Electronic fee collection - Charging performance - Part 1: Metrics (ISO/TS 17444-1:2012)

This part of ISO/TS 17444 defines metrics for the charging performance of electronic fee collection (EFC) systems in terms of the level of errors associated with charging computation. This part of ISO/TS 17444 is a toolbox standard of metrics. The detailed choice of metrics depends on the application and the respective context. This part of ISO/TS 17444 describes a set of metrics with appropriate definitions, principles and formulations, which together make up a reference framework for the establishment of requirements for EFC systems and their later examination of the charging performance. The charging performance metrics defined in this part of ISO/TS 17444 are intended for use with any Charging Scheme, regardless of its technical underpinnings, system architecture, tariff structure, geographical coverage, or organizational model. They are defined to treat technical details that may be different among technologies and vendors or vary over time as a “black box”. They focus solely on the outcome of the charging process - i.e. the amount charged in relation to a premeasured or theoretically correct amount - rather than intermediate variables from various components as sensors, such as positioning accuracy, signal range, or optical resolution. This approach ensures comparable results for each metric in all relevant situations. The metrics are designed to cover the information exchanged on the Front End interface and the interoperability interfaces between Toll Service Providers, Toll Chargers and Road Users as well as on the End-to-End level. Metrics on the following information exchanges are defined: - Charge Reports; - Toll Declarations; - Billing Details and associated event data; - Payment Claims on the level of user accounts; - User Accounts; - End-to-End metrics which assess the overall performance of the charging process. The details on the rationale of this choice are described in 5.1. The proposed metrics are specifically addressed to protect the interests of the actors in a toll system, such as Toll Service Providers, Toll Chargers and Road Users. The metrics can be used to define requirements (e.g. for requests for proposals) and for performance assessment. This part of ISO/TS 17444 recognizes two types of situations where a performance assessment is necessary: a) when an assessment is carried out during a limited time span, such as when formulating requirements and assessing systems for acquisition purposes, conducting acceptance testing as part of the commissioning process, or as part of a certification procedure. Any one of these types of assessment is referred to as an evaluation; b) when an assessment is needed as an ongoing supervision process, throughout the lifetime of a system, in order to validate contracted service levels, to identify fraud or malfunction, or to support ongoing maintenance and performance improvement processes. This type of assessment is referred to as monitoring. The following are not covered by this part of ISO/TS 17444. - This part of ISO/TS 17444 does not propose specific numeric performance bounds, or average or worstcase error bounds in percentage or monetary units.

Elektronische Gebührenerhebung - Abbuchungsdurchführung - Teil 1: Metriken (ISO/TS 17444-1:2012)

Perception du télépéage - Performance de charge - Partie 1: Mesurages (ISO/TS 17444-1:2012)

Elektronsko pobiranje pristojbin - Uspešnost zaračunavanja - 1. del: Meritve (ISO/TS 17444-1:2012)

