Use of Heading Direction for Recreating the Horizontal Alignment of an Existing Road

This article proposes a new method for fit- ting the horizontal alignment of a road to a set of (x, y) points. Those points can be obtained from digital im- agery or GPS-data collection. Unlike current methods that represent road alignment through its curvature, the proposed method describes the horizontal alignment as a sequence of headings. An analytic–heuristic approach is introduced. The proposed method produces unique solu- tions even for complex horizontal alignments. Some ex- amples and a case study are presented. This solution may not be accurate enough for road redesign, but it allows researchers and departments of transportation to obtain accurate geometric featuresCamacho Torregrosa, FJ.; Pérez Zuriaga, AM.; Campoy Ungria, JM.; García García, A.; Tarko, A. (2015). Use of Heading Direction for Recreating the Horizontal Alignment of an Existing Road. Computer-Aided Civil and Infrastructure Engineering. 30(4):282-299. doi:10.1111/mice.12094S282299304Awuah-Baffour, R., Sarasua, W., Dixon, K. K., Bachman, W., & Guensler, R. (1997). Global Positioning System with an Attitude: Method for Collecting Roadway Grade and Superelevation Data. Transportation Research Record: Journal of the Transportation Research Board, 1592(1), 144-150. doi:10.3141/1592-17Ben-Arieh, D., Chang, S., Rys, M., & Zhang, G. (2004). Geometric Modeling of Highways Using Global Positioning System Data andB-Spline Approximation. Journal of Transportation Engineering, 130(5), 632-636. doi:10.1061/(asce)0733-947x(2004)130:5(632)Bosurgi, G., & D’Andrea, A. (2012). A Polynomial Parametric Curve (PPC-CURVE) for the Design of Horizontal Geometry of Highways. Computer-Aided Civil and Infrastructure Engineering, 27(4), 304-a312. doi:10.1111/j.1467-8667.2011.00750.xCai, H., & Rasdorf, W. (2008). Modeling Road Centerlines and Predicting Lengths in 3-D Using LIDAR Point Cloud and Planimetric Road Centerline Data. Computer-Aided Civil and Infrastructure Engineering, 23(3), 157-173. doi:10.1111/j.1467-8667.2008.00518.xCastro, M., Iglesias, L., Rodríguez-Solano, R., & Sánchez, J. A. (2006). Geometric modelling of highways using global positioning system (GPS) data and spline approximation. Transportation Research Part C: Emerging Technologies, 14(4), 233-243. doi:10.1016/j.trc.2006.06.004Dong, H., Easa, S. M., & Li, J. (2007). Approximate Extraction of Spiralled Horizontal Curves from Satellite Imagery. Journal of Surveying Engineering, 133(1), 36-40. doi:10.1061/(asce)0733-9453(2007)133:1(36)Easa, S. M., Dong, H., & Li, J. (2007). Use of Satellite Imagery for Establishing Road Horizontal Alignments. Journal of Surveying Engineering, 133(1), 29-35. doi:10.1061/(asce)0733-9453(2007)133:1(29)Hummer , J. E. Rasdorf , W. J. Findley , D. J. Zegeer , C. V. Sundstrom , C. A. 2010 Procedure for Curve Warning Signing, Delineation, and Advisory Speeds for Horizontal Curves http://ntl.bts.gov/lib/38000/38400/38476/2009--07finalreport.pdfImran, M., Hassan, Y., & Patterson, D. (2006). GPS-GIS-Based Procedure for Tracking Vehicle Path on Horizontal Alignments. Computer-Aided Civil and Infrastructure Engineering, 21(5), 383-394. doi:10.1111/j.1467-8667.2006.00444.xLi, Z., Chitturi, M. V., Bill, A. R., & Noyce, D. A. (2012). Automated Identification and Extraction of Horizontal Curve Information from Geographic Information System Roadway Maps. Transportation Research Record: Journal of the Transportation Research Board, 2291(1), 80-92. doi:10.3141/2291-10Othman, S., Thomson, R., & Lannér, G. (2012). Using Naturalistic Field Operational Test Data to Identify Horizontal Curves. Journal of Transportation Engineering, 138(9), 1151-1160. doi:10.1061/(asce)te.1943-5436.0000408Zuriaga, A. M. P., García, A. G., Torregrosa, F. J. C., & D’Attoma, P. (2010). Modeling Operating Speed and Deceleration on Two-Lane Rural Roads with Global Positioning System Data. Transportation Research Record: Journal of the Transportation Research Board, 2171(1), 11-20. doi:10.3141/2171-02Roh, T.-H., Seo, D.-J., & Lee, J.-C. (2003). An accuracy analysis for horizontal alignment of road by the kinematic GPS/GLONASS combination. KSCE Journal of Civil Engineering, 7(1), 73-79. doi:10.1007/bf02841990Shafahi, Y., & Bagherian, M. (2012). A Customized Particle Swarm Method to Solve Highway Alignment Optimization Problem. Computer-Aided Civil and Infrastructure Engineering, 28(1), 52-67. doi:10.1111/j.1467-8667.2012.00769.xTsai, Y. (James), Wu, J., Wang, Z., & Hu, Z. (2010). Horizontal Roadway Curvature Computation Algorithm Using Vision Technology. Computer-Aided Civil and Infrastructure Engineering, 25(2), 78-88. doi:10.1111/j.1467-8667.2009.00622.

