold used in the current MUTCD.

Traffic Assessment for Completion of Road Upgrading from Secondary Road to Dual Carriageway

A traffic study was carried out at the signalized intersections to assess the road condition after a road upgrading from secondary road (3 m wide lane) to dual carriageway (3.5 m wide lane). The site selected was Tudan Road, which is located in Miri City in Sarawak State, Malaysia, and it is about 20-minute drive from the Border of Brunei Darussalam. Tudan Road connects Kuala Baram Bypass and Lutong-Kuala Baram Road with traffic light intersections. Traffic count data was collected at both intersections of Kuala Baram Bypass and Lutong-Kuala Baram Road by recording the traffic volume for every 15 minutes interval during an hour period of morning and afternoon peak hours. The collected data were then analysed according to Highway Capacity Manual (HCM) 2010 to determine Level of Service (LOS). By using the traffic volume collected, the LOS was estimated for Tudan Road as a secondary road prior to upgrading. The results indicated that the LOS during weekend afternoon has improved from Level F to B for Lutong-Kuala Baram Road intersection and Level F to D for Kuala Baram Bypass intersection after the upgrading of Tudan Road to dual carriageway. During weekday afternoon, the LOS for both intersections has also improved. The LOS for both intersections varied between morning and afternoon, and between weekday and weekend. The variation is caused by changes in lane capacity and volume-to-capacity ratio for different periods when the road users might actively commute for daily work or some leisure activities. Intersection delay time reduced 50% at Lutong-Kuala Baram Road and 74% at Kuala Baram Bypass after the road upgrading. From the LOS analysis, it proved that the upgrading of Tudan road has improved intersection performance at Lutong-Kuala Baram Road and Kuala Baram Bypass with different levels depending on morning or afternoon, and weekday or weekend.

Random parameter probit models to analyze pedestrian red-light violations and injury severity in pedestrian–motor vehicle crashes at signalized crossings

Pedestrian red-light violations at signalized crossings are an important traffic safety concern, particularly in densely populated cities. In this study, the authors quantitatively investigated the factors associated with pedestrian red-light violations and injury severity resulting from pedestrian–motor vehicle crashes at signalized crossings. Random parameter probit models are used to account for individual-specific heterogeneity that arises from a set of unmeasured factors related to traffic conditions and the pedestrians’ physical and mental status. Data for the analysis are based on the historical crash record maintained by the Hong Kong Transport Department. Children younger than age 11 years are not only associated with a higher likelihood of pedestrian red-light violations but also tend to have a higher probability of severe injuries. Factors including summer, dual carriageways with a central traffic island, and pedestrian age of 12 to 25 years are solely related to a higher likelihood of pedestrian red-light violations; meanwhile, variables solely associated with a higher probability of severe injuries include crashes that occur between 22:00 and 06:59, crashes occurring in rainy weather, crashes involving pedestrians older than age 46 years, and bus crashes. Appropriate countermeasures are recommended to curb pedestrian red-light violations and to reduce the injury severity of pedestrian crashes.

Overview of intermediate highway cross-sections

The paper presents an overview of safety and insights regarding traffic at highway intermediate cross-sections in the interurban highway network. This overview includes rigid and soft ‘one plus one’ cross-sections, passing lanes traffic and geometric characteristics, as well as criteria for widening a two-lane highway to form a divided multilane highway. The design overview of intermediate highway cross-sections includes traffic and safety warrants, design speed characteristics and cross-section infrastructure components, including elements that enhance traffic safety. These developments are partly an outcome of the new Israeli geometric design policy and controls for rural (interurban) highways.

ANN based short-term traffic flow forecasting in undivided two lane highway

Short term traffic forecasting is one of the important fields of study in the transportation domain. Short term traffic forecasting is very useful to develop a more advanced transportation system to control traffic signals and avoid congestions. Several studies have made efforts for short term traffic flow forecasting for divided and undivided highways across the world. However, all these studies relied on the dataset which are greatly varied between countries due to the technology used for transportation data collection. India is a developing country in which efforts are being done to improve the transportation system to avoid congestion and travel time. Two-lane undivided highways with mixed traffic constitute a large portion of Indian road network. This study is an attempt to develop a short term traffic forecasting model using back propagation artificial neural network for two lane undivided highway with mixed traffic conditions in India. The results were compared with random forest, support vector machine, k-nearest neighbor classifier, regression tree and multiple regression models. It was found that back-propagation neural network performs better than other approaches and achieved an R2 value 0.9962, which is a good score.