Ta del standarda ISO/TS 17444 določa meritve za uspešnost zaračunavanja sistemov za elektronsko pobiranje pristojbin (EFC) na podlagi ravni napak, povezanih z izračuni zaračunavanja. Ta del standarda ISO/TS 17444 je osnovni standard meritev. Podrobna izbira meritev je odvisna od uporabe in povezanega konteksta. Ta del standarda ISO/TS 17444 opisuje sklop meritev z ustreznimi opredelitvami, načeli in ubeseditvami, ki skupaj sestavljajo referenčni okvir za določitev zahtev za sisteme za elektronsko pobiranje pristojbin ter poznejši pregled njihove uspešnosti zaračunavanja. Meritve uspešnosti zaračunavanja iz tega dela standarda ISO/TS 17444 so namenjene uporabi v zvezi s katerim koli sistemom zaračunavanja, ne glede na njegovo tehnično zasnovo, sistemsko arhitekturo, tarifno strukturo, geografsko pokritost ali organizacijski model. Določijo se za obravnavanje tehničnih podrobnosti, ki se lahko razlikujejo med tehnologijami in ponudniki ali se sčasoma spreminjajo kot »črna skrinjica«. Osredotočajo se izključno na rezultat postopka zaračunavanja, tj. na znesek, ki se zaračuna glede na vnaprej izmerjen ali teoretično pravilen znesek, in ne na vmesne spremenljivke, ki izhajajo iz različnih sestavnih delov senzorjev, kot je položajna natančnost, doseg signala ali optična ločljivost. Ta pristop zagotavlja primerljive rezultate za vsako meritev v vseh ustreznih primerih. Meritve so namenjene obravnavanju informacij, izmenjanih v okviru čelnega vmesnika in vmesnikov interoperabilnosti med izvajalci storitev cestninjenja, pobiralci cestnine in uporabniki cest ter tudi na celostni ravni. Opredeljene so meritve v zvezi z naslednjimi izmenjavami informacij: – poročila o zaračunavanju, – izjave o plačilu cestnine, – podatki o plačilu in povezani podatki o dogodku, – zahtevki za plačilo na ravni uporabniških računov, – uporabniški računi, – celotne meritve, ki ocenijo splošno delovanje postopka zaračunavanja. Podrobnosti o utemeljitvi te izbire so navedene v točki 5.1. Predlagane meritve so posebej namenjene zaščiti interesov udeležencev v sistemu cestninjenja, kot so izvajalci storitev cestninjenja, pobiralci cestnine in uporabniki cest. Meritve je mogoče uporabiti za opredelitev zahtev (npr. za zahteve za predloge) in ocenjevanje uspešnosti. Ta del standarda ISO/TS 17444 priznava dve vrsti primerov, v katerih je potrebna ocena uspešnosti: a) kadar se ocena izvaja v omejenem časovnem obdobju, na primer pri oblikovanju zahtev in oceni sistemov za namene pridobivanja, izvajanju preskušanja ustreznosti v okviru postopka začetka obratovanja ali v okviru postopka certificiranja, pri čemer se vse te vrste ocene imenujejo vrednotenje, ter b) kadar je ocena potrebna v okviru stalnega nadzornega postopka v celotni življenjski dobi sistema, da se validirajo ravni pogodbene storitve, opredeli goljufija ali okvara ali podprejo stalni postopki vzdrževanja in izboljšave uspešnosti. Ta vrsta ocene se imenuje spremljanje. Naslednji elementi niso vključeni v ta del standarda ISO/TS 17444. – Ta del standarda ISO/TS 17444 ne predlaga posebnih številčnih omejitev uspešnosti ali omejitev povprečnih napak ali napak v najslabšem primeru v odstotkih ali denarnih enotah. O navedenem odloča pobiralec cestnine (ali sporazumi med pobiralcem cestnine in izvajalcem storitve), pri čemer se zagotavlja način, s katerim je mogoče zagotoviti skladno omrežje za opisovanje sistemskih zahtev pri pisanju zahtevka za predloge, sistemske primerjave med pridobivanjem, rezultate preskusov, sporazume na ravni storitve in trajno spremljanje uspešnosti (po uporabi). – Ta del standarda ISO/TS 17444 ne obravnava vrednotenja pričakovane uspešnosti sistema, ki temelji na modeliranju in izmerjenih podatkih, pridobljenih med poskusom ali iz drugega vira.

General Information

Status
Withdrawn
Publication Date
26-Dec-2012
Withdrawal Date
11-Dec-2017
Technical Committee
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
11-Dec-2017
Due Date
03-Jan-2018
Completion Date
12-Dec-2017

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SLOVENSKI STANDARD
SIST-TS CEN ISO/TS 17444-1:2013
01-januar-2013
(OHNWURQVNRSRELUDQMHSULVWRMELQ8VSHãQRVW]DUDþXQDYDQMDGHO0HULWYH
,6276

Electronic fee collection - Charging performance - Part 1: Metrics (ISO/TS 17444-1:2012)

Elektronische Gebührenerhebung - Abbuchungsdurchführung - Teil 1: Metriken (ISO/TS

17444-1:2012)

Perception du télépéage - Performance de charge - Partie 1: Mesurages (ISO/TS 17444-

1:2012)
Ta slovenski standard je istoveten z: CEN ISO/TS 17444-1:2012
ICS:
03.220.20 Cestni transport Road transport
35.240.60 Uporabniške rešitve IT v IT applications in transport
transportu in trgovini and trade
SIST-TS CEN ISO/TS 17444-1:2013 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN ISO/TS 17444-1:2013
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SIST-TS CEN ISO/TS 17444-1:2013
TECHNICAL SPECIFICATION
CEN ISO/TS 17444-1
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
October 2012
ICS 03.220.20; 35.240.60
English Version
Electronic fee collection - Charging performance - Part 1:
Metrics (ISO/TS 17444-1:2012)

Perception du télépéage - Performance d'imputation - Elektronische Gebührenerhebung -