DEVELOPMENT AND CALIBRATION OF A GLOBAL GEOMETRIC DESIGN CONSISTENCY MODEL FOR TWO-LANE RURAL HIGHWAYS, BASED ON THE USE OF CONTINUOUS OPERATING SPEED PROFILES

Road safety is one of the most important problems in our society. It causes hundreds of fatalities every year worldwide. A road accident may be caused by several concurrent factors. The most common are human and infrastructure. Their interaction is important too, which has been studied in-depth for years. Therefore, there is a better knowledge about the driving task. In several cases, these advances are still not included in road guidelines. Some of these advances are centered on explaining the underlying cognitive processes of the driving task. Some others are related to the analysis of drivers’ response or a better estimation of road crashes. The concept of design consistency is related to all of them. Road design consistency is the way how road alignment fits drivers’ expectancies. Hence, drivers are surprised at inconsistent roads, presenting a higher crash risk potential. This PhD presents a new, operating speed-based global consistency model. It is based on the analysis of more than 150 two-lane rural homogeneous road segments of the Valencian Region (Spain). The final consistency parameter was selected as the combination of operational parameters that best estimated the number of crashes. Several innovative auxiliary tools were developed for this process. One example is a new tool for recreating the horizontal alignment of two-lane rural roads by means of an analytic-heuristic process. A new procedure for determining road homogeneous segments was also developed, as well as some expressions to accurately determine the most adequate design speed. The consistency model can be integrated into safety performance functions in order to estimate the amount of road crashes. Finally, all innovations are combined into a new road design methodology. This methodology aims to complement the existing guidelines, providing to road safety a continuum approach and giving the engineers tools to estimate how safe are their road designs.Camacho Torregrosa, FJ. (2015). DEVELOPMENT AND CALIBRATION OF A GLOBAL GEOMETRIC DESIGN CONSISTENCY MODEL FOR TWO-LANE RURAL HIGHWAYS, BASED ON THE USE OF CONTINUOUS OPERATING SPEED PROFILES [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48543TESI

Procedure for the Identification of Existing Roads Alignment from Georeferenced Points Database

The aim of this research is to look for an automated, economical and fast method able to identify the elements of an existing road layout, whose original geometric design could date back to distant ages and could have undergone major modifications over the years. The analysis has been directed towards the Italian two-lane rural roads; the national public company ANAS made available its graph, obtained from high-performance surveys, that represents about 90% of these roads’ network. The graph is made up of a collection of georeferenced points but does not recognize or describe the geometric elements making up the roadway. Consequently, it has been necessary to design and develop an original procedure, subsequently implemented in a programming platform, able to identify the characteristics of the several parts, which constitute the reference axes of the existing roads. This research focuses on the horizontal geometry assessing the coherence, consistency and homogeneity of the roads’ layout, through the ex post application of the regulatory model for the design verification. If road sections are identified in which some conditions are not significantly met, further investigation should be conducted in order to ensure road safety and to plan any road upgrading activities

Impact of horizontal geometric design of two-lane rural roads on vehicle CO2 emissions

