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The analysis of road safety is critical in road design. Complying to guidelines is not enough to ensure the highest safety levels, so many of them encourage designers to virtually recreate and test their roads, benefitting from the evolution of driving simulators in recent years. However, an accurate recreation of the road and its environment represents a real bottleneck in the process. A very important limitation lies in the diversity of input data, from different sources and requiring specific adaptations for every single simulator. This paper aims at showing a framework for recreating faster virtual scenarios by using an Industry Foundation Classes (IFC)-based file. This methodology was compared to two other conventional methods for developing driving scenarios. The main outcome of this study has demonstrated that with a data exchange file in IFC format, virtual scenarios can be faster designed to carry out safety audits with driving simulators. As a result, the editing, programming, and processing times were substantially reduced using the proposed IFC exchange file format through a BIM (Building Information Modeling) model. This methodology facilitates cost-savings, execution, and optimization resources in road safety analysis.
Juan Dols; Jaime Molina; F. Camacho-Torregrosa; David Llopis-Castelló; Alfredo García. Development of Driving Simulation Scenarios Based on Building Information Modeling (BIM) for Road Safety Analysis. Sustainability 2021, 13, 2039 .
AMA StyleJuan Dols, Jaime Molina, F. Camacho-Torregrosa, David Llopis-Castelló, Alfredo García. Development of Driving Simulation Scenarios Based on Building Information Modeling (BIM) for Road Safety Analysis. Sustainability. 2021; 13 (4):2039.
Chicago/Turabian StyleJuan Dols; Jaime Molina; F. Camacho-Torregrosa; David Llopis-Castelló; Alfredo García. 2021. "Development of Driving Simulation Scenarios Based on Building Information Modeling (BIM) for Road Safety Analysis." Sustainability 13, no. 4: 2039.
In Spain, a new challenge is emerging due to the increase of many recreational bicyclists on two-lane rural roads. These facilities have been mainly designed for motorized vehicles, so the coexistence of cyclists and drivers produces an impact, in terms of road safety and operation. In order to analyze the occurrence of crashes and enhance safety for bicycling, it is crucial to know the cycling volume. Standard procedures recommend using data from permanent stations and temporary short counts, but bicycle volumes are rarely monitored in rural roads. However, bicyclists tend to track their leisure and exercise activities with fitness apps that use GPS. In this context, this research aims at analyzing the daily and seasonal variability of the Strava Usage Rate (SUR), defined as the proportion of bicyclists using the Strava app along a certain segment on rural highways, to estimate the Annual Average Daily Bicycle (AADB) volume on rural roads. The findings of this study offer possible solutions to policy makers in terms of planning and design of the cycling network. Moreover, the use of crowdsourced data from the Strava app will potentially save costs to public agencies, since public data could replace costly counting campaigns.
Francisco Camacho-Torregrosa; David Llopis-Castelló; Griselda López-Maldonado; Alfredo García. An Examination of the Strava Usage Rate—A Parameter to Estimate Average Annual Daily Bicycle Volumes on Rural Roadways. Safety 2021, 7, 8 .
AMA StyleFrancisco Camacho-Torregrosa, David Llopis-Castelló, Griselda López-Maldonado, Alfredo García. An Examination of the Strava Usage Rate—A Parameter to Estimate Average Annual Daily Bicycle Volumes on Rural Roadways. Safety. 2021; 7 (1):8.
Chicago/Turabian StyleFrancisco Camacho-Torregrosa; David Llopis-Castelló; Griselda López-Maldonado; Alfredo García. 2021. "An Examination of the Strava Usage Rate—A Parameter to Estimate Average Annual Daily Bicycle Volumes on Rural Roadways." Safety 7, no. 1: 8.
Various studies have been recently conducted to predict pavement condition, but most of them were developed in a certain region where climate conditions were kept constant and/or the research focused on specific road distresses using single parameters. Thus, this research aimed at determining the influence of pavement structure, traffic demand, and climate factors on urban flexible pavement condition over time. To do this, the Structural Number was used as an indicator of the pavement capacity, various traffic and climate variables were defined, and the Pavement Condition Index was used as a surrogate measure of pavement condition. The analysis was focused on the calibration of regression models by using the K-Fold Cross Validation technique. As a result, for a given pavement age, pavement condition worsens as the Equivalent Single Axle Load and the Annual Average Height of Snow increased. Likewise, a cold Annual Average Temperature (5–15 °C) and a large Annual Average Range of Temperature (20–30 °C) encourage a more aggressive pavement deterioration process. By contrast, warm climates with low temperature variations, which are associated with low precipitation, lead to a longer pavement service life. Additionally, a new classification of climate zones was proposed on the basis of the weather influence on pavement deterioration.
