Luis Iglesias

GIS-Based System for Sight Distance Analysis of Highways

Analyzing the distance visible to a driver on a highway is important for traffic safety, especially in manoeuvres such as emergency stops, when passing another vehicle, or when vehicles cross at intersections. Software that calculates highway distances visible to a driver has been developed. This software is supported by a geographic information system (GIS) and can use a trajectory defined by points obtained with a global navigation satellite system (GNSS) receiver instead of relying on project information. The software includes specific tools for studying shortcomings in three-dimensional (3D) alignment; mainly, this pertains to divings. In this article, the software and its application to a case study are presented. The results are compared with those obtained using an existing validated procedure.

Operating speed and speed differential for highway design consistency

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.

A nonlinear mixed model for the assessment of traffic noise levels in urban areas

Quantification of traffic noise levels in urban areas can be especially useful for environmental and public health policies. A statistical model is proposed here for this quantification in small urban areas. The model is nonlinear and mixed, with two components: a fixed component for traffic noise emission (source effect) and a random component for assessing traffic noise propagation. The proposed model requires only sample data and has been used to estimate basic noise indicators established in European standards. A composite indicator, the Lden indicator, has been computed and used to draw up a noise ranking of urban areas. The proposed approach is applied to the city of Leganés (Spain).

Co-integration of acoustic simulation software and GIS for speech intelligibility analysis in complex multi-source acoustic environments. Application to Toledo's Cathedral

The speech intelligibility in complex multi-source acoustic environments depends on a variety of factors such as speech level, background noise level, reverberation time, as well as psychoacoustic effects. Since these factors can change for each source-receiver combination, in order to integrate information from various sources, efficient tools and techniques are required to determine the speech intelligibility at every listener position. In drawing up this study, two types of tools are used: (i) an acoustic simulation software (ODEON) and (ii) spatial analysis tools of a Geographic Information System (ArcGIS). To determine the speech intelligibility, the Speech Transmission Index (STI) has been calculated. Sound Pressure Level and Reverberation Time have been calculated at points of a grid at intervals of 1 meter. An automated workflow using ArcGis Modelbuilder has been created in order to obtain STI. Also, Arcmap has been used to represent and analyze the results over the complex geometry of the space. ...