[EN] In 2014, highway vehicles accounted for 72.8% of all Greenhouse Gases emissions from transportation in Europe. In the United States (US), emissions follow a similar trend. Although many initiatives try to mitigate emissions by focusing on traffic operations, little is known about the relationship between emissions and road design. It is feasible that some designs may increase average flow speed and reduce accelerations, consequently minimizing emissions. This study aims to evaluate the impact of road horizontal alignment on CO2 emissions produced by passenger cars using a new methodology based on naturalistic data collection. Individual continuous speed profiles were collected from actual drivers along eleven two-lane rural road sections that were divided into 29 homogeneous road segments. The CO2 emission rate for each homogeneous road segment was estimated as the average of CO2 emission rates of all vehicles driving, estimated by applying the VT-Micro model. The analysis concluded that CO2 emission rates increase with the Curvature Change Rate. Smooth road segments normally allowed drivers to reach higher speeds and maintain them with fewer accelerations. Additionally, smother segments required less time to cover the same distance, so emissions per length were lower. It was also observed that low mean speeds produce high CO2 emission rates and they increase even more on roads with high speed dispersions. Based on this data, several regression models were calibrated for different vehicle types to estimate CO2 emissions on a specific road segment. These results could be used to incorporate sustainability principles to highway geometric design.The study presented in this paper is part of the research project titled "CASEFU - Estudio experimental de la funcionalidad y seguridad de las carreteras convencionales" (TRA2013-42578-P), subsidized by the Spanish Ministry of Economy, Industry, and Competitiveness and the European Social Fund. In addition, the authors would like to thank the Center for Studies and Experimentation of Public Works (CEDEX) of the Spanish Ministry of Public Works for subsidizing the field data collection and the General Directorate of Public Works and Transportation of the Valencian Government, to the Road Department of the Valencian Provincial Council, and to the Spanish Ministry of the Interior, especially the General Directorate of Traffic of Spain, for their cooperation in field data gathering. Finally, we would like to thank Professor Hesham A. Rakha, Virginia Tech (USA), for providing the VT-Micro model and assessing the authors in its use to obtain outcomes.Llopis-Castelló, D.; Pérez Zuriaga, AM.; Camacho-Torregrosa, FJ.; García García, A. (2018). Impact of horizontal geometric design of two-lane rural roads on vehicle CO2 emissions. Transportation Research Part D Transport and Environment. 59:46-57. https://doi.org/10.1016/j.trd.2017.12.020S46575

Operating Speed models for heavy vehicles on tangents of Spanish two-lane rural roads

Road safety is one of the most important public health concern in our society. In Spain, the most of the traffic accidents involving a heavy vehicle occur on two-lane rural roads. Current consistency models only rely on the analysis of the operating speed profile for passenger cars due to the few speed models available for heavy vehicles. Therefore, the main objective of this research was to analyze and model the free flow speed developed by heavy vehicles on tangents of two-lane rural roads. Thus, this research presents new speed models for estimating heavy vehicle speeds on tangents of two-lane rural roads. To do this, truck speeds were collected by means of Global Positioning System tracking devices, on 49 tangents sections that were identified from 12 road sections. Two different patterns were detected, which were associated with loaded and unloaded trucks. The combined effect of geometric and operational variables was analyzed. As a result, the most influential variables on loaded truck speeds were the speed of the preceding horizontal curve and the grade of the tangent, whereas unloaded truck speeds were significantly influenced by the length of the tangent and the speed of the preceding horizontal curve. Finally, several regression models were calibrated to predict the 85th and 15th percentile speeds for both loaded and unloaded trucks

Influence of Calibration Factors on Crash Prediction on Rural Two-Lane, Two-Way Roadway Segments

[EN] Calibration factors are applied in the Highway Safety Manual predictive method for rural two-lane, two-way roadway segments to adjust the estimate for local conditions. This research aims to evaluate and recommend improvements related to the estimation of these calibration factors. An aggregated and disaggregated analysis was performed to study the influence of different calibration factors on the prediction of the number of crashes in North Carolina. As a result, those calibration factors based on both types of road elements (horizontal curves and tangents) led to overestimating and underestimating the number of crashes on tangents and horizontal curves, respectively. Furthermore, the calibration factors based on fatal-and-injury crashes allowed a more accurate estimation of the predicted number of crashes than those calibrated considering all severity levels. Therefore, it is recommended to apply a different calibration factors for each type of road element and each type of crash severity.This research was subsidized by the Spanish Ministry of Economy, Industry, and Competitiveness through "Ayudas a la movilidad predoctoral para la realizacion de estancias breves en centros de I+D 2016." In addition, the authors would like to thank the North Carolina Department of Transportation (NCDOT), which provided traffic and crash data.Llopis-Castelló, D.; Findley, DJ. (2019). Influence of Calibration Factors on Crash Prediction on Rural Two-Lane, Two-Way Roadway Segments. Journal of Transportation Engineering. 145(6):04019024-1-04019024-9. https://doi.org/10.1061/JTEPBS.000024504019024-104019024-9145

