Study on the alignment of individual objects that can cause sight obstruction during dynamic control of tramway systems
Management: STRMTG/DTMR
Production: Grouping of several service providers (see end of article) January 2021 - ongoing
Good visibility is a key factor in safety, enabling tramway drivers to anticipate potentially accident-prone situations, such as the risk of collision with another motorist (or pedestrian, cyclist, etc.), and to adapt their driving accordingly.
In 2018, STRMTG and Cerema co-developed a reference guide to ensure minimum visibility when approaching intersections, in the form of IUTCS sheet no. 04 - Tramway and visibility: methods and tools (accompanied by its spreadsheet tool).
This method, based on the determination of "visual safety" zones or visibility cones, has been used in particular for imposing sight obstructions or continuous, opaque sight obstructions.
However, this data sheet does not provide guidance on the case of aligned and repeated obstacles (poles, barriers, openwork fences, etc.), which do not constitute a significant barrier to visibility when static, but which could nevertheless become one when aligned and during dynamic driving. Visual obstructions can form a kind of wall (see photo examples below) depending on the characteristics of the interaction with the tramway (speed, angle of approach, etc.), and this effect is yet to be studied.
Example of an alignment of barriers with vertical rails that can create a visual obstruction in a dynamic situation
Example of a line of objects (trees + catenary poles) that can obstruct visibility in a dynamic situation
To provide some solutions to the problem of individual objects and visibility, STRMTG launched a public tender in 2021 for a study on the alignment of individual objects that can create a sight obstruction in dynamic tramway systems, in order to determine the impact of a succession of individual objects that can form a sight obstruction along a moving tram approaching an intersection.
The aim of this study is to determine the impact of a succession of individual objects on the approach to an intersection, and then to define the determining factors that play a role in the transition of the evaluated objects from visibility to sight obstruction.
For the study, an experimental campaign involving professional tramway drivers was necessary. A number of experimental tools have been used, including a driving simulator and an eye-tracking system (equipment that provides information on the direction of the driver’s gaze while driving).
The tender was awarded to a three-member consortium made up of:
A transport research laboratory (LAMIH), a joint multi-disciplinary laboratory between CNRS and Université Polytechnique Hauts-de-France;
A company specialising in human factors analysis (FactHum France);
A company specialising in railway simulation (OKTAL).
The study should be completed in 2023.
Article written by the STRMTG Department for Trams and Rolling Stock (DTMR).