Partie 1: Métrique (ISO/TS 17444-1:2012) Abbuchungsdurchführung - Teil 1: Metriken (ISO/TS 17444-

1:2012)

This Technical Specification (CEN/TS) was approved by CEN on 30 September 2012 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their

comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available

promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)

until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United

Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 17444-1:2012: E

worldwide for CEN national Members.
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SIST-TS CEN ISO/TS 17444-1:2013
CEN ISO/TS 17444-1:2012 (E)
Contents Page

Foreword ..............................................................................................................................................................3

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SIST-TS CEN ISO/TS 17444-1:2013
CEN ISO/TS 17444-1:2012 (E)
Foreword

This document (CEN ISO/TS 17444-1:2012) has been prepared by Technical Committee CEN/TC 278 “Road

transport and traffic telematics", the secretariat of which is held by NEN, in collaboration with Technical

Committee ISO/TC 204 "Intelligent transport systems".

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,

Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,

Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

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SIST-TS CEN ISO/TS 17444-1:2013
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SIST-TS CEN ISO/TS 17444-1:2013
TECHNICAL ISO/TS
SPECIFICATION 17444-1
First edition
2012-10-01
Electronic fee collection — Charging
performance —
Part 1:
Metrics
Perception du télépéage — Performance d’imputation —
Partie 1: Métrique
Reference number
ISO/TS 17444-1:2012(E)
ISO 2012
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SIST-TS CEN ISO/TS 17444-1:2013
ISO/TS 17444-1:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s

member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST-TS CEN ISO/TS 17444-1:2013
ISO/TS 17444-1:2012(E)
Contents Page

Foreword ............................................................................................................................................................................iv

Introduction ........................................................................................................................................................................ v

1 Scope ...................................................................................................................................................................... 1

2 Normative references ......................................................................................................................................... 2

3 Terms and definitions ......................................................................................................................................... 3

4 Abbreviated terms ............................................................................................................................................... 7

5 Definition of charging performance metrics ................................................................................................ 7

5.1 General ................................................................................................................................................................... 7

5.2 Metric Identification .......................................................................................................................................... 11

5.3 End-to-End metrics ........................................................................................................................................... 11

5.4 User Account Metrics .......................................................................................................................................12

5.5 Payment Claim Metrics ....................................................................................................................................13

5.6 Billing Details Metrics ......................................................................................................................................13

5.7 Toll Declaration Metrics ...................................................................................................................................15

5.8 Charge Report Metrics .....................................................................................................................................18

Annex A (informative) Defining Performance Requirements ................................................................................21

Bibliography .....................................................................................................................................................................24

© ISO 2012 – All rights reserved iii
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SIST-TS CEN ISO/TS 17444-1:2013
ISO/TS 17444-1:2012(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International

Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

In other circumstances, particularly when there is an urgent market requirement for such documents, a technical

committee may decide to publish other types of document:

— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in

an ISO working group and is accepted for publication if it is approved by more than 50 % of the members

of the parent committee casting a vote;

— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical

committee and is accepted for publication if it is approved by 2/3 of the members of the committee

casting a vote.

An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further

three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed,

it is reviewed again after a further three years, at which time it must either be transformed into an International

Standard or be withdrawn.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO/TS 17444-1 was prepared by Technical Committee ISO/TC 204, Intelligent transport systems, and by

Technical Committee CEN/TC 278, Road transport and traffic telematics in collaboration.

ISO 17444 consists of the following parts, under the general title Electronic fee collection — Charging performance:

— Part 1: Metrics [Technical Specification]
— Part 2: Examination framework
1) To be published.
iv © ISO 2012 – All rights reserved
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ISO/TS 17444-1:2012(E)
Introduction

Electronic Tolling systems are complex distributed systems involving critical technology such as dedicated

short-range communication (DSRC) and global navigation satellite systems (GNSS) both subject to a certain

random behaviour that may affect the computation of the charges. Thus, in order to protect the interests of the

different involved stakeholders, in particular Service Users and Toll Chargers, it is essential to define metrics

that measure the performance of the system as far as computation of charges is concerned and ensure that

the potential resulting errors in terms of size and probability are acceptable. These metrics will be an essential

tool when establishing requirements for the systems and also for examination of the system capabilities both

during acceptance and during the operational life of the system.

In addition, in order to ensure the interoperability of different systems it will be necessary to agree on common

metrics to be used and on the actual values that define the required acceptable performances, although this is

not covered in this part of ISO/TS 17444.

