VEHICLE SPEED MEASUREMENT: COSINE ERROR CORRECTION

VEHICLE SPEED MEASUREMENT: COSINE ERROR CORRECTION. M. Castro, L. Iglesias, J. A. Sánchez. Measurement, 45 (8), 2128-2134. 2012.

Abstract

Although laser devices are commonly used to measure distances and vehicle speed in traffic safety-related studies, they suffer from a drawback known as the cosine effect. Furthermore, such traffic safety studies analyze both vehicle speed and a large amount of geographical data. As such, the development of efficient and cost-effective techniques for correcting the cosine error and managing the data involved in vehicle speed studies are needed. This paper presents an algorithm for correcting cosine error based on a Geographic Information System (GIS) that makes use of vehicle speed measurements and Global Positioning System (GPS) coordinates. An experiment using more than 350 vehicle speeds was conducted to test the algorithm, and the case study shows that controlling the quality of laser-measured speeds in order to suppress low quality data or correct measurement errors due to the cosine effect is very useful.

Highlights

► Laser devices are used to measure vehicle distance and speed in road studies.
► An algorithm, based on GIS, for correcting cosine error is presented.
► GIS use helps to manage data involved in vehicle speed studies.
► An experiment using more than 350 vehicles was conducted to test the algorithm.
► A discussion about laser location and measurement uncertainty is included.
 

Keywords

Laser; Speed models; Cosine error; Highway design; Consistency; Global Positioning System (GPS); Geographic Information System (GIS)


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

OPERATING SPEED MODELS FOR TWO-LANE RURAL HIGHWAYS

OPERATING SPEED MODELS FOR TWO-LANE RURAL HIGHWAYS. Castro, M., Sanchez, J. F., Sanchez, J. A. Proceedings of the Institution of Civil Engineers-Transport,  165 (2), 107-118. 2012.

Abstract

Drivers adapt their driving to the conditions that they find. When the design corresponds to what a driver hopes to find, the route is consistent. This diminishes the likelihood of drivers making errors and carrying out uncertain manoeuvres. Most evaluations of highway geometric design consistency are based on the analysis of vehicles' speeds. This study reviewed the main models of operating speed prediction on two-lane rural highways. Models calibrated in several countries have been compared by means of their application to the study of nine highway sections located in different terrain types. Also, field measurements have been included in the comparison. The research results show the strengths and weaknesses of those models, their similarities, differences and the lack of suitability of some of them for mountainous highways. Based on them, specific recommendations about which models would be suitable for use are included. The speed profiles predicted by the Spanish model show, in general, higher values than most models calibrated in other countries.

Keywords:  mathematical modelling; roads & highways; traffic engineering


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