SIST-TP CEN/TR 15762:2009

Road transport and traffic telematics - Electronic fee collection (EFC) - Ensuring the correct function of EFC equipment installed behind metallised windshield

Metallised windscreens are produced by spraying small metal particles on one of the glass or plastic layers of the vehicle’s windscreen. This leads to a windscreen with high thermal qualities, ranging from far-reduced power consumption by air-conditioning equipment to short times for de-icing.
The production of certain vehicles in Europe which were equipped with metallised windscreens has created a major problem for the installation and operation of On-Board Units (OBUs) which rely on Dedicated Short-Range Communications (DSRC) for ITS (as the most-widely deployed DSRC ITS application to date, the remainder of this report will refer to Electronic Toll Collection (EFC) but the developed solutions will be valid for all DSRC ITS applications). As is shown in Table 1, windscreen properties have a decisive influence on the transmission of microwave communication and, for metallised windows, it is essential to compensate these losses by special measures (Ref 1).

Straßenverkehrstelematik - Elektrische Gebührenerhebung (EFC) - Sicherstellung der korrekten Funktion bei Installation der On-board-Units hinter metallisch bedampften Windschutzscheiben

Télématique des transports - Perception électronique des péages routiers - Fonctionnement des badges en présence de pare-brise athermiques

Les pare-brise athermiques sont réalisés en projetant de petites particules métalliques sur l’une des couches de verre ou de plastique du pare-brise du véhicule. Cela donne un pare-brise ayant de grandes qualités thermiques, permettant une forte réduction de la consommation d’énergie grâce à l’air conditionné et un raccourcissement de la durée de dégivrage.
La production en Europe de certains véhicules équipés de pare-brise athermiques a créé un grave problème pour l’installation et le fonctionnement des dispositifs embarqués qui reposent sur des communications dédiées à courte portée pour les systèmes de transport intelligents (le reste de ce rapport portera sur la perception électronique des péages routiers, car c’est, à l’heure actuelle, l’application la plus répandue des systèmes de transport intelligents de communication, mais les solutions développées seront valables pour toutes les applications des systèmes de transport intelligents de communication). Comme le montre le Tableau 1, les propriétés du pare-brise ont une incidence déterminante sur la transmission des communications par micro-ondes et, pour les vitrages athermiques, il est indispensable de compenser ces pertes en prenant des dispositions particulières (Réf. 1).
Tableau 1 — Pertes de transmission du verre de sécurité à une fréquence de 5,8 GHz (Réf. 1)
Type de verre   Pertes de transmission en passage direct
verre de 3,5 mm   2 .. 4 dB
verre feuilleté de sécurité de 5 mm   2 .. 5 dB
verre feuilleté de sécurité à fil chauffant   5 .. 7 dB
verre feuilleté de sécurité métallisé de 4 mm   20 .. 40 dB
Des voitures équipées de vitrages athermiques étant livrées en grand nombre depuis juillet 1997, il est nécessaire de traiter ce problème.
Il est important de noter que la solution proposée est valable pour les voitures particulières mais pas pour les véhicules à pare-brise quasiment vertical comme les camions et les bus.

Cestna transportna in prometna telematika - Elektronsko pobiranje pristojbin (EFC) - Zagotavljanje pravilnega delovanja opreme za elektronsko pobiranje pristojbin (EFC), nameščene za vetrobranskim steklom s kovinsko prevleko

General Information

• Status: Published
• Publication Date: 04-Mar-2009
• ICS: 35.240.60 - IT applications in transport
• ICS: 43.040.15 - Car informatics. On board computer systems
• Technical Committee: ITC - Information technology
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 03-Mar-2009
• Due Date: 08-May-2009
• Completion Date: 05-Mar-2009
• Mandate: M/338 - Standardisation mandate to CEN, CENELEC and ETSI in support of interoperabilty of electonic road toll systems in the community
• Ref Project: CEN/TR 15762:2008 - Road transport and traffic telematics - Electronic fee collection (EFC) - Ensuring the correct function of EFC equipment installed behind metallised windshield

Overview

CEN/TR 15762:2008 addresses how to ensure reliable Electronic Fee Collection (EFC) and other DSRC-based ITS services when On-Board Units (OBUs) are installed behind metallised windscreens. Metallised windscreens - glass or plastic layers sprayed with metal particles to improve thermal performance - can cause significant microwave attenuation at the DSRC test frequency (5.8 GHz), jeopardising tolling and short-range communications. The technical report defines practical mitigation: a dedicated non-metallised communication window in the windscreen and design/installation constraints to restore dependable radio performance.

