Hasil untuk "Transportation engineering"

Predrag BRLEK, Javier GENÉ-MORALES, Francisco ALONSO et al.

Although cycling is widely renowned for its benefits to transport sustainability and individual health, the impact of cycling initiation age on cycling behaviours and safety outcomes remains underexplored in the scientific literature. The present study aimed to investigate the relationship between the age of initiation and self-reported cycling behaviours, safety skills and willingness to increase cycling participation. For this purpose, we used the data provided by 1,741 cyclists from five Balkan countries. Overall, no significant differences in onset ages were found between male and female riders. Regarding self-reported cycling behaviour, individuals who started cycling at an earlier age were less prone to unintentional risky behaviours and consistently reported better knowledge of traffic rules. Notably, earlier starters are those who currently engage in longer and more sustained cycling trips. However, they were also less likely to wear a helmet and more likely to engage with connected devices while cycling. This suggests that while the relationship between cycling onset ages and subsequent riding outcomes is relatively clear, it is neither tautological nor linear, highlighting the ongoing need for safety literacy initiatives. On a practical level, these findings underline the need for strategies that promote early cycling engagement while fostering sustained growth in active mobility and safer cycling practices.

Yingjun Jiang, Kejia Yuan, Jiangtao Fan et al.

Xiaojuan Sun, Haojie Jin, Mingyu Gao et al.

Abstract Reservoirs are essential for global water management and energy regulation, but sedimentation threatens their longevity. This study investigates a 130 km section of the Yellow River between the Sanmenxia and Xiaolangdi dams, using deep learning to predict long‐term erosion and deposition patterns. From 2009 to 2023, we gathered water depth data from 56 sites (840 measurements) with unmanned survey boats and drone‐based LiDAR (Light Detection and Ranging), alongside flow and sediment records. After preprocessing, we evaluated three machine learning models: Convolutional Network for Multimodal Time Series (CNN‐MTS), Convolutional Transformer for Multimodal Time Series (CNN‐Transformer‐MTS), and Convolutional Bi‐LSTM for Multimodal Time Series (CNN‐BiLSTM‐MTS). The CNN‐BiLSTM‐MTS model excelled, achieving a mean absolute error (MAE) of 17.84 m, a coefficient of determination (R2) of 0.9916, and reducing errors by up to 26% compared to alternatives. Key drivers of sediment dynamics included sediment load, maximum sediment concentration, and maximum flow. Data from 2009 to 2023 showed elevation shifts from −0.21 m near the dam to +1.158 m at the reservoir's tail. Predictions for 2024 to 2050 suggest varied riverbed changes, with the Guxian Reservoir's operation in 2036 expanding elevation ranges from −0.625 to 0.875 m. These findings highlight deep learning's potential for efficient sediment management in reservoirs and offer insights for sustainable hydraulic engineering. However, uncertainties persist in scaling the model, improving data resolution, and coordinating across regions.

Ibrahim Asi, Yusra I. Alhadidi, Taqwa I. Alhadidi

Italo Meloni, Giuseppe Musolino, Francesco Piras et al.

Lianxiang Zhang, Huanyu Wu, Xin Wang et al.

The continuous growth in building decoration activities has led to significant energy and material consumption, increasing carbon emissions in the construction sector. Existing literature frequently overlooks the carbon impact of building decorations. This study employs the life cycle assessment (LCA) method to quantify the carbon emissions associated with building decorations across five typic building types: residential, hospital, educational, sports cultural, and office buildings. Data were gathered using a mix of field investigations, document reviews, and semi-structured interviews, ensuring comprehensive coverage of all life cycle stages. The results reveal that carbon emission intensities of the studied building decorations ranged from 70.01 to 298.79 kg CO₂ eq/m², with the lowest emissions found in educational buildings and the highest in sports and cultural buildings. The decoration material production stage consistently emerges as the major contributor to emissions, accounting for over 50% of the life cycle of carbon emissions across all building types. The transportation stage also represents a significant share, contributing 18.6% to 24.5% across the building types. It also indicates that ceiling engineering as well as wall and column engineering are the primary carbon emission sources in terms of decoration activities. This study systematically compares the carbon emission characteristics of building decorations across multiple building types, addressing a gap that has been largely overlooked in the existing literature. It highlights the key sources of carbon emissions and proposes targeted mitigation strategies. The findings also suggest future research directions, including the application of innovative low-carbon materials, advanced construction technologies, and optimization of logistics. These insights lay a solid foundation for future low-carbon design and construction practices within the building sector.