Toll schemes take on various forms as identified in ISO/TS 17575 (all parts) and ISO 14906. In order to create

a uniform performance metric specification, toll schemes are grouped into two classes, based on the character

of their primary charging variable: Charging based on discrete events (charges when a vehicle crosses or

stands within a certain zone), and those based on a continuous measurement (duration or distance).

The following are examples of discrete (event-based) toll schemes.

— Single object charging: a road section, bypass, bridge, tunnel, mountain pass or even a ferry, charged per

passage; most tolled bridges belong to this category.

— Closed road charging: a fixed amount is charged for a certain combination of entry and exit on a motorway

or other closed road network; many of the motorways in Southern Europe belong to this category.

— Discrete road links charging: determined by usage of specified road links, whether or not used in their entirety.

EXAMPLE German heavy goods vehicle (HGV) charge.

— Charging for cordon crossing: triggered by passing in or out through a cordon that encircles a city

core, for example.
EXAMPLE Stockholm congestion charging.
The following are examples of continuous toll schemes.

— Charging based on direct distance measurement: defined as an amount per kilometre driven.

EXAMPLE Switzerland’s HGV charge; US basic vehicle miles travelled approach.

— Charging based on direct distance measurement in different tariff zones or road types: defined as an

amount per kilometre driven, with different tariffs applying in different zones or on different road types. This

is a widely discussed approach, also known as Time-Distance-Place charging, and is under consideration

in many European countries. The pilot programme in Oregon is an example from North America.

— Time in use charge: determined by the accumulated time a vehicle has been in operation, or, alternatively,

by the time the vehicle has been present inside a predefined zone.

In all these examples of toll schemes, tolls may additionally vary as a function of vehicle class characteristics

such as trailer presence, number of axles, taxation class, operating function, and depending on time of day or

day of week, so that, for example, tariffs are higher in rush hour and lower on the weekends.

With this degree of complexity, it is not surprising to find that the attempts to evaluate and compare technical

solutions for Service User charging have been made on an individual basis each time a procurement or study

is initiated, and with only limited ability to reuse prior comparisons made by other testing entities.

The identification of different types of schemes as proposed in ISO/TS 17575 (all parts) and their grouping in

the mentioned two classes is described in Table 1, which also identifies the examples mentioned above.

© ISO 2012 – All rights reserved v
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SIST-TS CEN ISO/TS 17444-1:2013
ISO/TS 17444-1:2012(E)
Table 1 — Tolling scheme designs grouped according to Scheme categories
Examples Scheme type ISO/TS 17575 category
Single object charging Discrete Sectioned roads pricing
Closed road charging Discrete Sectioned roads pricing
Discrete road links charging Discrete Sectioned roads pricing
Charging for cordon crossing Discrete Cordon pricing
Time in use charge Continuous Area pricing – time
Cumulative distance charge Continuous Area pricing – distance

Charging for cumulative distance (or time) in different zones Continuous Area pricing – distance

(or by road type)

No toll schemes are purely continuous. At the very least, a system must be able to stop accumulating charges

when it leaves a jurisdiction in which a charge is due, and resume charging when it returns or enters another.

Additionally, many Charging Schemes are set up so that the tariff is modified using discrete parameters, such

as spatial zones, time spans, vehicle classes, etc. Under those circumstances, each unit of distance or time

costs a different amount depending, for example, on whether it takes place inside or outside an area, such as

a city, whether a trip takes place in rush hour or at night, or depending on what type of vehicle is used. In this

part of ISO/TS 17444 references to a “continuous system” have to be understood as those systems having

some continuous behaviour even though they may also integrate some discrete nature. References to “discrete

systems” are limited to those systems that are purely discrete.

In these schemes, all the discrete parts (zones, cordons, events, time, vehicle class, etc.) that a system has

to identify are translated into a particular tariff (e.g. price per kilometre) that has to be applied to the measured

continuous variable (e.g. travelled kilometres) resulting in another continuous parameter, money.

Among the different Interoperability Application Profiles defined in CEN/TS 16331, only Section Road Tolling

has a purely discrete nature while the other four profiles have both discrete and continuous natures.