David Llopis-Castelló; Tatiana García-Segura; Laura Montalbán-Domingo; Amalia Sanz-Benlloch; Eugenio Pellicer. Influence of Pavement Structure, Traffic, and Weather on Urban Flexible Pavement Deterioration. Sustainability 2020, 12, 9717 .
AMA StyleDavid Llopis-Castelló, Tatiana García-Segura, Laura Montalbán-Domingo, Amalia Sanz-Benlloch, Eugenio Pellicer. Influence of Pavement Structure, Traffic, and Weather on Urban Flexible Pavement Deterioration. Sustainability. 2020; 12 (22):9717.
Chicago/Turabian StyleDavid Llopis-Castelló; Tatiana García-Segura; Laura Montalbán-Domingo; Amalia Sanz-Benlloch; Eugenio Pellicer. 2020. "Influence of Pavement Structure, Traffic, and Weather on Urban Flexible Pavement Deterioration." Sustainability 12, no. 22: 9717.
Tatiana García-Segura; Laura Montalbán-Domingo; David Llopis-Castelló; Michael D. Lepech; M. Amalia Sanz; Eugenio Pellicer. Incorporating pavement deterioration uncertainty into pavement management optimization. International Journal of Pavement Engineering 2020, 1 -12.
AMA StyleTatiana García-Segura, Laura Montalbán-Domingo, David Llopis-Castelló, Michael D. Lepech, M. Amalia Sanz, Eugenio Pellicer. Incorporating pavement deterioration uncertainty into pavement management optimization. International Journal of Pavement Engineering. 2020; ():1-12.
Chicago/Turabian StyleTatiana García-Segura; Laura Montalbán-Domingo; David Llopis-Castelló; Michael D. Lepech; M. Amalia Sanz; Eugenio Pellicer. 2020. "Incorporating pavement deterioration uncertainty into pavement management optimization." International Journal of Pavement Engineering , no. : 1-12.
Road safety is a major public health concern in our society. Effective road design and accurate safety analyses must be a component of programs focused on reducing and eliminating roadway injuries and deaths. Various methodologies exist to determine the expected number of crashes on rural two-lane rural roads. This research compares different procedures which allow for the estimation of the number of crashes on homogeneous road segments. In this effort, a total of 27 two-lane rural road sections located in North Carolina were considered, resulting in 59 homogeneous road segments composed of 350 horizontal curves and 375 tangents along 150 km of road. Four methods were applied to the selected roadways: the Highway Safety Manual predictive method, two jurisdiction-specific Safety Performance Functions (SPFs), and a SPF which includes a consistency parameter. This research found that the use of SPFs which incorporate a consistency parameter allows highway engineers to consider human factor impacts on road safety assessment. The use of a consistency parameter can also simplify the crash estimation process. Analysis methods which only included local geometric variables provided unreliable results due to the calibration of only the specific road elements instead of their relationship with other road elements along homogeneous road segments.
David Llopis-Castelló; Daniel J. Findley; Alfredo García. Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency. Journal of Transportation Safety & Security 2020, 1 -22.
AMA StyleDavid Llopis-Castelló, Daniel J. Findley, Alfredo García. Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency. Journal of Transportation Safety & Security. 2020; ():1-22.
Chicago/Turabian StyleDavid Llopis-Castelló; Daniel J. Findley; Alfredo García. 2020. "Comparison of the highway safety manual predictive method with safety performance functions based on geometric design consistency." Journal of Transportation Safety & Security , no. : 1-22.
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 different calibration factors for each type of road element and each type of crash severity.
David Llopis-Castelló; Daniel Findley. Influence of Calibration Factors on Crash Prediction on Rural Two-Lane Two-Way Roadway Segments. Journal of Transportation Engineering, Part A: Systems 2019, 145, 04019024 .
AMA StyleDavid Llopis-Castelló, Daniel Findley. Influence of Calibration Factors on Crash Prediction on Rural Two-Lane Two-Way Roadway Segments. Journal of Transportation Engineering, Part A: Systems. 2019; 145 (6):04019024.