Shunyao Wang, Ran Tu

Huang Susu, Zhang Miao, Zhao Yang

Omid Memarian Sorkhabi, Behnaz Shadmanfar, Mohammed M. Al-Amidi

Due to climate change, it is important to study the relationship between floods and sea-level rise in coastal city resilience. In this research sea surface temperature (SST) from MODIS, wind speed, precipitation, and sea-level rise from satellite altimetry are investigated for dynamic sea-level variability. An annual SST increase of 0.1C° is observed around the Gothenburg coast. Also in the middle of the North Sea, an annual increase of about 0.2C° is evident. The annual sea surface height (SSH) trend is 3 mm on the Gothenburg coast. We have a strong positive spatial correlation between SST and SSH near the Gothenburg coast. In the next step, dynamic sea-level variability is predicted with a convolution neural network and long short term memory. Root mean square error of wind speed, precipitation, SST, and mean sea-level forecasts are ±0.84 m/s, ±48.75 mm, ±3.48C° and ±24 mm, respectively. The 5-year trends of mean seal level show a significant increase from 28 mm/year to 46 mm/year in the last 5 year periods and the rate of increase has doubled. In the final step, the water rise of 5–10 m in Gothenburg city was simulated, and in the worst scenario, more than 50 % of the city will be damaged.

Bustanul Arifin, Bhakti Yudho Suprapto, Sri Arttini Dwi Prasetyowati et al.

The steering system in autonomous vehicles is an essential issue that must be addressed. Appropriate control will result in a smooth and risk-free steering system. Compared to other types of controls, type-2 fuzzy logic control has the advantage of dealing with uncertain inputs, which are common in autonomous vehicles. This paper proposes a novel method for the steering control of autonomous vehicles based on type-2 fuzzy logic control combined with PI control. The primary control, type-2 fuzzy logic control, has three inputs—distance, navigation, and speed. The fuzzy system’s output is the steering angle value. This was used as input for the secondary control, PI control. This control is in charge of adjusting the motor’s position as a manifestation of the steering angle. The study results applied to the EPS system of autonomous vehicles revealed that type-2 fuzzy logic control and PI control produced better and smoother control than type-1 fuzzy logic control and PI. The slightest disturbance in the type-1 fuzzy logic control showed a significant change in steering, while this did not occur in the type-2 fuzzy logic control. The results indicate that type-2 fuzzy logic control and PI control could be used for autonomous vehicles by maintaining the comfort and safety of the users.

Byung-Sik Ohm, Dong-Hyuk Jung, Su-Hyung Lee et al.

The objective of this study is to provide a process that can be applied in preparation for the introduction of an efficient and systematic pavement management system. This process includes features for selecting pavement segmentation (for management) and priority based on a cumulative difference approach(CDA), starting from the development of an index that reflects the pavement condition and current distribution status. For the index, which can reflect the current pavement conditions of sections to be managed, this study proposes a basic model form and establishes a simple modeling plan that uses only 3 points (maximum value, minimum value, and management standard) for typical flaws. For pavement segmentation, this study establishes a plan that uses a moving average combined with a minimum maintenance length standard to reflect existing condition distribution characteristics as much as possible. Finally, for priority, this study establishes a plan that performs selections using the averages of the index values of the sections that require maintenance, as determined via the segmentation step.

Guo-sheng Zhang, Xiao-yan Shen, Jun Hua et al.

