ISO 16785:2026

• Abstract:

  This document specifies requirements for an application interface between dedicated short-range communication on-board equipment (DSRC-OBE) and external in-vehicle devices to make DSRC-OBE applicable for diversified electronic fee collection (EFC) systems. This document applies to: — definitions of the application interface between DSRC-OBE and external in-vehicle devices; — definitions of data groups and data elements.

• Status: Published
• Publication Date: 18-Aug-2026
• ICS: 03.220.20 - Road transport
• ICS: 35.240.60 - IT applications in transport
• Technical Committee: ISO/TC 204 - Intelligent transport systems
• Drafting Committee: ISO/TC 204/WG 5 - Fee and toll collection
• Current Stage: 6060 - International Standard published
• Start Date: 19-Aug-2026
• Due Date: 31-Oct-2026
• Completion Date: 19-Aug-2026

• Revises: ISO/TS 16785:2020 - Electronic Fee Collection (EFC) — Application interface definition between DSRC-OBE and external in-vehicle devices
• Effective Date: 04-Nov-2023

Overview

ISO 16785:2026 defines standardized requirements for the application interface between dedicated short-range communication on-board equipment (DSRC-OBE) and external in-vehicle devices within electronic fee collection (EFC) systems. This standard addresses the growing need for interoperability as road tolling evolves to support expanded services, diverse payment models, and integration with advanced in-vehicle functionalities like global navigation satellite systems (GNSS) and cellular networks. By specifying how DSRC-OBE communicates with various external devices, ISO 16785:2026 enables seamless fee collection across autonomous and DSRC-based tolling infrastructures, ensuring adaptability and future-proofing for rapidly evolving intelligent transportation systems (ITS).

Key Topics

• Interface Definitions: Specifies the logical application interface between DSRC-OBE and external in-vehicle devices, ensuring harmonized data exchange for EFC operations.
• Data Groups and Elements: Defines structures and contents of data exchanged, including payment status, account updates, payment fees, compliance attributes, and localization data.
• Diversified Tolling Models: Supports interoperable EFC environments that combine DSRC-based and autonomous toll systems across varied infrastructure types and regions.
• Conformance Requirements: Outlines procedures and proformas for confirming device compliance, supporting reliable and standardized implementation.
• Security Considerations: Recommends secure data exchange methodologies, including entity authentication and data encryption, to safeguard EFC operations.
• Applicable DSRC Standards: Designed for global compatibility with major DSRC standards (CEN, UNI, ARIB, TTA, GB), supporting broad deployment.

Applications

ISO 16785:2026 delivers practical value for a wide range of stakeholders in the EFC ecosystem:

• Toll Service Providers: Facilitates integration of DSRC-OBE with external modules, enabling value-added services, expanded toll road coverage, and real-time account management via GNSS and cellular links.
• Automotive OEMs and Device Manufacturers: Reduces development complexity by providing clear definitions for in-car device interfaces and data protocols, ensuring compatibility and simplified upgrades.
• Transport Authorities: Supports implementation of diversified tolling regimes-including distance-based, time-based, and event-based charging-helping authorities transition to modern road user charging models.
• System Integrators: Enables scalable, modular deployments with standardized APDU (application protocol data unit) exchanges, enhancing system interoperability and maintainability.
• User Experience Enhancement: Through reliable status updates and secure payment operations, road users benefit from transparent, seamless toll transactions regardless of infrastructure environment.

Common use cases include upgrades of existing DSRC-based systems to autonomous tolling, integration of new payment methods, and implementation of sophisticated compliance checking mechanisms-ensuring ISO 16785:2026’s relevance for current and future smart mobility initiatives.