Traffic Safety at Median Ditches: Steel vs. Concrete Barrier Performance Comparison Using Computer Simulation

In Turkey, concrete V-shaped ditches are formed at the median section of divided highways to provide drainage. Recent accidents show that these ditches actually present safety risks to vehicles entering the medians. Vehicles either cross over the ditch, roll over, or become trapped in the ditch, depending upon the mass, size, speed, and angle of the entering vehicle. To overcome this safety risk and reduce the severity of these accidents, longitudinal barriers are installed along these ditches. Currently, in Turkey, steel barriers are extensively used to improve traffic safety at median ditches. In this paper, the crash performances of steel and concrete barriers used at medians with ditches are compared. A model of a standard steel EDSP-1.33 barrier and a model of a newly developed concrete C470 barrier were constructed, and impact simulations were performed for when they are installed at a ditch slope break point. A nonlinear finite element program, LS-DYNA, was used for the analysis. A 13,000 kg bus model was used to impact both barriers in accordance with European standard requirements for crash tests. Simulation results show that when the steel EDSP-1.33 barrier is used, the bus has the potential for excessive penetration of the ditch, with significant barrier deformation. Moreover, the barrier damage is extensive, resulting in increased maintenance costs. On the other hand, the concrete C470 barrier successfully contains and redirects the 13,000 kg bus impact, with minimal barrier deformation and safety risk. Even though the concrete barrier slides toward the inside of the ditch, the bus does not enter the ditch area and exits the barrier in a stable manner. Therefore, to increase traffic safety at ditches located at the median section of divided highways in Turkey, utilization of the newly developed concrete barrier C470 is recommended.

On the rules of continuity and symmetry for the data quality of street networks.

Knowledge or rule-based approaches are needed for quality assessment and assurance in professional or crowdsourced geographic data. Nevertheless, many types of geographic knowledge are statistical in nature and are therefore difficult to derive rules that are meaningful for this purpose. The rules of continuity and symmetry considered in this paper can be thought of as two concrete forms of the first law of geography, which may be used to formulate quality measures at the individual level without referring to ground truth. It is not clear, however, how much the rules can be faithful. Hence, the main objective is to test if the rules are consistent with street network data over the world. Specifically, for the rule of continuity we identify natural streets that connect smoothly in a network, and measure the spatial order of information (e.g. names, highway level, speed, etc.) along the streets. The measure is based on spatial auto-correlation indicators adapted for one dimension. For the rule of symmetry, we device an algorithm that recognize parallel road pairs (e.g. dual carriageways), and examine to what extent attributes in the pairs are identical. The two rules are tested against 28 cities selected from OpenStreetMap data worldwide; two professional data sets are used to show more insights. We found that the rules are consistent with street networks from a wide range of cities of different characteristics, and also noted cases with varying degrees of agreement. As a side-effect, we discussed possible limitations of the autocorrelation indicators used, where cautions are needed when interpreting the results. In addition, we present techniques that performed the tests automatically, which can be applied to new data to further verify (or falsify) our findings, or extended as quality assurance tools to detect data items that do not satisfy the rules and to suggest possible corrections according to the rules.

The influence of periglacial action on road construction: a case study from the A21 Tonbridge to Pembury dualling

Periglacial processes have resulted in the formation of features including relict shear surfaces on failed slopes and gulls where valley cambering has occurred. This paper presents field observations of periglacial features encountered during construction of a dual carriageway between Tonbridge and Pembury in Kent. Methods to manage the risks presented by the features are included and the difficulty of identifying gull features is also discussed.

The association between exposure to environmental factors and the occurrence of attention-deficit/hyperactivity disorder (ADHD). A population-based retrospective cohort study

BackgroundA number of factors contribute to attention deficit hyperactivity disorder (ADHD) and although they are not fully known, the occurrence of ADHD seems to be a consequence of an interaction between multiple genetic and environmental factors. However, apart from pesticides, the evidence is inadequate and inconsistent as it differs not only in the population and time period analysed, but also in the type of study, the control of the confounding variables and the statistical methods used. In the latter case, the studies also differ in the adjustment of spatial and temporal variability. Our objective here, is to provide evidence on an association between environmental factors and ADHD. MethodsIn our study, we used a population-based retrospective cohort in which we matched cases and controls (children free of the disease) by sex and year of birth (n = 5193, 78.9% boys). The cases were children born between 1998 and 2012 and diagnosed with ADHD (n = 116).To evaluate whether there was a geographical pattern in the incidence of ADHD, we first represented the smoothed standardized incidence rates on a map of the region being studied. We then estimated the probability of being a case by using a generalized liner mixed model with a binomial link. As explanatory variables of interest, we included the following environmental variables: distance to agricultural areas, distance to roads (stratified into three categories according to traffic density and intensity), distance to petrol stations, distance to industrial estates, and land use. We control for both observed (individual and family specific variables and deprivation index) and unobserved confounders (in particular, individual and familial heterogeneity). In addition, we adjusted for spatial extra variability. ResultsWe found a north-south pattern containing two clusters (one in the centre of the study region and another in the south) in relation to the risk of developing ADHD. The results from the multivariate model suggest that these clusters could be related to some of the environmental variables. Specifically, living within 100 m from an agricultural area or a residential street and/or living fewer than 300 m from a motorway, dual carriageway or one of the industrial estates analysed was associated (statistically significant) with an increased risk of ADHD. ConclusionOur results indicate that some environmental factors could be associated with ADHD occurring, particularly those associated with exposure to pesticides, organochlorine compounds and air pollutants because of traffic.

