This paper presents a new algorithm to build feasible solutions to a MILP formulation of the vertical alignment problem in road design. This MILP involves a large number of special ordered set of type 2 variables used...
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This paper presents a new algorithm to build feasible solutions to a MILP formulation of the vertical alignment problem in road design. This MILP involves a large number of special ordered set of type 2 variables used to describe piecewise linear functions. The principle of the algorithm is to successively solve LPs adapted from the MILP by replacing the special ordered set of type 2 constraints by linear constraints. Proof that the solutions to the successive linear relaxations of the MILP converge to a feasible solution to the MILP is provided. Numerical results emphasize that the algorithm performs better than CPLEX for large scale vertical alignment problems.
With the rapid promotion of autonomous driving technology, it is extremely important to scientifically anticipate the related technologies and analyze their possible impact on urban road systems. The accuracy of detec...
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With the rapid promotion of autonomous driving technology, it is extremely important to scientifically anticipate the related technologies and analyze their possible impact on urban road systems. The accuracy of detection and localization of traffic elements of autonomous driving is closely related to the ability of autonomous driving devices to make control decisions and the safety of autonomous driving. The study designs a new high-speed road driving scheme based on autonomous driving by analyzing the challenges related to urban traffic that may be brought about by unmanned driving. On the basis of the faster R-CNN algorithm, the context information around the target is introduced to locate and detect small-scale traffic signs. A new pedestrian detection model is designed, which is based on the feature pyramid network and introduces the SE module to highlight the features of the visible part of the pedestrian and reduce the missed detection rate caused by inter-class occlusion. The improved traffic sign detection framework improves the detection accuracy by 18.91% compared to the original faster R-CNN, while the enhanced pedestrian inspection method improves the detection accuracy by 14.00%. For both traffic sign detection and pedestrian detection accuracy and speed are improved compared to the original method.
City events take place in the Zhangzhou Olympic Sports Center, resulting in traffic. Hence, this study analyzed the road planning and design around Zhangzhou Olympic Sports Center through traffic demand forecasting. T...
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City events take place in the Zhangzhou Olympic Sports Center, resulting in traffic. Hence, this study analyzed the road planning and design around Zhangzhou Olympic Sports Center through traffic demand forecasting. The simulated data and road plan underwent macro prediction model technology and numerical simulation technology through Emme and TransCAD. The regional road network structure, traffic demand forecast, plane, longitudinal section, and cross-sectional program selection were investigated to determine a reasonable design program. While urban development programs were implemented, the study ensured an increase in the city's economic growth alongside the guaranteed value of citizens’ welfare.
Compared to traditional electronic maps, high-precision maps are more about providing services for vehicles. Because vehicles lack the visual recognition and logic inherent in humans, high-precision maps can assist ve...
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Compared to traditional electronic maps, high-precision maps are more about providing services for vehicles. Because vehicles lack the visual recognition and logic inherent in humans, high-precision maps can assist vehicles in identifying obstacles, vehicles, etc., and can also expand their environmental awareness capabilities. This can provide vehicles with a global perspective that other sensors cannot obtain. This article includes road, traffic, and facility information outside the sensor monitoring range. This paper analyzes and defines road design data and high-precision map construction in detail, and then verifies the progressiveness of high-precision map construction methods based on road design data compared with traditional high-precision map construction methods through experimental analysis
When a road design solution is quite out of standards for the presence of insurmountable constraints, there is the need for an objective procedure aimed at achieving a certain level of safety for drivers. To avoid iss...
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When a road design solution is quite out of standards for the presence of insurmountable constraints, there is the need for an objective procedure aimed at achieving a certain level of safety for drivers. To avoid issues on judicial responsibility, designers aim to fully satisfy the existing standards, possibly without any exception. Traditional methodologies based on previous experience or road administrators' guidelines generally caused problems due to the high subjectivity involved in the analysis. In this paper, to overpass these issues, a rational procedure based on vehicles telemetry data in a simulated environment is proposed. This process, through synthetic indices, allows the analysts to compare two road geometries, similar but different, because one includes curves with shorter residual circular arcs than threshold values imposed by Italian standards. The main results, derived from a two-way ANOVA with subsequent contrast analysis, suggest that a certain deviation respect to the standards did not determine any decay in the driver's performance. Compared to the existing literature, in this study, a full objective procedure was proposed, based on a totally new indicator, which can be easily adapted to any context, involving driver, road and vehicle at the same time.