Related Standards

For comprehensive EFC system integration and advanced functionality, ISO 16785:2026 references and aligns with several international standards:

• ISO 12813 – Electronic fee collection - Compliance check communication for autonomous systems
• ISO 12855 – Electronic fee collection - Information exchange between service provision and toll charging
• ISO 13141 – Electronic fee collection - Localization augmentation communication for autonomous systems
• ISO 15628 – Intelligent transport systems - Dedicated short range communication (DSRC) - Application layer
• ISO 17573-2 – Electronic fee collection - System architecture for vehicle-related tolling - Vocabulary
• ISO 17573-3 – Electronic fee collection - Data dictionary for vehicle-related tolling
• ISO/IEC 8825-2 – ASN.1 encoding rules
• ISO/IEC 9798-4 – Entity authentication protocols

These standards form the foundation for secure, interoperable, and future-ready electronic toll collection systems worldwide, reinforcing the role of ISO 16785:2026 as a key enabler for advanced and adaptable EFC interfaces.

International
Standard
ISO 16785
First edition
Electronic fee collection —
2026-08
Application interface definition
between dedicated short-range
communication on-board
equipment (DSRC-OBE) and
external in-vehicle devices
Perception de télépéage — Définition de l'interface entre
l'équipement de bord à communications dédiées à courte portée
(DSRC-OBE) et des dispositifs externes embarqués
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms. 2
5 Tolling models with the in-vehicle devices . 3
5.1 General .3
5.2 Tolling model .3
5.2.1 Operating environment .3
5.2.2 Data exchanges .5
5.2.3 Application protocol data units.6
5.3 Conformance .9
5.3.1 Conformance requirements .9
5.3.2 Conformance statement .9
6 ADUs descriptions . 10
6.1 General .10
6.2 PaymentMeansStatus ADU data structure .10
6.2.1 General .10
6.2.2 PaymentMode .10
6.3 AccountUpdate ADU data structure .11
6.3.1 General .11
6.3.2 ReloadAccount .11
6.3.3 NewAccountLimit . 12
6.3.4 AddToAccount . 12
6.3.5 AuthenticatedReloadAccount . 13
6.3.6 AuthenticatedNewAccountLimit . 13
6.3.7 AuthenticatedAddToAccount . 13
7 Security aspects .13
7.1 General . 13
7.2 OBE interface profile . 13
Annex A (normative) Data type specification.15
Annex B (normative) Protocol implementation conformance statement proforma .16
Annex C (informative) Clarification of data elements .20
Bibliography .22

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
This first edition cancels and replaces the second edition (ISO/TS 16785:2020), which has been technically
revised.
The main changes are as follows:
— Clause 3 has been updated and ISO 17573-2 has been made the primary source for terms and definitions;
— addition of information regarding the application data units (ADUs) for information exchange between
dedicated short-range communication on-board equipment (DSRC-OBE) (see Clause 6);
— modification of information regarding the external in-vehicle device (see 5.2.1);
— modification of the ASN.1 code; see Annex A and attached ASN.1 file;
— revision of data elements related to compliance checking communication imported from ISO 12813 (see
5.2.3);
— deletion of the charge report and reference to ISO 17575-1.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
0.1  Background and motivation
For sustainable road environment, the road tolling policy in different regions of the world has spread
from conventional road tolling, such as funding for road infrastructure management and maintenance,
environmental measures, and traffic management, to other aspects. Specifically, to accommodate the
widespread use of low-fuel-consumption and electric vehicles, introduction of road user charging instead of
fuel tax, congestion tolling on urban roads and inter-urban roads is planned and implemented.
In the countries where dedicated short-range communication (DSRC) based electronic fee collection (EFC)
systems are widely deployed, upgrading and extension of the schemes, to include roads that are currently
not tolled become a significant issue to consider.
This document describes how DSRC-based EFC systems, especially on-board equipment (OBE), can be
enhanced to meet these needs.
There are three cases of introducing EFC systems to cope with these situations:
— Case-1: An existing DSRC-based EFC system is extended and introduced on new roads.
— Case-2: An autonomous EFC system is introduced on both new roads and the existing toll roads.
— Case-3: A DSRC-based EFC system continues to operate on existing toll roads, and an autonomous EFC
system is introduced on new toll roads.
For Case-1 and Case-2, the interface definitions and the test procedures are defined by existing EFC
standards. For Case-3 as shown in Figure 1, the OBE used for DSRC-based EFC can also be used for the
autonomous EFC system covering new roads and existing toll roads.
A DSRC-OBE can be applied in new EFC environments consisting of DSRC-based EFC and the autonomous
EFC system by expanding its functionality by interfacing with the external in-vehicle devices that includes
a global navigation satellite system (GNSS) module, cellular network communication (CN) module and other
related modules.
Consequently, an application interface definition between DSRC-OBE and the external in-vehicle devices is
described in this document.
Figure 1 — Image of expanding toll roads and services (Case-3)