Effects of higher maximum speed limits to vehicle speeds: A before - after analysis on rural divided highways in Vietnam

This study is to assess the effects of raising speed limits to vehicle operating speeds on rural divided highways in Vietnam. Vehicle speeds were recorded at three different sites of three routes during the daytime and nighttime, both before and after speed limits on these sites increasing from 80 km/h to 90 km/h. The results have shown that the percentage of speeds exceeding speed limits had a wide range from 0% to nearly 30% with regard to different locations, survey time and speed limits. The extent of speeding in some cases was very high even after speed limit increased. It was found that in most cases, the changes in mean speeds after a higher speed limit was applied were statistically significant at the p-value of 0.05, however, the magnitudes of the mean change varied considerably between locations and survey times. Because four out of six cases under the study having mean speeds increased by over 10 km/h after setting up a higher speed limit, this study suggests that further appropriate measures of speed control and speed management should be applied along with increasing speed limit to ensure traffic safety on rural divided highways in Vietnam.
 Article history: Received 27 March 2018, Revised 18 April 2018, Accepted 27 April 2018

Speed prediction models for car and sports utility vehicle at locations along four-lane median divided horizontal curves

Sites with varying geometric features were analyzed to develop the 85th percentile speed prediction models for car and sports utility vehicle (SUV) at 50 m prior to the point of curvature (PC), PC, midpoint of a curve (MC), point of tangent (PT) and 50 m beyond PT on four-lane median divided rural highways. The car and SUV speed data were combined in the analysis as they were found to be normally distributed and not significantly different. Independent parameters representing geometric features and speed at the preceding section were logically selected in stepwise regression analyses to develop the models. Speeds at various locations were found to be dependent on some combinations of curve length, curvature and speed in the immediately preceding section of the highway. Curve length had a significant effect on the speed at locations 50 m prior to PC, PC and MC. The effect of curvature on speed was observed only at MC. The curve geometry did not have a significant effect on speed from PT onwards. The speed at 50 m prior to PC and curvature is the most significant parameter that affects the speed at PC and MC, respectively. Before entering a horizontal curve, drivers possibly perceive the curve based on its length. Longer curve encourages drivers to maintain higher speed in the preceding tangent section. Further, drivers start experiencing the effect of curvature only after entering the curve and adjust speed accordingly. Practitioners can use these findings in designing consistent horizontal curve for vehicle speed harmony.

Traffic condition with road upgrading during construction and operation stages based on level-of-service (LOS)

In this study, traffic survey was done at signalized intersection of both ends of an upgrading road during morning and afternoon peak hours throughout construction period. The intersections of Tudan Road located at Miri City in Sarawak State, Malaysia were chosen as study sites. The aim of this research was to investigate the traffic condition for the signalized intersections of a R3 secondary road that being upgrading to standard U5 dual carriageway during peak hours for construction and operation stages. Data collected from these sites were analyzed according to Highway Capacity Manual (HCM) 2010. From the results, the level-of-services (LOS) of Kuala Baram By Pass Road intersection improved from Level F to Level E at operation stage for weekday during peak hours in the morning. LOS of Lutong-Kuala Baram Road intersection at construction stage were Level C during peak hours in the morning and Level D during peak hours in the afternoon for weekends. However, the LOS during both peak hours for weekends were projected to improve to Level B at the operation stage. It proved that the road construction has affected LOS, and this temporary issue can be solved after the upgraded road is in operation.

Yachihe Bridge, China: engineering the world’s longest cable-stayed steel truss

Yachihe Bridge in China is the longest steel-truss, cable-stayed bridge in the world and the tenth longest overall. Completed in 2016, its 800 m main span carries the new Guiyang–Qianxi dual carriageway over the Yachihe River gorge. It is also the first cable-stayed bridge to be erected using a cable crane, and its concrete-box-girder side spans feature the first use of cable anchorages in the middle of the outer web. Furthermore, geometry alignment during deck closure was achieved by adjusting cable forces rather than by using counterweights. This paper describes the configuration and numerical analysis of the innovative cable anchorage, discusses the challenges and solutions involved in using a cable crane for construction and details the novel closure techniques adopted for the steel-truss deck.