Multi-fidelity algorithms for solving the horizontal alignment problem in road design are considered. A multi-fidelity surrogate model is built and quantile regression is used to understand its accuracy at various fid...
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Multi-fidelity algorithms for solving the horizontal alignment problem in road design are considered. A multi-fidelity surrogate model is built and quantile regression is used to understand its accuracy at various fidelity levels. Two algorithms are compared: a generalized pattern search algorithm with adaptive precision control, and a trust-region algorithm for unconstrained problems with controlled error. To make a fair comparison, the parameters of each algorithm are tuned on five small roads using performance profiles. Then the algorithms are evaluated on 35 roads, ranging from small to very large roads. The results show that using multi-fidelity surrogates in optimization algorithms provide notable speed-up when compared to single-fidelity algorithms while preserving the quality of solutions (cost error ). On the longest roads, higher speed-up and better accuracy are observed.
When building a road, it is critical to select a vertical alignment which ensures design and safety constraints. Finding such a vertical alignment is not necessarily a feasible problem, and the models describing it ge...
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When building a road, it is critical to select a vertical alignment which ensures design and safety constraints. Finding such a vertical alignment is not necessarily a feasible problem, and the models describing it generally involve a large number of variables and constraints. This paper is dedicated to rapidly proving the feasibility or the infeasibility of a Mixed Integer Linear Program (MILP) modeling the vertical alignment problem. To do so, we take advantage of the particular structure of the MILP, and we prove that only a few of the MILP's constraints determine the feasibility of the problem. In addition, we propose a method to build a feasible solution to the MILP that does not involve integer variables. This enables time saving to proving the feasibility of the vertical alignment problem and to find a feasible vertical alignment, as emphasized by numerical results. It is on average 75 times faster to prove the feasibility and 10 times faster to build a feasible solution.
We analyze the use of ℓ1-norm and Total Variation regularization within a model of road design to obtain sensible vertical alignments. With a dataset of twenty-three roads, we present a heuristic for choosing regulari...
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Traffic accidents involving pedestrians and drivers pose significant public health and safety *** the differential influences of road physical design attributes on crash frequencies for these two groups is critical fo...
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Traffic accidents involving pedestrians and drivers pose significant public health and safety *** the differential influences of road physical design attributes on crash frequencies for these two groups is critical for developing targeted safety *** that the zero-truncated characteristic of the data is uncertain,the results of the zero-truncated negative binomial models and traditional negative binomial models are calculated to seek the better *** result revealed that the road surface conditions and vertical and horizontal curvature have greater influence on both pedestrian and driver compared to number of lanes and speed *** speed limits were more pronounced for pedestrian crash frequency than driver ***,the effect of different types of intersections was stronger for driver crash *** differential influences of road physical design attributes on traffic crash frequencies for pedestrians versus drivers highlight the importance of adopting a user-centric approach to transportation safety planning and infrastructure *** interventions to address the unique needs and vulnerabilities of different road user groups can lead to more effective safety improvements and better overall traffic safety outcomes.
With increasing land transportation requirements in both urban and rural areas, roads are encroaching ever more on animal habitats, where collisions with vehicles are a leading contributor to wildlife mortality. While...
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With increasing land transportation requirements in both urban and rural areas, roads are encroaching ever more on animal habitats, where collisions with vehicles are a leading contributor to wildlife mortality. While road designers recognise the importance of accounting for such impacts at the design level, existing approaches simply either ignore viable habitat or avoid such regions entirely. Respectively, this can result in road alignments that are overly damaging to vulnerable species or prohibitively expensive to build and operate. The research presented in this paper investigates the effects of explicitly accounting for animal mortality on the design of a road through an ecologically sensitive area. The model presented achieves this by incorporating a spatially-explicit animal migration and road mortality model into an accepted optimal road alignment algorithm to propose low-cost roads that maintain the animal population above a minimum threshold by the end of a specified design horizon. The new method was applied to an example scenario to demonstrate the effect of setting a minimum required animal population on the road design. This model was able to consistently produce a road that met a minimum required species conservation benefit. This reflected a major improvement over the model that ignored animal habitats while only requiring a minor increase in construction and operating costs compared to the model that avoids habitat. (C) 2017 Elsevier Ltd. All rights reserved.
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