v
0.2  Purpose of this document
The purpose of this document is to provide support for enhanced functionalities of DSRC-OBE by means of
external in-vehicle devices.
This document intends to define:
— a tolling model with the external in-vehicle devices (see in subclause 5.2);
— data groups and data elements (see Clauses 5 and 6);
— data types and the protocol implementation conformance statement (PICS) proforma (in Annexes A
and B).
0.3  Applicable dedicated short-range communication on-board equipment (DSRC-OBE)
There are five major DSRC standards currently being deployed for EFC around the world: CEN-DSRC, UNI-
DSRC, ARIB-DSRC, TTA-DSRC and GB-DSRC. In standardizing an application interface between DSRC-OBE
and an external in-vehicle devices, the interface should be applied for every type of DSRC as shown in
Figure 2.
Figure 2 — Applicable DSRC-OBE
Due to its operational reliability, DSRC-OBE is suitable for EFC. On the other hand, each component of
an external in-vehicle devices typically has a shorter product life than DSRC-OBE to meet changing user
demands for multi-functional and high-performance components.
Once an application interface has been standardized, DSRC-OBE can be used seamlessly in a variety of EFC
environments with an enhanced new external in-vehicle devices as shown in Figure 3.
Figure 3 — Applicability for future upgrading

vi
International Standard ISO 16785:2026(en)
Electronic fee collection — Application interface definition
between dedicated short-range communication on-board
equipment (DSRC-OBE) and external in-vehicle devices
1 Scope
This document specifies requirements for an application interface between dedicated short-range
communication on-board equipment (DSRC-OBE) and external in-vehicle devices to make DSRC-OBE
applicable for diversified electronic fee collection (EFC) systems.
This document applies to:
— definitions of the application interface between DSRC-OBE and external in-vehicle devices;
— definitions of data groups and data elements.
The scope of this document is illustrated in Figure 4:
Figure 4 — Scope of this document
This document is not applicable to:
— definitions of hardware components in the external in-vehicle devices such as GNSS receiver, CN mobile
device;
— definitions of the physical interface between DSRC-OBE and the external in-vehicle devices;
— definition of value-added services (VAS);
— definition of algorithms for authentication, encryption and key management for security aspect.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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/IEC 8825-2, Information technology — ASN.1 encoding rules — Part 2: Specification of Packed Encoding
Rules (PER)
ISO 12813, Electronic fee collection — Compliance check communication for autonomous systems
ISO 12855, Electronic fee collection — Information exchange between service provision and toll charging
ISO 13141, Electronic fee collection — Localization augmentation communication for autonomous systems
ISO 15628:2013, Intelligent transport systems — Dedicated short range communication (DSRC) — DSRC
application layer
ISO 17573-2, Electronic fee collection — System architecture for vehicle related tolling — Part 2: Vocabulary
ISO 17573-3, Electronic fee collection — System architecture for vehicle-related tolling — Part 3: Data dictionary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17573-2 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols and abbreviated terms
ADU application data unit
APDU application protocol data unit
ARIB Association of Radio Industries and Businesses
NOTE 1 ARIB is a communication standardization organization in Japan.
ASN.1 abstract syntax notation one
CAN controller area network
CCC compliance check communication
CN cellular network
DSRC dedicated short-range communication
EFC electronic fee collection
GB Guojia Biaozhun
NOTE 2 GB is a national standard published by Standardization Administration of China.
GNSS global navigation satellite system
HMI human-machine interface
IUT implementation under test
LAC localization augmentation communication
OBE on-board equipment
OBD on-board diagnostics
OBU on-board unit
PICS protocol implementation conformance statement
RSE roadside equipment
TC toll charger
TSP toll service provider
TTA Telecommunications Technology Association
NOTE 3 TTA is a communication standardizing body in the Republic of Korea.
UNI Ente Nazionale Italiano di Unificazione
NOTE 4 UNI is a communication standardizing body in Italy.
URL uniform resource locator
VAS value added services
5 Tolling models with the in-vehicle devices
5.1 General
The DSRC-OBE with the external in-vehicle devices can support various EFC environments and further VAS
as shown in Figure 1.
There are two kinds of settlement method in EFC, one is the on-board account system, and the other method
is the central account system. In the case of on-board account system, payment means may be connected
to DSRC-OBE as shown in Figure 5, and the toll amount determined by the tolling transaction processes
is directly deducted from payment means in the case of pre-payment. In the case of post payment system,
the toll amount is posted to the central system with a personal account number transmitted from payment
means.
Figure 5 — Arrangement of payment means
5.2 Tolling model
5.2.1 Operating environment
The system in which DSRC-OBE is connected to the external in-vehicle devices should support the diversified
tolling system that supports both the autonomous EFC system and DSRC-based EFC system as shown in
Figure 6. In the figure, RSE(L), RSE(C) and RSE(T) are equipment to communicate with DSRC-OBE via DSRC
communication. RSE(L) is used for localization checking by toll charger (TC) to verify the existence of the