Some features of discrete and continuous toll schemes that are of relevance for the definition of metrics

proposed in this part of ISO/TS 17444 are analysed below.
Discrete toll schemes

In a discrete toll scheme, distinct events are associated with the identification of Charge Objects. It can be

that a vehicle crossed a cordon, passed a bridge, was present in an area, or in an area on a given day. An

event that takes place can either be correctly recorded by the system or can be missed. However, there is also

the possibility that an event is recorded even though it did not actually take place. This is summarized in the

following matrix in Table 2.
Table 2 — Theoretical event decision matrix for discrete schemes
System detects Chargeable Event
Event Matrix
Yes No
Missed Recognition
Correct
Yes
Charging
(Undercharging)
Chargeable Event takes
place
False Positive
Correct
Non-charging
(Overcharging)

In this matrix there are two successful scenarios (Correct Charging and Correct Non-charging), and two

unsuccessful (Missed Recognition and False Positive). The unsuccessful scenarios have very different

consequences. A Missed Recognition, i.e. a Chargeable Event that takes place but is not recorded by the

system, implies an undercharging, as the Service User is not charged.
vi © ISO 2012 – All rights reserved
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ISO/TS 17444-1:2012(E)

In the case of False Positive, a vehicle that is not using the toll domain is being charged for an event which did

not take place. This implies an overcharging which is in violation of the legal rights of the Service User, and

ultimately risks eroding trust in the system.

This part of ISO/TS 17444 therefore makes a distinction between the two types of errors and defines associated

metrics to protect the interests of the Toll Charger and Service Users in terms of the allowed probabilities of

those events.
Continuous toll schemes

A continuous toll scheme is one where the charge is calculated using accumulated time or distance the base

tariff is applied to.

Note that a discrete scheme with a large number of Charge Objects would lead to charging incremental

variations, and is hence approaching a continuous scheme (the higher the number of events, the closer such

schemes are to a continuous scheme). In any case, this would still formally be a discrete scheme.

In discrete toll schemes errors are binary: either a Charge Event is correctly recorded or it is not. However, in

continuous schemes the errors are relatively small and they vary continuously, i.e. those errors are real (in the

mathematical sense) variables instead of logical variables. Figure 1 shows different levels of dispersion and

different directions of bias. The horizontal axis shows the size of the errors and the vertical axis the probability

density. The vertical line in each plot represents zero charging error. Note that it is possible to have small

dispersion (i.e. a small standard deviation) that still biases charging high or low (i.e. not accurate).

Charging Error Charging Error
Charging Error Charging Error
Figure 1 — Idealized plots of error distribution of four different result sets

In Figure 1 Chart A symbolizes the results from a Front End with more dispersion than that used for Chart B.

For all parties involved, B is preferable to A. Charts C and D show two Front Ends with the same standard

deviation, but where Chart C shows one that is consistently undercharging, and D one that is consistently

overcharging road usage.
© ISO 2012 – All rights reserved vii
Probability
Probability
Probability Probability
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ISO/TS 17444-1:2012(E)

By defining an Accepted Charging Error Interval to the chart, with a lower and an upper bound, as shown in

Figure 2, it is possible to state that for a system to be accepted it must perform so that some minimum share of

the measurements fall inside the interval specified as accepted by the Toll Charger.

Accepted Error Interval
Charging Error
Figure 2 — Definition of Accepted Error Interval

Setting the upper and lower bounds far apart relaxes requirements on the equipment evaluated, while setting

them closer together would make the requirement to fulfil harder to pass. By setting the upper bound closer to

the correct charging value and the lower bound farther away, the Toll Charger can formalize exactly how much

more important it is to avoid overcharging than it is to avoid undercharging. By defining those bounds (Accepted

Charging Error Interval) together with the probabilities to be inside and above those bounds the Toll Charger can

define precisely its requirements distinguishing between overcharging and undercharging. In reality no scheme

is purely continuous and all foreseeable continuous schemes have some discrete components. The discrete

nature of real systems can be either associated to the physical border of a country (continuous measurements

take place only if vehicle is within the country) or to the identification of different urban zones or roads where

different tariffs (per unit of time or distance) are applied.

Thus, continuous schemes will have associated metrics that are specific to those continuous systems but the

ones identified for discrete schemes will also be applicable.
viii © ISO 2012 – All rights reserved
Probability Density
Lower Bound
Correct Charging
Upper Bound
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SIST-TS CEN ISO/TS 17444-1:2013
TECHNICAL SPECIFICATION ISO/TS 17444-1:2012(E)
Electronic fee collection — Charging performance —
Part 1: Metrics
1 Scope

This part of ISO/TS 17444 defines metrics for the charging performance of electronic fee collection (EFC)

systems in terms of the level of errors associated with charging computation.

This part of ISO/TS 17444 is a toolbox standard of metrics. The detailed choice of metrics depends on the

application and the respective context.