Validation of Low-Cost Driving Simulator Based on Continuous Speed Profiles

[EN] The number of road safety studies that are based on driving simulators is growing significantly. The Polytechnic University of Valencia, Spain, developed a low-cost driving simulator for the assessment, training, and rehabilitation of drivers (SE2RCO). The main objective of this research was the validation of the driving simulator so that studies about road safety and highway geometric design that considered human factors could be performed. The validation was based on continuous speed profiles collected from 28 volunteers on a 30-km-long, two-lane rural road section. The same volunteers drove through the same road section built in SE2RCO. Speed data of 79 curves and 52 tangents were selected for the analysis. Comparison of the real and simulated speeds ensured the simulator's objective validity according to average and operating speeds. Two models were developed to predict field speeds from simulated speeds. Results showed that a simulated average speed lower than approximately 90 km/h was linked to a similar real average speed. For higher simulated speeds, the average speed in the real environment was lower than the simulated one. In addition, the actual operating speed was around 5 km/h lower than the operating speed in the driving simulator. Most volunteers assessed the quality and similarity of the virtual environment compared with the real world as medium or high and assessed the driving tasks similarly, thus achieving subjective validation of the simulator.The authors thank the Polytechnic University of Valencia, which subsidized the research project CONSIM-Desarrollo de un Modelo para la Evaluacion de la Consistencia del Diseno Geometric de Carreteras Convencionales Mediante Simuladores de Conduccion. The study presented here was also part of the research project titled CASEFU-Estudio Experimental de la Funcionalidad y Seguridad de las Carreteras Convencionales, which was subsidized by the Spanish Ministry of Economy and Competitiveness and the European Social Fund.Llopis-Castelló, D.; Camacho Torregrosa, FJ.; Marín-Morales, J.; Pérez Zuriaga, AM.; García García, A.; Dols Ruiz, JF. (2016). Validation of Low-Cost Driving Simulator Based on Continuous Speed Profiles. Transportation Research Record Journal of the Transportation Research Board. 2602:104-114. https://doi.org/10.3141/2602-13S104114260

How to incorporate automated vehicles on Road Safety Audits

[EN] Road Safety Audit (RSA) has proved to be one of the best road safety management procedures for design, construction, and maintenance of existing and new road infrastructure. At the beginning, the safety review only focused on motor vehicles and the human driver. Later, as well as nowadays, procedures are also applied to the needs for all vulnerable road users, taking into account that each of the groups (pedestrians, cyclists, motorcyclists) has its own specific requirements. The new and better capabilities of automated vehicles should be in accordance to road technical features, such as geometry, sight distance, signs, and markings. However, the corresponding standards were developed for human driving, and therefore they must be adapted to the new systems without losing compatibility with lower automation levels. While considerable research effort has been carried out for the digital infrastructure, only some studies have been carried out for the physical one with interesting findings that deserve to be incorporated into RSA procedures, such as: new available and required stopping sight distance; new automated speed as the maximum speed that allows the automated system to maintain the longitudinal and lateral control; readable road markings and road signs to facilitate recognition by both human drivers and connected and automated vehicles; etc. The main objective is to achieve the optimal performance of Advanced Driver Assistance Systems (ADAS). The main result of this study is a first proposal for a new chapter to be included in the checklists to carry out road safety audits for the different stages and road safety inspections.Camacho-Torregrosa, FJ.; García García, A.; Llopis-Castelló, D. (2021). How to incorporate automated vehicles on Road Safety Audits. Universidad de Burgos. 3113-3134. http://hdl.handle.net/10251/1913473113313

Calibration of the inertial consistency index to assess road safety on horizontal curves of two-lane rural roads