Key topics and requirements

• Impact on RF transmission
  • Typical single-pass transmission losses at 5.8 GHz: non-metallised glass ~2–5 dB (depending on type); metal-coated/ metallised windscreens can cause much higher losses (on the order of tens of dB) and require compensation.
• Recommended non-metallised window solution (manufacture-time mask or laser)
  • Lateral placement: centred on the windscreen to support both left- and right-hand traffic markets.
  • Maximum lateral tolerance: 80 mm from the windscreen lateral centre.
  • Minimum window size: 120 mm wide × 70 mm high.
  • Minimum distance to vehicle body (edge): 110 mm.
  • Minimum installation volume behind window: 125 mm wide × 83 mm high × 34 mm deep (to accommodate OBU and antenna clearance).
• Applicability limits
  • Solution is intended for passenger cars (not near-vertical windscreens of trucks or buses).
  • Short-term validity for non-heated communication windows of normal thickness (≈5 mm).
• Regulatory and safety constraints
  • Must respect vehicle glazing, driver field-of-view, rear-view mirror and interior impact safety regulations (e.g., ECE-R43, EU driver field-of-view directives).

Applications and who uses it

• Vehicle manufacturers (OEMs): windscreen design and production to include EFC-compatible zones.
• OBU/tag designers and suppliers: product sizing, antenna placement and installation templates.
• Toll operators and ITS integrators: ensure interoperability and roadside coverage with DSRC EFC systems.
• Test laboratories and compliance engineers: verify RF performance and installation compliance.
• Standards bodies and policymakers: harmonise vehicle/telecommunications requirements across Europe.

Related standards

Relevant CEN/TC 278 documents for EFC and DSRC referenced in the report include:

• EN 12253 (physical layer at 5.8 GHz)
• EN 12795 (data link layer)
• EN 12834 (application layer)
• EN 13372 (profiles)
• CEN ISO/TS 14907-1 / -2 (test procedures)
• EN 15509 (interoperability application profile)

CEN/TR 15762:2008 is a practical guidance document for ensuring reliable DSRC/EFC operation in the presence of metallised windscreens and supports interoperable, Europe-wide tolling and ITS deployments. Keywords: CEN/TR 15762:2008, metallised windscreens, electronic fee collection, EFC, DSRC, On-Board Unit, non-metallised window, 5.8 GHz.

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2009
&HVWQDWUDQVSRUWQDLQSURPHWQDWHOHPDWLND(OHNWURQVNRSRELUDQMHSULVWRMELQ
()&=DJRWDYOMDQMHSUDYLOQHJDGHORYDQMDRSUHPH]DHOHNWURQVNRSRELUDQMH
SULVWRMELQ()&QDPHãþHQH]DYHWUREUDQVNLPVWHNORPVNRYLQVNRSUHYOHNR
Road transport and traffic telematics - Electronic fee collection (EFC) - Ensuring the
correct function of EFC equipment installed behind metallised windshield
Straßenverkehrstelematik - Elektrische Gebührenerhebung (EFC) - Sicherstellung der
korrekten Funktion bei Installation der On-board-Units hinter metallisch bedampften
Windschutzscheiben
Télématique des transports - Perception électronique des péages routiers -
Fonctionnement des badges en présence de pare-brise athermiques
Ta slovenski standard je istoveten z: CEN/TR 15762:2008
ICS:
35.240.60 Uporabniške rešitve IT v IT applications in transport
transportu in trgovini and trade
43.040.15 $YWRPRELOVNDLQIRUPDWLND Car informatics. On board
9JUDMHQLUDþXQDOQLãNLVLVWHPL computer systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 15762
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
July 2008
ICS 35.240.60
English Version
Road transport and traffic telematics - Electronic fee collection
(EFC) - Ensuring the correct function of EFC equipment installed
behind metallised windshield
Télématique des transports - Perception électronique des Straßenverkehrstelematik - Elektrische Gebührenerhebung
péages routiers - Fonctionnement des badges en présence (EFC) - Sicherstellung der korrekten Funktion bei
de pare-brise athermiques Installation der On-board-Units hinter metallisch
bedampften Windschutzscheiben
This Technical Report was approved by CEN on 1 June 2008. It has been drawn up by the Technical Committee CEN/TC 278.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15762:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3
Introduction .4
1 Scope .4
2 Constraints .5
2.1 General.5
2.2 Regulations affecting vehicle design and installation of equipment.5
2.2.1 Introduction.5
2.2.2 Windscreen.5
2.2.3 Rear-view mirrors .5
2.2.4 Interior impact safety .5
2.2.5 Conclusions .6
2.3 European Standards related to EFC .6
2.3.1 Introduction.6
2.3.2 List of relevant CEN/TC 278 standards .6
3 Non-metallised window.7
3.1 General.7
3.2 Non-metallised window parameters .7
3.2.1 General.7
3.2.2 Values .7
3.2.3 Applicability of results .10