This part of ISO/TS 17444 describes a set of metrics with appropriate definitions, principles and formulations,

which together make up a reference framework for the establishment of requirements for EFC systems and

their later examination of the charging performance.

The charging performance metrics defined in this part of ISO/TS 17444 are intended for use with any Charging

Scheme, regardless of its technical underpinnings, system architecture, tariff structure, geographical coverage,

or organizational model. They are defined to treat technical details that may be different among technologies

and vendors or vary over time as a “black box”.

They focus solely on the outcome of the charging process – i.e. the amount charged in relation to a pre-

measured or theoretically correct amount – rather than intermediate variables from various components as

sensors, such as positioning accuracy, signal range, or optical resolution. This approach ensures comparable

results for each metric in all relevant situations.

The metrics are designed to cover the information exchanged on the Front End interface and the interoperability

interfaces between Toll Service Providers, Toll Chargers and Road Users as well as on the End-to-End level.

Metrics on the following information exchanges are defined:
— Charge Reports;
— Toll Declarations;
— Billing Details and associated event data;
— Payment Claims on the level of user accounts;
— User Accounts;

— End-to-End metrics which assess the overall performance of the charging process.

The details on the rationale of this choice are described in 5.1.

The proposed metrics are specifically addressed to protect the interests of the actors in a toll system, such as

Toll Service Providers, Toll Chargers and Road Users. The metrics can be used to define requirements (e.g.

for requests for proposals) and for performance assessment.

This part of ISO/TS 17444 recognizes two types of situations where a performance assessment is necessary:

a) when an assessment is carried out during a limited time span, such as when formulating requirements and

assessing systems for acquisition purposes, conducting acceptance testing as part of the commissioning

process, or as part of a certification procedure. Any one of these types of assessment is referred to as

an evaluation;
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b) when an assessment is needed as an ongoing supervision process, throughout the lifetime of a system, in

order to validate contracted service levels, to identify fraud or malfunction, or to support ongoing maintenance

and performance improvement processes. This type of assessment is referred to as monitoring.

NOTE 1 Definitions and metrics proposed in this part of ISO/TS 17444 are intended for both situations.

The following are not covered by this part of ISO/TS 17444.

— This part of ISO/TS 17444 does not propose specific numeric performance bounds, or average or worst-

case error bounds in percentage or monetary units. Those decisions are left to the Toll Charger (or to

agreements between Toll Charger and Service Provider), while providing a way to be sure that there

is a consistent framework for describing system requirements when writing Request for proposals, for

system comparisons during acquisition, for test results, for Service Level Agreements, and ongoing (post-

deployment) performance monitoring.

— This part of ISO/TS 17444 does not consider the evaluation of the expected performance of a system

based on modelling and measured data from trial at another place.

— This part of ISO/TS 17444 does not consider the specification of a common reference system which would

be required for comparison of performance between systems.

— This part of ISO/TS 17444 does not specify metrics on parts of tolling systems other than the charging

process chain, such as:
— enforcement system;
— security measures.

— This part of ISO/TS 17444 does not cover metrics on parts of the charging processing chain which are

considered an internal matter of one of the interoperability partners:

— equipment performance, e.g. for on-board equipment, road-side equipment or data centres such as

signal range, optical resolution or computing system availability;

— position performance metrics: The quality of data generated by position sensors is considered as an

internal aspect of the Front End. It is masked by correction algorithms, filtering, inferring of data and

the robustness of the Charge Object recognition algorithms.

Even though some of these aspects have a direct impact on charging performance, they are not considered

explicitly in this part of ISO/TS 17444.

NOTE 2 While the Front End interface is considered as internal to the Toll Service Provider domain of responsibility,

it is still covered by metrics. There are two reasons for this exception: firstly a set of standards [ISO/TS 17575 (all parts)]

exists on this interface and secondly the information exchanged on this interface is also part on the TSP-TC interface

(ISO 12855) and therefore metrics are needed.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced document

(including any amendments) applies.

ISO 14906, Electronic fee collection ― Application interface definition for dedicated short-range communication

ISO 17573, Electronic fee collection ― Systems architecture for vehicle-related tolling

ISO 12855, Electronic fee collection ― Information exchange between service provision and toll charging

ISO/TS 17575-1, Electronic fee collection ― Application interface definition for autonomous systems ―

Part 1: Charging
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3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
Absolute Charging Error

difference between the measured charge (toll) value and the actual value (as measured by a reference system)

NOTE A positive error means that the measur
...

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