[EN] One of every four road fatalities occurs on horizontal curves of two-lane rural roads. To this regard, many studies have been undertaken to analyze the crash risk on this road element. Most of them were based on the concept of geometric design consistency, which can be defined as how drivers¿ expectancies and road behavior relate. However, none of these studies included a variable which represents and estimates drivers¿ expectancies. This research presents a new local consistency model based on the Inertial Consistency Index (ICI). This consistency parameter is defined as the difference between the inertial operating speed, which represents drivers¿ expectations, and the operating speed, which represents road behavior. The inertial operating speed was defined as the weighted average operating speed of the preceding road section. In this way, different lengths, periods of time, and weighting distributions were studied to identify how the inertial operating speed should be calculated. As a result, drivers¿ expectancies should be estimated considering 15¿s along the segment and a linear weighting distribution. This was consistent with drivers¿ expectancies acquirement process, which is closely related to Short-Term Memory. A Safety Performance Function was proposed to predict the number of crashes on a horizontal curve and consistency thresholds were defined based on the ICI. To this regard, the crash rate increased as the ICI increased. Finally, the proposed consistency model was compared with previous models. As a conclusion, the new Inertial Consistency Index allowed a more accurate estimation of the number of crashes and a better assessment of the consistency level on horizontal curves. Therefore, highway engineers have a new tool to identify where road crashes are more likely to occur during the design stage of both new two-lane rural roads and improvements of existing highways.The study presented in this paper is part of the research project titled "CASEFU - Estudio experimental de la funcionalidad y seguridad de las carreteras convencionales" (TRA2013-42578-P), subsidized by the Spanish Ministry of Economy, Industry and Competitiveness and the European Social Fund. In addition, the authors would like to thank the Department of Housing, Public Works and Spatial Planning of the Valencian Regional Government and the Traffic Department of the Spanish Government, which provided traffic and crash data, respectively.Llopis-Castelló, D.; Camacho-Torregrosa, FJ.; García García, A. (2018). Calibration of the inertial consistency index to assess road safety on horizontal curves of two-lane rural roads. Accident Analysis & Prevention. 118(September 2018):1-10. https://doi.org/10.1016/j.aap.2018.05.014S110118September 201

Examination Free-Flow Speed Distribution on Two-Lane Rural Roads

[EN] Free-flow speed variation of passenger vehicles along a road segment is one of the most used factors in road safety studies, as a surrogate measure to evaluate road design consistency. Free-flow speed may be measured when a road segment is already built but must be estimated during the design phase. Several studies have been carried out to calibrate models to estimate free-flow speed, with geometric features as explanatory variables. Currently, most free-flow speed models focus only on mean speed or speed in particular percentiles, such as the 85th or 95th. Moreover, most studies have assumed normality in the free-flow speed distribution without checking this hypothesis. The main objective of this study was to analyze the free-flow speed distribution on two-lane rural road curves and tangents. The research focused on two main issues: determining whether speed data were normally distributed at a specific site and analyzing the behavior of the mean and standard deviation of speed on curves and tangents. The study was based on continuous operating speed profiles, which were obtained from a database of more than 16,000 vehicles/km. A total of 63 horizontal curves and 78 tangents were analyzed. According to the results, the normal distribution is not the best distribution in most cases for describing free-flow speeds. In 46 of the curves and 64 of the tangents, free-flow speed cannot be assumed to be normally distributed. Therefore, some other distributions should be tested in further research.The study presented in this paper is part of the research project CASEFU-Estudio experimental de la funcionalidad y seguridad de las carreteras convencionales, subsidized by the Spanish Ministry of Economy and Competitiveness and the European Social Fund. In addition, the authors thank the Center for Studies and Experimentation of Public Works of the Spanish Ministry of Public Works for subsidizing the field data collection, and the Infrastructure and Transportation Department of the General Directorate of Public Works of the Valencian Government, the Valencian Provincial Council, and the Ministry of the Interior, especially the General Directorate of Traffic of Spain, for their cooperation in gathering the field data.García Jiménez, ME.; Pérez Zuriaga, AM.; Llopis-Castelló, D.; Camacho Torregrosa, FJ.; García García, A. (2016). Examination Free-Flow Speed Distribution on Two-Lane Rural Roads. Transportation Research Record Journal of the Transportation Research Board. 2556:86-97. https://doi.org/10.3141/2556-09S8697255