Exploring the Effects of Urban Built Environment on Road Travel Speed Variability with a Spatial Panel Data Model

Road traffic congestion is a common problem in most large cities, and exploring the root causes is essential to alleviate traffic congestion. Travel behavior is closely related to the built environment, and affects road travel speed. This paper investigated the direct effect of built environment on the average travel speed of road traffic. Taxi trajectories were divided into 30 min time slot (48 time slots throughout the day) and matched to the road network to obtain the average travel speed of road segments. The Points of Interest (POIs) in the buffer zone on both sides of the road segment were used to calculate the built environment indicators corresponding to the road segment, and then a spatial panel data model was proposed to assess the influence of the built environment adjacent to the road segment on the average travel speed of the road segment. The results demonstrated that the bus stop density, healthcare service density, sports and leisure service density, and parking entrance and exit density are the key factors that positively affect the average road travel speed. The residential community density and business building density are the key factors that negatively affect the average travel speed. Built environments have spatial correlation and spatial heterogeneity in their influence on the average travel speed of road segments. Findings of this study may provide useful insights for understanding the correlation between road travel speed and built environment, which would have important implications for urban planning and governance, traffic demand forecasting and traffic system optimization.

Investigation of Motorcycle Trajectories in 2-lane Horizontal Curves

Most of the road design guidelines assume that the vehicles traverse a trajectory that coincides with the midline of the traffic lane. Based on this assumption the thresholds of various features are determined such as the maximum permissible side friction factor. It is therefore important to investigate the extent to which the trajectory of the vehicles is similar to the horizontal alignment of the road or substantial differences exist. To this end, a naturalistic riding study was designed and executed with the use of an instrumented motorcycle which measured the position of the motorcycle with great accuracy in a rural 2-lane road segment. The derived trajectories were then plotted against the horizontal alignment of the road and compared with the 3 consecutive elements which form a typical horizontal curve i.e., the entering spiral curve, the circular curve, and the exiting spiral curve. Linear equations were developed which correlate the traveled curvatures with the distance of each horizontal curve along the road segment under investigation. The process of the data revealed that the riders differ their trajectory compared to the alignment of the road. However, in small radius horizontal curves is more likely to observe curvatures that are similar to the geometric one. Moreover, the riders perform more abrupt maneuvres in the first part of the horizontal curves while they straighten the handlebars of the motorcycle before the end of the curve. The present paper aims to shed light on the behavior of motorcycle riders on horizontal curves and hence to contribute to the reduction of motorcycle accidents, particularly the single-vehicle ones.

PLANNING EVALUATION OF RIGID PAVEMENT’S THICKNESS ON INTERSECTION OF A ROAD SEGMENT OF SIKUI KM. 34 NATIONAL ROAD STA. 0+000 S/D 0+300 EAST BARITO DISTRICT

East Barito is one district that has a variety of natural resources such as agriculture and mining, Sikui KM of National Highway 34 is one of the roads that used to be accessed by one party mobilization of existing mines in Central Kalimantan. But on the other hand, the national road Sikui KM 34 is also used for connecting roads between provinces or cities. Based on the above actual national roads not intended for large-laden vehicles.Path planning is aimed to obtain a rigid pavement thickness based on the Pavement Design Manual Nomor 02/M/BM/2017 which controlled by “Pedoman Perencanaan Perkerasan Jalan Beton Semen Pd T-14-2003” and calculating the budget plan on the intersection of a road segment of Sikui KM 34 national road, East Barito disctrict.On the planning of rigid pavement’s thickness by using “Manual Desain Perkerasan Jalan Nomor 02/M/BM/2017” it is found that the concrete plate layer = 28,5 cm; LMC base layer = 10 cm; drainage layer = 15 cm and by using “Pedoman Perencanaan Perkerasan Jalan Beton Semen Pd T-14-2003” also found that the concrete plate layer = 21 cm; base layer = 15 cm. After that, on the existing condition obtained concrete plate layer = 30 cm; K-125 concrete layer = 10 cm. Then, it is found that the efficient pavement’s thickness which taken by using “Pedoman Perencanaan Perkerasan Jalan Beton Semen Pd T-14-2003” is more efficient rather than the existing condition. Moreover, this thesis also discusses the budget plan on the intersection of a road segment of Sikui Km. 34, East Barito district.