Chicago/Turabian StyleDavid Llopis-Castelló; Daniel Findley. 2019. "Influence of Calibration Factors on Crash Prediction on Rural Two-Lane Two-Way Roadway Segments." Journal of Transportation Engineering, Part A: Systems 145, no. 6: 04019024.
David Llopis-Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. Analysis of the influence of geometric design consistency on vehicle CO2 emissions. Transportation Research Part D: Transport and Environment 2019, 69, 40 -50.
AMA StyleDavid Llopis-Castelló, Francisco Javier Camacho-Torregrosa, Alfredo García. Analysis of the influence of geometric design consistency on vehicle CO2 emissions. Transportation Research Part D: Transport and Environment. 2019; 69 ():40-50.
Chicago/Turabian StyleDavid Llopis-Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. 2019. "Analysis of the influence of geometric design consistency on vehicle CO2 emissions." Transportation Research Part D: Transport and Environment 69, no. : 40-50.
Road crash occurrence is closely related to the geometric design consistency, which can be defined as how drivers’ expectancies and road behavior fit. To this regard, the crash rate on a road segment increases as its consistency level decreases. To assess this phenomenon, inertial consistency models were recently developed. These models are based on the difference between the inertial operating speed, which represents drivers’ expectancies, and the operating speed, which represents road behavior. The higher the difference between both speeds, the higher the likelihood of crash occurrence. This research aims to validate and calibrate these consistency models on American two-lane rural roads. For this, a total of 194 homogeneous road segments and 977 horizontal curves along 665 km in North Carolina (US) were used. As a result, the geometric design consistency was identified as a major factor of crash occurrence. The higher the difference between drivers’ expectancies and road behavior, the higher the crash rate. Likewise, the greater the consistency level, the greater the percentage of horizontal curves without reported crashes. A Safety Performance Function was also calibrated to estimate the number of crashes on a road segment. Consistency thresholds were defined and tested to identify where these crashes are more likely to take place. Finally, the results obtained in this study were compared with those obtained previously on Spanish highways. To this regard, the crash rate on an American highway was 1.85 times greater than those observed on a Spanish highway under the same risk exposure and consistency conditions. Therefore, different tools were developed to enhance the assessment of road safety to the geometric design of both new two-lane rural roads and improvements of existing highways.
David Llopis-Castelló; Daniel J. Findley; Francisco Javier Camacho-Torregrosa; Alfredo García. Calibration of inertial consistency models on North Carolina two-lane rural roads. Accident Analysis & Prevention 2019, 127, 236 -245.
AMA StyleDavid Llopis-Castelló, Daniel J. Findley, Francisco Javier Camacho-Torregrosa, Alfredo García. Calibration of inertial consistency models on North Carolina two-lane rural roads. Accident Analysis & Prevention. 2019; 127 ():236-245.
Chicago/Turabian StyleDavid Llopis-Castelló; Daniel J. Findley; Francisco Javier Camacho-Torregrosa; Alfredo García. 2019. "Calibration of inertial consistency models on North Carolina two-lane rural roads." Accident Analysis & Prevention 127, no. : 236-245.
Federica Nobili; Francesco Bella; David Llopis Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. Environmental effects of road geometric and operational features. Transportation Research Procedia 2019, 37, 385 -392.
AMA StyleFederica Nobili, Francesco Bella, David Llopis Castelló, Francisco Javier Camacho-Torregrosa, Alfredo García. Environmental effects of road geometric and operational features. Transportation Research Procedia. 2019; 37 ():385-392.
Chicago/Turabian StyleFederica Nobili; Francesco Bella; David Llopis Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. 2019. "Environmental effects of road geometric and operational features." Transportation Research Procedia 37, no. : 385-392.
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.
David Llopis-Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. Calibration of the inertial consistency index to assess road safety on horizontal curves of two-lane rural roads. Accident Analysis & Prevention 2018, 118, 1 -10.
AMA StyleDavid Llopis-Castelló, Francisco Javier Camacho-Torregrosa, Alfredo García. Calibration of the inertial consistency index to assess road safety on horizontal curves of two-lane rural roads. Accident Analysis & Prevention. 2018; 118 ():1-10.
Chicago/Turabian StyleDavid Llopis-Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. 2018. "Calibration of the inertial consistency index to assess road safety on horizontal curves of two-lane rural roads." Accident Analysis & Prevention 118, no. : 1-10.