TBM tunnelling under the Suez Canal – Port Said tunnels in challenging ground conditions

AbstractThe Port Said Tunnels Project consists of twin road tunnels crossing the Suez Canal with a planned capacity of 2,100 mixed vehicles/hour in each direction. The dual carriageway tunnels are an important part of the Suez Canal Region Development Plan, which will connect the Sinai with other Egyptian provinces to provide a gateway for investment opportunities and speed up the development of Sinai province. The project is located 19 km south of Port Said city, near the northern entrance of the Suez Canal. The tunnels are constructed using slurry shield TBMs in difficult ground conditions, including the presence of methane gas. This paper demonstrates the main challenges encountered during tunnelling and the measures taken to mitigate potential risks during construction and to control long‐term differential settlements in the upper, very soft soil. The tunnels are connected by two cross passages which are being constructed using ground freezing and conventional tunnelling.

Simulation of Traffic Flow to Analyze Lane Changes on Multi-lane Highways under Non-lane Discipline

The present study uses the microscopic traffic simulation flow model VISSIM for generating traffic flow data to obtain the essential parameters. Study calibrated and validated the VISSIM model based on the field data. Further, lane change behaviour is analyzed with homogeneous vehicle type traffic on four-lane, six-lane and eight-lane divided highways sections through VISSIM simulation model. The study finds the number of lane changes depends on traffic volume as well as on a number of lanes provided for a direction of travel. Lane change data was correlated with traffic volume, and the third-degree polynomial trend was found to be fitted on each type of simulated highway sections. A maximum number of lane changes and lane change at the capacity level of the volume are also quantified on simulated sections of four-lane, six-lane and eight-lane divided highways.

Assessment of Dual Carriageway for Sustainable Socio-Economic Development in Ado Ekiti, Nigeria

Various studies have been carried out on urban dual-carriage ways and its implication on sustainable development in different parts of world. In Nigeria, work on dual carriageway for sustainable development still remained under explored. This study therefore, focused on urban dual carriageway for sustainable development of Ado- Ekiti and to enhance good quality of life of the people. Data for this study were obtained from primary and secondary sources as well as field observation.250 copies of questionnaire were administered in 5 purposively selected areas in Ado-Ekiti with the use of questionnaire. Simple random sampling method was used to choose 30 houses at an interval of 10 houses through balloting .Secondary data were sourced through journal articles and edited books. Data were analyzed using both descriptive and inferential statistic techniques. Chi-square statistical method were adopted to test the two hypotheses stated (i) effect of dual carriageway on socio-economic activities in the area and (ii) the impact of dual carriageway on travel time and cost of transport in the area at 5% level of significance. It was discovered that dual carriageway has great influence on socio - economic activities, trip generation, travel time, cost of transport among others in Ado- Ekiti

Modelling Assessment on Causes of Road Accidents Along Kilimanjaro-Arusha Highway in Tanzania

This paper aims on assessing the risk factors which are associated to the cause of road accidents in Kilimanjaro-Arusha highway 78.46km. Road accidents have been one of the paramount road cases in Tanzania. However, when ensuring road safety rules in Tanzania, it is important to assess the nature and causes of road accidents in the country. It is also necessary to find out the factors which lead to an obstacle of achieving road safety and regulations. This paper focuses on the assessment of road accidents in Tanzania and the associated factors such as inadequate road signs, inadequate carriageway width, lack of pedestrian facilities and law enforcement are considered to be critical shortcomings. The findings have shown the considerable proportions of accident and its outcomes of death and injuries at various black spot such as Kikavu River 60%, Kikatiti 20%, Nduruma bridge 10%, Kilala slope 5%, and Sadec 5%. Also missing and poor road makings and road signs from CH: 0+200 -22+600 needs to be rectified. In order to reduce road accidents in Kilimanjaro-Arusha section, the Government should rectify black spot areas by considering geometric standard in highway, set aside fund for provision and maintenance of traffic control devices, train road users on traffic laws and regulations, set aside fund for increasing road width with consideration of dual carriage way and climbing lane along mountain Kikavu area to reduce the action of overtaking. This study has revealed the pattern and trends of road accidents in Kilimanjaro-Arusha from 2013 to 2016. It shows that the accident occurrence was showing sign of decreasing from 2015 up to 2016. Passengers and pedestrians are the groups which identified to be always at highest risk of being injured or highly prone to motor traffic accidents. Driving under alcoholic behaviour (drugs, alcohol), distraction, over speed driving, overtaking, poor vehicle parking management and pedestrian fault are among of road user behaviour identified to cause accidents within the stretch.