SIGHT DISTANCE ANALYSIS OF HIGHWAYS USING GIS TOOLS

SIGHT DISTANCE ANALYSIS OF HIGHWAYS USING GIS TOOLS. Castro, M., Iglesias, L., Sánchez, J. A., Ambrosio, L. Transportation Research Part C: Emerging Technologies, 19 (6), 997-1005. 2011.

Abstract

Analyzing the distance visible to a driver on the highway is important for traffic safety, especially in maneuvers such as emergency stops, when passing another vehicle or when vehicles cross at intersections. This analysis is necessary not only in the design phase of highways, but also when they are in service. For its use in this last phase, a procedure supported by a Geographic Information System (GIS) has been implemented that determines the highway distances visible to the driver. The use of a GIS allows the sight distance analysis to be integrated with other analyses related to traffic safety, such as crash and design consistency analyses. In this way, more complete analyses could be made and costs shared. Additionally, with the procedure proposed it is possible to use data regarding the trajectory of a vehicle obtained on a highway with a Global Positioning System (GPS) device. This application is very useful when highway design data are not available. The procedure developed and its application in a case study are presented in this article.

Highlights

► A procedure for sight distance calculation when highway design data are unavailable.
► Integration of sight distance calculation with other road safety analyses.
► Sight distance calculations could use the most recent and detailed data available.

Keywords: Highway design; Sight distances; Geographic Information Systems; Terrain models; Global Positioning System

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ANALYSIS OF THE TEMPERATURE INFLUENCE ON FLEXIBLE PAVEMENT DEFLECTION

ANALYSIS OF THE TEMPERATURE INFLUENCE ON FLEXIBLE PAVEMENT DEFLECTION. Ramos, J.A., Castro, M. Construction and Building Materials 25 (8), 3530-3539. 2011.

Abstract

In this research, the effect produced by a temperature change on a flexible pavement deflection is analysed. Deflection tests were carried out on a road at different temperatures. The equipment used to measure pavement deflections was a curviameter. Based on the results of this experimental study, a methodology was established to define the experimental pavement temperature adjustment factors for deflection. In addition, the pavement structure studied was modelled, by means of a multilayer system, to calculate the deflections that would be produced below the load application point and, next, calculating the corresponding theoretical pavement temperature adjustment factors for deflection. Finally, the results obtained from the experimental study, theoretical analysis and main existing models are compared. The statistical analysis performed shows a good agreement between the experimental and theoretical obtained factors.

Highlights

► We study the influence of the asphalt mix temperatures on a flexible pavement.
► We obtain experimental adjustment factors by pavement temperature for deflection.
► We establish a methodology to calculate experimental factors, using curviameter.
► We define a new methodology to obtain theoretical adjustment factors.
► We perform a statistical analysis among obtained factors and main existing models.

Keywords: Deflection; Pavement temperature; Young modulus; Flexible pavement; Curviameter; Multilayer study

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OPERATING SPEED AND SPEED DIFFERENTIAL FOR HIGHWAY DESIGN CONSISTENCY

OPERATING SPEED AND SPEED DIFFERENTIAL FOR HIGHWAY DESIGN CONSISTENCY. Castro, M., Sánchez, J. F., Sánchez, J. A., Iglesias, L. Journal of Transportation Engineering, 137 (11), 837-840. 2011.

Abstract
A critical factor in highway design is maintaining a good consistency with a road geometry that fits the drivers’ expectations. Presently, highway geometric design consistency is usually evaluated on the basis of operating-speed profile analysis, which requires the use of operating-speed models. This paper presents research carried out in Colombia consisting of a study of vehicle speeds on tangents and curves of two-lane rural highways. Car speeds were measured on the approach tangent and at the beginning, middle, and end points of curves by using two radar meters. The operating-speed prediction models that were developed are described. The speed change experienced by drivers from tangent to curve was also studied, and a model is presented that predicts this change. Finally, the model developed for operating-speed prediction at the midpoint of curves was compared with equivalent models calibrated in other countries and applied to a Colombian highway. This comparative study highlights the importance of using speed-prediction models calibrated according to local conditions.

Keywords: Traffic speed; Highway and road design; Traffic safety; Models

http://vulcano.caminos.upm.es/