For improving the emergency capacities during road transportation accidents of dangerous goods, this paper divides the accident emergency procedure into four subsystems: accident information processing, personnel rescue and evacuation, vehicle evacuation, and rescue materials delivery. On this basis, the causal mechanism and the loop diagrams of the emergency process are established by using the System Dynamics Method and Vensim software. First, six factors including transportation distance, the degree of mechanical modernization, delay time of personnel control, delay time of traffic information release, command level coefficient, and delay time of department arrival are selected as parameters to test the model’s sensitivity analysis. Then, the influences of the abovementioned factors on the observed value, such as the demand gap of on-site materials, number of people in safe area, number of vehicles in safe area, amount of disposal information, and the dynamic evolution behavior of the system, are analyzed. The results show that the transportation distance is shortened by half, and the time to fill the demand gap is reduced by 39%. The level of mechanical modernization is doubled, the peak inventory of materials in transit will increase by 9.2%, and the time to reach the peak will be shortened by 6.8%. If the delay time of personnel control is shortened by 480 s, the number of people to be evacuated in accident area will be reduced by 56. The delay time of traffic information release is shortened by 480 s, the number of vehicles to be evacuated is reduced by 74, and the time when the vehicle stops entering accident area is 1646 s in advance. The command level coefficient increases by 9.5%, and the speed of action execution increases by 9.6%.

Govind R. Gopal, Bhaskar D. Rao, Gabriel Porto Villardi

We address the problem of access point (AP) placement in small-cell networks with partial infrastructure flexibility, i.e., a novel class of problem in Beyond 5G, resultant from the utilization of unmanned aerial vehicles (UAVs) with AP functionalities (UAV-APs), to aid fixed wireless networks in coping with momentary peak-capacity requirements. We use the signal-to-generated-interference-plus-noise ratio (SGINR) metric as an alternative to the traditional signal-to-interference-plus-noise ratio (SINR) to quantify the effects of inter-cell interference (ICI) on the per-user capacity. From average SGINR, we derive the ICI-aware distortion measure leading to the Inter-AP Lloyd algorithm to obtain throughput-optimal AP placement for a fully flexible infrastructure. We then impose a hybridity constraint to the AP placement problem which turns a fraction of the network into a fixed infrastructure composed of terrestrial APs (T-APs) while the remainder is constituted by UAV-APs with flexibility in position. This newly formulated AP placement problem is solved by the proposed Lloyd-type algorithm called Hybrid AP Placement Algorithm (HAPPA). Furthermore, we present an initialization method for the Lloyd and Lloyd-type algorithms for Gaussian mixture models (GMMs) that offers an AP allocation leading to a higher rate compared to the k-means++ initialization. Finally, computer simulations show that the Inter-AP Lloyd algorithm can improve the performance of the worst users by up to 42.75% in achievable rate, assuming a fully flexible network. By using HAPPA on hybrid networks, we achieve improvements of up to 71.92% in sum rate over the fixed network and close the performance gap with fully flexible networks down to 2.02%, when an equal number of UAV-APs and T-APs is used. Further, our proposed initialization scheme always results in a balanced AP allocation, which means a more even distribution of users per AP, whereas the k-means++ scheme results in unbalanced allocations at least 30% of the time, resulting in a worse minimum rate.

Amirarsalan Mehrara Molan, Mahdi Rezapour, Khaled Ksaibati

Jingtao Shi, Weiyu Fan, Tihong Wang et al.

This paper analyzes the influence of a surfactant warm mix additive on unmodified asphalt’s conventional performance, viscosity-temperature characteristics, surface energy, and spreading performance on aggregate surfaces. The effect of the additive on asphalt’s microstructure was explored by infrared (IR) spectral analysis. The results show the additive has little influence on the penetration, softening point, ductility, and viscosity-temperature characteristics of asphalt; this suggests that the additive does not work by lowering viscosity. The additive can reduce the zero-shear viscosity of asphalt, and adding too much can reduce antirutting performance. The additive also increases the asphalt’s surface energy and the asphalt-water contact angle, while the polar component of surface energy decreases. The additive improves the spreading performance of asphalt on aggregate surfaces and reduces the asphalt-aggregate contact angle; the lower the temperature, the greater the reduction. IR spectral analysis shows that the additive does not react with asphalt—only physical blending occurs. The addition of a surfactant warm mix additive to asphalt allows asphalt mixtures to be more easily mixed and compacted at lower temperatures, thereby saving energy.

Jian Sun, He Dong, Guoyang Qin et al.

