01004377

Component

The results of two field studies carried out to measure vision angles from both rear-view mirrors and to obtain dimensions of the most popular sold cars are presented. Finally, the influence of the available lateral visibility of vehicles in the geometric design of merging points and skewed intersections is evaluated, and the maximum safety angles for merging and skewed intersections are proposed. A minimum direct field of vision of 220 degrees is assumed. From this hypothesis, and from a design vehicle based on measurements taken during the field study, a skewed intersection that offers an adequate intersection sight distance was analyzed. The experimental part of the study consisted of designing a device able to measure vision angles from rear-view mirrors, and using it on a sample of 174 cars. From this data, weighted according to the sales and the proportion of sales per year on the total number of vehicles in Spain, the design angles of lateral visibility were determined. As design vision angles from the rear-view mirrors, 10th percentiles were employed, and a correct seating position was used. At the same time, the best selling car dealers were visited to measure any related dimensions. A design vehicle was adopted weighting adequate dimensions. From these design angles and the dimensions of the mentioned design vehicle, a model was proposed for merging, in such a way that no vehicle could be placed in the driver's blind spot. Thus, the maximum angle between merging lane and the main road was obtained, for safe maneuverings. In a right skewed intersection, with a vehicle about to cross the intersection, in accordance with the dimensions of the design vehicle, the driver's direct field of vision and the intersection angle, the cases in which there is sufficient intersection sight distance are evaluated. In left skewed intersections, the recommendations given by previous research must prevail, since it is more restrictive for vehicles with lateral opaque bodyworks.

01004374

English

23p

2005

3rd International Symposium on Highway Geometric Design

CD-ROM

Figures (9) ; Photos (1) ; References (24) ; Tables (3)

Field of vision; Field studies; Geometric design; Intersections; Merging traffic; Rearview mirrors; Sight distance

Design vehicles; Lateral vision angles; Skewed intersections

Design; Highways; I20: Design and Planning of Transport Infrastructure

TRIS, TRB, ATRI

Sep 22 2005 2:46PM