The most important factors for road crash occurrence are infrastructure, vehicle, and human factors. In fact, infrastructure and its interaction with human factor have been thoroughly studied in recent years through geometric design consistency, which can be defined as how drivers’ expectations and road behavior relate. Global consistency models were calibrated in the last decade to assess road safety on an entire homogeneous road segment. However, none of them include the underlying consistency phenomenon in their formulation. Recently, a new model was developed based on the difference between the inertial operating speed profile, which represents drivers’ expectancies, and the operating speed profile, which represents road behavior. While the operating speed represents the estimated operating speed for every location along the road, the inertial operating speed aggregates for every station the operating speed effect along some distance already covered by drivers. The authors hypothesized that this ‘aggregation effect’ was connected to drivers’ expectancies, which proved to be true based on the best model fitted. However, the exact distance (or time) that should be considered to estimate the inertial operating speed still remains unknown. This paper aims to complete this model, analyzing how the inertial operating speed varies depending on different distances and periods of time. This impact is measured considering the reliability of the corresponding consistency model. The paper also covers how the inertial operating speed should be determined along the final distance or time. For this, a total of 184 homogeneous road segments along 650 km in Spain were used.
David Llopis-Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. Development of a global inertial consistency model to assess road safety on Spanish two-lane rural roads. Accident Analysis & Prevention 2018, 119, 138 -148.
AMA StyleDavid Llopis-Castelló, Francisco Javier Camacho-Torregrosa, Alfredo García. Development of a global inertial consistency model to assess road safety on Spanish two-lane rural roads. Accident Analysis & Prevention. 2018; 119 ():138-148.
Chicago/Turabian StyleDavid Llopis-Castelló; Francisco Javier Camacho-Torregrosa; Alfredo García. 2018. "Development of a global inertial consistency model to assess road safety on Spanish two-lane rural roads." Accident Analysis & Prevention 119, no. : 138-148.
Road crashes are mainly caused by three concurrent factors: infrastructure, vehicle, and human factors. The interaction between the infrastructure and human factors leads to the concept of geometric design consistency. Recently, a global consistency model was developed based on the difference between the inertial operating speed profile and the operating speed profile. The first was defined as the weighted average operating speed of the previous road section based on distance, and represents drivers’ expectancies, whereas the second represents road behavior. However, drivers’ expectancies are related to short-term memory which declines gradually and depends on time. Thus, a time-based inertial operating speed would allow a more accurate estimation of the phenomenon. This research analyzes different periods of time and weighting distributions to identify how drivers’ expectancies should be estimated. A set of 71 homogeneous road segments located in Italy were considered in the study. As a result, 25 seconds and a convex parabolic distribution should be used to calculate the inertial operating speed profile. This new way of estimating drivers’ expectancies showed better results than those obtained based on distance. Finally, the proposed consistency model was compared with the previous models and was found to be able to assess more accurately the geometric design consistency. Therefore, the proposed consistency model is a useful tool for engineers to estimate the number of crashes so that they can incorporate road safety considerations into the geometric design of either new two-lane rural roads, or improving the existing ones.
David Llopis Castelló; Francesco Bella; Francisco Javier Camacho Torregrosa; Alfredo García. Time-Based Calibration of the Inertial Operating Speed to Enhance the Assessment of the Geometric Design Consistency. Transportation Research Record: Journal of the Transportation Research Board 2018, 2672, 223 -232.
AMA StyleDavid Llopis Castelló, Francesco Bella, Francisco Javier Camacho Torregrosa, Alfredo García. Time-Based Calibration of the Inertial Operating Speed to Enhance the Assessment of the Geometric Design Consistency. Transportation Research Record: Journal of the Transportation Research Board. 2018; 2672 (38):223-232.
Chicago/Turabian StyleDavid Llopis Castelló; Francesco Bella; Francisco Javier Camacho Torregrosa; Alfredo García. 2018. "Time-Based Calibration of the Inertial Operating Speed to Enhance the Assessment of the Geometric Design Consistency." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 38: 223-232.