Adverse weathers are well-known to impact the operation of transportation systems, including taxis. This paper utilizes taxi GPS waypoint data to investigate the quantitative impact of rainfall on taxi hailing and taxi operations to help improve service quality on rainy days. Through statistical analysis, the study proves that it is more difficult to hail taxis on rainy days, especially during morning peak hours. By modelling the difference value of factors for rainfall and nonrainfall conditions in a multivariate regression model and attaining the significance and elasticity of each factor, passenger demand, taxi supply, search time and velocity are proved to be the significant factors that lower the taxis’ level of service on rainy days. Among them, the number of passengers and taxis are two factors that have the greatest impact. It is also shown that there is no significant difference in the total taxi supply and passenger demand between rainfall and nonrainfall conditions, but a dramatic change in the spatial distribution is discovered. The results suggest that instead of simply providing more taxis on rainy days, optimally dispatching taxicabs to high demand regions can be a more effective solution.

Yuxiong Ji, Yujing Zheng, Jizhou Zhao et al.

This paper envisions a multimodal passenger-and-package sharing (PPS) network for urban logistics integrating metro, taxi, and truck. A hub-and-spoke structure is designed including hubs located at metro stations and service stores connected to the hubs. Packages are transported by metro on backbone links between the hubs and are carried by taxis or trucks between service stores and hubs, depending on the unit costs of these two modes and capacity constraint of the taxi. A mixed integer linear programming model for hub location problems—fusing the multiassignment p-hub median problem without capacity constraints and the capacitated multiassignment p-hub covering problem—is formulated to optimize the multimodal PPS network. The model is implemented based on the real-world data in Shanghai (China) under a series of scenarios to evaluate the network performance from two perspectives: the number of hubs and the proportion of taxi drivers who are willing to carry packages. The scenarios show that with increased number of hubs, the spatial distribution of hubs disperses from the city center to peripheral areas and more areas can be serviced by taxis. There is, however, a trade-off between the operation cost saved by taxis and the establishment cost of an extra hub. The analysis also presents that if the proportion of taxis willing to carry packages associates with the incentive payments to taxi drivers, an optimal value of incentives exists, by balancing the operation costs of taxis and trucks.

Marie-Eve Will, Yannick Cornet, Talat Munshi

The space “consumed” by various urban passenger transport modes varies greatly depending on the size and the speed of vehicles. Past studies have shown that public transport (PT) and non-motorized transport (NMT) can be up to 20 times more space-efficient compared to a typical car. This optimal use of space is of relevance in an urban context where space is often a constrained resource. Yet space used by vehicles is rarely assessed in the practice of transport planning. There exists no standard method for quantifying the use of space in complex urban settings. This study proposes an approach based on the space-time concept for quantifying and comparing the dynamic (on-road) and still (parking) space used by different transport modes for a specific road network. Transport planning scenarios developed in the Low-carbon Comprehensive Mobility Plan (LCMP) prepared for the city of Rajkot are used to demonstrate the method. The indicators show that significantly less space is used by transport in a scenario that promotes higher use of PT and NMT in comparison to a business-as-usual scenario based on traffic projections for private motorized vehicles. These results provide evidence that could contribute to alleviating chronic congestion expected from car- and motorcycle-based transport development only. Overall, this research describes an assessment framework for low-carbon transport development that would include spatial efficiency concerns.

C. Tyler Dick, Pasi Lautala, Bryan W. Schlake

Demand for graduates with rail transportation expertise remains strong in North America, particularly in engineering and technical fields. Over the past decade, various activities by the American Railway Engineering and Maintenance-of-way Association and rail-focused University Transportation Centers have slowly re-established a railway engineering academic community. Railway courses are now offered at two dozen universities in the United States (U.S.), and, for the first time in decades, several universities offer specific degrees in railway engineering. Despite this progress, challenges remain, such as raising student awareness of rail industry career paths. Since most railway engineering courses are senior-level electives, many students are already committed to other engineering disciplines before they are exposed to railway concepts. To raise student interest in rail courses and satisfy industry demands for internships, students must be introduced to railway concepts before they decide on the direction of their studies. One approach to directing more rail-aware students into engineering programs is rail-themed outreach to K-12 students. Railways still hold a fascination for many young people as complex, multidisciplinary systems, and numerous interesting science, technology, engineering, and math (STEM) concepts can be demonstrated through the lens of railway transportation. Interactive rail-themed classroom activities can illustrate STEM topics while highlighting rail career opportunities and reinforcing railway transportation. This paper reviews rail-themed K-12 STEM outreach activities being undertaken by universities and the strong partnerships between industry and academia required to grow future generations of railway professionals.

Caleb Ronald Munigety