Foreword
This document CEN/TR 15762:2008 has been prepared by Technical Committee CEN/TC 278 “Road
transport and traffic telematics”, the secretariat of which is held by NEN.
Introduction
European car manufacturers are introducing metallised windscreens at a wide scale throughout Europe.
These windscreens have interesting thermal qualities but risk to compromise the correct functioning of On-
Board Units (OBUs) for Electronic Fee Collection (EFC) communicating with the roadside.
As it is essential to come to Europe-wide solutions, an ERTICO committee was created in February 1998 to
work toward consensus on a common solution. Overall, 25 organisations have actively followed the work of
this committee by attending the meetings and/or by contributing by (e-)mail. As a result the committee
proposed the use of a non-metallised window as a Europe-wide solution. This solution consists in providing a
zone in the windscreen that is free of metal coating. The ERTICO committee produced a document "Ensuring
th
the correct functioning of EFC equipment installed behind metallised windscreens". During the 37 TC 278
meeting CEN/TC 278 adopted the resolution 037/05/2006 to publish this document as a Technical report.
1 Scope
Metallised windscreens are produced by spraying small metal particles on one of the glass or plastic layers of
the vehicle’s windscreen. This leads to a windscreen with high thermal qualities, ranging from far-reduced
power consumption by air-conditioning equipment to short times for de-icing.
The production of certain vehicles in Europe which were equipped with metallised windscreens has created a
major problem for the installation and operation of On-Board Units (OBUs) which rely on Dedicated Short-
Range Communications (DSRC) for ITS (as the most-widely deployed DSRC ITS application to date, the
remainder of this report will refer to Electronic Toll Collection (EFC) but the developed solutions will be valid
for all DSRC ITS applications). As is shown in Table 1, windscreen properties have a decisive influence on the
transmission of microwave communication and, for metallised windows, it is essential to compensate these
losses by special measures (Ref 1).
Table 1 — Transmission losses of safety glass at a frequency of 5.8 GHz (Ref 1)
Glass type Single-pass transmission losses
glass 3.5 mm 2 . 4 dB
laminated safety glass 5 mm 2 . 5 dB
laminated safety glass with heating wire 5 . 7 dB
20 . 40 dB
laminated safety glass metal-coated 4O/

As cars equipped with metallised windows are being shipped in large numbers since July 1997, this problem
needs to be addressed.
It is important to note that the solution proposed is valid for passenger cars and not for vehicles with near-to-
vertical windscreens such as trucks and buses.
2 Constraints
2.1 General
There are three types of constraints that need to be considered when investigating possible solutions for EFC
OBU problems created by metallised windscreens:
 constraints imposed by regulations affecting vehicle design and installation of equipment;
 constraints imposed by European Standards related to EFC;
 constraints imposed by the current market situation.
2.2 Regulations affecting vehicle design and installation of equipment
2.2.1 Introduction
A number of regulations that need to be observed by the design of the windscreen affect the location of the
OBU within the vehicle. Important in this respect are the so-called A-zone and B-zone of the windscreen, two
safety-critical sub-divisions of the windscreen in which transmission of light and optical distortion are subject to
constraints.
Below, the main regulations affecting the installation of EFC tags are summarised.
2.2.2 Windscreen
 ECE-R43 (and all amendments): uniform regulations for the approval of
...