Road safety is closely related to geometric design consistency, which is usually assessed by examining operating speed. Most consistency models only consider passenger car speeds, even though the interaction between passenger cars and heavy vehicles plays a pivotal role in road safety. This is due to the fact that there are too few models to estimate heavy vehicle speeds. This study aims to develop speed prediction models for heavy vehicles on horizontal curves of two-lane rural roads. To do this, continuous speed profiles were collected by using Global Positioning System (GPS) tracking devices on 11 road sections. Truck speeds were analyzed on 105 horizontal curves. The results showed that the radius of the horizontal curve and the grade at the point of curvature have a significant influence on heavy vehicle speeds. In this regard, vertical alignment only has a significant effect on truck speeds along upgrades. In addition, different trends were identified for loaded and unloaded trucks, so different speed models were calibrated for each of them. As a result, heavy vehicle speeds were adversely affected by grades greater than 3%. This phenomenon was larger for loaded trucks than for unloaded ones. Finally, the calibrated 85th and 15th percentile speed models were compared with those developed previously. As a conclusion, the use of the proposed models in this study was recommended on Spanish two-lane rural roads due mainly to the different characteristics of heavy vehicles around the world.
David Llopis-Castelló; Brayan González-Hernández; Ana María Pérez-Zuriaga; Alfredo Garcia. Speed Prediction Models for Trucks on Horizontal Curves of Two-Lane Rural Roads. Transportation Research Record: Journal of the Transportation Research Board 2018, 2672, 72 -82.
AMA StyleDavid Llopis-Castelló, Brayan González-Hernández, Ana María Pérez-Zuriaga, Alfredo Garcia. Speed Prediction Models for Trucks on Horizontal Curves of Two-Lane Rural Roads. Transportation Research Record: Journal of the Transportation Research Board. 2018; 2672 (17):72-82.
Chicago/Turabian StyleDavid Llopis-Castelló; Brayan González-Hernández; Ana María Pérez-Zuriaga; Alfredo Garcia. 2018. "Speed Prediction Models for Trucks on Horizontal Curves of Two-Lane Rural Roads." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 17: 72-82.
Road crashes are mainly caused by three concurrent factors: infrastructure, vehicles, and human factors. The interaction between infrastructure and human factors leads to the concept of geometric design consistency, which can be defined as how drivers’ expectations and road behavior fit. This paper presents a new global consistency model based on the difference between the inertial operating speed profile (Vi) and the operating speed profile (V85). The first is calculated as the weighted average speed of the previous road section and represents drivers’ expectations, whereas the second represents road behavior. A set of 71 homogeneous two-lane rural road segments located in Italy were used in the calibration of the model. As a result, a safety performance function based on this new consistency model was proposed to estimate the number of crashes on an entire road segment. Finally, the new model was compared with previous global consistency models, concluding that the new consistency parameter better explains the phenomenon than the previous ones. Therefore, the new consistency model is a useful tool for engineers that allows estimation of the number of crashes and incorporates road safety into the geometric design of both new two-lane rural roads and improvements to existing highways.
David Llopis-Castelló; Francesco Bella; Francisco Javier Camacho Torregrosa; Alfredo García. New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation. Journal of Transportation Engineering, Part A: Systems 2018, 144, 04018006 .
AMA StyleDavid Llopis-Castelló, Francesco Bella, Francisco Javier Camacho Torregrosa, Alfredo García. New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation. Journal of Transportation Engineering, Part A: Systems. 2018; 144 (4):04018006.
Chicago/Turabian StyleDavid Llopis-Castelló; Francesco Bella; Francisco Javier Camacho Torregrosa; Alfredo García. 2018. "New Consistency Model Based on Inertial Operating Speed Profiles for Road Safety Evaluation." Journal of Transportation Engineering, Part A: Systems 144, no. 4: 04018006.
David Llopis-Castelló; Ana María Pérez-Zuriaga; Francisco Javier Camacho Torregrosa; Alfredo García. Impact of horizontal geometric design of two-lane rural roads on vehicle co 2 emissions. Transportation Research Part D: Transport and Environment 2018, 59, 46 -57.
AMA StyleDavid Llopis-Castelló, Ana María Pérez-Zuriaga, Francisco Javier Camacho Torregrosa, Alfredo García. Impact of horizontal geometric design of two-lane rural roads on vehicle co 2 emissions. Transportation Research Part D: Transport and Environment. 2018; 59 ():46-57.
Chicago/Turabian StyleDavid Llopis-Castelló; Ana María Pérez-Zuriaga; Francisco Javier Camacho Torregrosa; Alfredo García. 2018. "Impact of horizontal geometric design of two-lane rural roads on vehicle co 2 emissions." Transportation Research Part D: Transport and Environment 59, no. : 46-57.