Effects of Fog in a Brazilian Road Segment Analyzed by a Driving Simulator for Sustainable Transport: Drivers’ Speed Profile under In-Vehicle Warning Systems

Intelligent transport systems enable vehicles to communicate with each other and with the environment, ensuring road safety. Their implementation can help reduce the number of accidents, especially in stretches of s-curves, where speed control is essential to ensure the safety of drivers, and under hazardous weather conditions. Such systems promptly notify drivers about potentially dangerous road conditions, such as fog, so that they can better adapt their driving behavior. This study evaluates the driver’s speed profile in different scenarios (clear weather, fog weather, and fog with an in-vehicle fog warning system) considering the road geometry elements (s-curves). A driving simulator recreated the real scenarios of a principal Brazilian road segment, showing the geometric and weather conditions of a road known for its several s-curves and frequent incidence of fog. A preliminary study identified the most critical curves through a weighted severity index methodology to define the critical segment. The results showed drivers considerably reduced their speed in the scenario with a warning system, thus contributing to the safety of s-curved segments. The implementation of in-vehicle warning systems can avoid or reduce the need for major infrastructure interventions such as geometric design, through investments in new intelligent transport systems.

Appraising Pavement Surface Distresses And Expected Mitigation Measure On Selected Road Segment

The work visually inspects and evaluate the pavement failures and their causes as well as resolution methods. It is quite important to examine and identify the causes of the failed pavement to select a proper treatment option. The study consisted of two tasks: the first covers the detail visual inspection of the existing pavement failures, whereas the second investigates the actual causes of these failures. From Areka to Wolaita Sodo was selected for investigation. An intensive field work was carried out on the existing pavement condition of this road. It was found that most of the damaged pavement sections suffered from severe cracking, potholes and raveling failures. These failures might have been caused by fatigue failures on pavement structure due to the movement of heavily loaded truck – trailers. The damage could also be attributed to poor drainage, inadequate design and improper pavement materials.

Effects of Fog in a Brazilian Road Segment Analyzed by a Driving Simulator for Sustainable Transport: Drivers’ Visual Profile

Visibility is a critical factor for drivers to perceive roadway information, and fog is an inclement weather condition that directly impacts their vision, since it reduces both overall contrast and visibility of the driving scene. Visual attention has been considered a contributing factor to traffic crashes, and fog-related accidents are prone to be more severe and involve multiple vehicles. The literature lacks studies on the influence of fog on drivers’ visual performance and environment’s infrastructure design. This article investigates the effects of fog on drivers’ performance in a Brazilian curved road segment through a driving simulator experiment – more precisely, whether the presence of fog (foggy scenario) or its absence (clear scenario) significantly affects the visual profile. In the foggy scenario, the results showed the tracked area was concentrated in a smaller region, despite an increase in the number of fixations compared with the clear scenario. The fixation duration did not change between the scenarios and the pupil dilation was shorter in the foggy one. The study shows the influence of environmental conditions on the driver’s performance and is one of the first on the use of driving simulators with realistic representations of the road infrastructure and its surrounding for the understanding of driving under fog in the Brazilian scenario. Besides roadway geometry elements, driving simulator studies enable analyses of features related to the interaction between route environment and driver’s answer, and can improve safety in places with visibility problems caused by fog, reducing their environmental impact and preserving drivers’ lives.

Vertical Electrical Sounding (VES) investigation for road failure along Mekelle – Abi-Adi road segment, northern Ethiopia

Roads constructed along the mountainous terrains of Ethiopia are susceptible to landslides mostly during rainy season. Mekelle – Abi Adi road is one of the economically important road corridors that connects many towns with Mekelle city. However, the asphalt road segment is heavily affected by quasi-translational type of landslide which hinders traffic flow of the area. Vertical electrical sounding (VES) method was applied to investigate subsurface geology of the road failure along Mekelle – Abi-Adi asphalt road, northern Ethiopia. The geo-electric section result revealed that the shallow subsurface geology of the site is characterized by four distinct geological formations, from top to bottom are: shale, shale-limestone intercalation, limestone and shale-gypsum units. The subgrade of the failed road section is shale unit which is overlain by jointed sandstone unit. The sandstone unit serves as a recharge zone to the bottom shale layer by percolating water via sub-base fill materials which in turn blocks vertical percolation and promote seepage force to the overlying soil mass. Hence, the road failure in the study area seems to be caused due to the development of pore water pressure in the shale layer which soaked water during heavy rainfall. The recommended remedial method for the road failure is re-designing of the affected route from chainage 48 km+850 m to 49 km+250 m towards the northwest of the study area and excavates the top 6 m shale unit.

Intersection-Based Routing with Fuzzy Multi-Factor Decision for VANETs

Due to the limitations of the urban environment, the data transferred between vehicles can only change direction at the intersections. Therefore, the routing decision at an intersection will largely affect the overall routing decision. In this article, we propose an Intersection-Based Routing with Fuzzy Multi-Factor Decision (IRFMF), which utilizes several factors to decide the next road segment. In the scheme, each intersection introduces three factors including the direction, the number of lanes, and the traffic. After the fuzzification and defuzzification of these factors, the candidate segment with the highest evaluation will be selected. The simulation shows a significant improvement of VANETs performance on packet delivery ratio and end-to-end delay.