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.
David Llopis Castelló; Francisco Javier Camacho Torregrosa; Javier Marín-Morales; Ana María Pérez-Zuriaga; Alfredo García; Juan F. Dols. Validation of a Low-Cost Driving Simulator Based on Continuous Speed Profiles. Transportation Research Record: Journal of the Transportation Research Board 2016, 2602, 104 -114.
AMA StyleDavid Llopis Castelló, Francisco Javier Camacho Torregrosa, Javier Marín-Morales, Ana María Pérez-Zuriaga, Alfredo García, Juan F. Dols. Validation of a Low-Cost Driving Simulator Based on Continuous Speed Profiles. Transportation Research Record: Journal of the Transportation Research Board. 2016; 2602 (1):104-114.
Chicago/Turabian StyleDavid Llopis Castelló; Francisco Javier Camacho Torregrosa; Javier Marín-Morales; Ana María Pérez-Zuriaga; Alfredo García; Juan F. Dols. 2016. "Validation of a Low-Cost Driving Simulator Based on Continuous Speed Profiles." Transportation Research Record: Journal of the Transportation Research Board 2602, no. 1: 104-114.
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.
Elena García-Jiménez; Ana María Pérez-Zuriaga; David Llopis Castelló; Francisco Javier Camacho Torregrosa; Alfredo García. Examination of the Free-Flow Speed Distribution on Two-Lane Rural Roads. Transportation Research Record: Journal of the Transportation Research Board 2016, 2556, 86 -97.
AMA StyleElena García-Jiménez, Ana María Pérez-Zuriaga, David Llopis Castelló, Francisco Javier Camacho Torregrosa, Alfredo García. Examination of the Free-Flow Speed Distribution on Two-Lane Rural Roads. Transportation Research Record: Journal of the Transportation Research Board. 2016; 2556 (1):86-97.
Chicago/Turabian StyleElena García-Jiménez; Ana María Pérez-Zuriaga; David Llopis Castelló; Francisco Javier Camacho Torregrosa; Alfredo García. 2016. "Examination of the Free-Flow Speed Distribution on Two-Lane Rural Roads." Transportation Research Record: Journal of the Transportation Research Board 2556, no. 1: 86-97.
The occurrence of road crashes depends on several factors, with design consistency (i.e., conformance of highway geometry to drivers' expectations) being one of the most important. A new consistency model for evaluating the performance of tangent-to-curve transitions on two-lane rural roads was developed. This model was based on the inertial consistency index (ICI) defined for each transition. The ICI was calculated at the beginning point of the curve as the difference between the average operating speed on the previous 1-km road segment (inertial operating speed) and the actual operating speed at this point. For the calibration of the ICI and its thresholds, 88 road segments, which included 1,686 tangent-to-curve transitions, were studied. The relationship between those results and the crash rate associated with each transition was analyzed. The results showed that the higher the ICI was, the higher the crash rate; thus, the probability of accidents increased. Similar results were obtained from the study of the relationship between the ICI and the weighted average crash rate of the corresponding group of transitions. A graphical and statistical analysis established that road consistency might be considered good when the ICI was lower than 10 km/h, poor when the ICI was higher than 20 km/h, and fair otherwise. A validation process that considered 20 road segments was performed. The ICI values obtained were highly correlated to the number of crashes that had occurred at the analyzed transitions. Thus, the ICI and its consistency thresholds resulted in a new approach for evaluation of consistency.
Alfredo García; David Llopis Castelló; Francisco Javier Camacho Torregrosa; Ana María Pérez-Zuriaga. New Consistency Index Based on Inertial Operating Speed. Transportation Research Record: Journal of the Transportation Research Board 2013, 2391, 105 -112.
AMA StyleAlfredo García, David Llopis Castelló, Francisco Javier Camacho Torregrosa, Ana María Pérez-Zuriaga. New Consistency Index Based on Inertial Operating Speed. Transportation Research Record: Journal of the Transportation Research Board. 2013; 2391 (1):105-112.
Chicago/Turabian StyleAlfredo García; David Llopis Castelló; Francisco Javier Camacho Torregrosa; Ana María Pérez-Zuriaga. 2013. "New Consistency Index Based on Inertial Operating Speed." Transportation Research Record: Journal of the Transportation Research Board 2391, no. 1: 105-112.