vehicle in the serviced area. RSE(C) is used for compliance checking done by TC to verity the validity of
OBE via DSRC communication. The information can be exchanged through these transactions with the toll
service provider (TSP) via the external in-vehicle device.
NOTE RSE(T) is used for DSRC tolling by TC, no relation with the external in-vehicle device.
Key
RSE(L) RSE for localization augmentation via DSRC communication
RSE(C) RSE for compliance checking via DSRC communication
RSE(T) RSE for tolling via DSRC communication
Figure 6 — Tolling model for the diversified tolling
In the diversified tolling system, the external in-vehicle devices consist of the various components listed in
Table 1.
Table 1 — Configurations for tolling system
Tolling system DSRC-OBE Major components of the external in-vehicle devices
GNSS re- CN mobile HMI Motion Interfaces to vehicle
ceiver device sensors
Digital CAN
tachograph (OBD-II)
DSRC-based EFC m — — — — — —
Autonomous tolling m m m o o o o
m: mandatory, o: option, —: not applicable

As a minimum configuration, the external in-vehicle devices should include GNSS receiver and CN mobile
device. The following components should be considered as optional parts for implementation that depends
on the requirements of autonomous EFC system:
a) HMI;
b) motion sensors;
c) digital tachograph interface;
d) controller area network’s on-board diagnostics (CAN, OBD-II) interface.
The external in-vehicle devices shall connect to the back end of the TSP to exchange the required autonomous
EFC related data through cellular networks. DSRC-OBE shall be connected with individual RSE that exchange
the related data for DSRC tolling, compliance check and localization through DSRC.
Whereas Figure 6 shows the configuration in which the external in-vehicle devices and DSRC-OBE are
physically separated, these can be integrated into a single OBE device.
5.2.2 Data exchanges
Figure 7 shows the general data exchanges between the external in-vehicle devices and the DSRC-OBE. As
shown in the figure, external in-vehicle devices and the DSRC-OBE transfer the following information:
— information exchanged between TSP (back end) and DSRC-OBE, e.g. charge report, charge report
response, context data and context data response;
— information exchanged between DSRC-OBE as a processing result done by TC and the external in-vehicle
devices, e.g. payment means status, account update, payment fee, compliance check communication
(CCC) and localization augmentation communication (LAC) data.
For the communications, this document defines data interface between the external in-vehicle devices and
DSRC-OBE.
The relationship of the data groups in the entire EFC system is explained in Annex C.

Key
RSE(L) RSE for localization augmentation via DSRC communication
RSE(C) RSE for compliance checking via DSR communication
RSE(T) RSE for tolling via DSRC communication
Figure 7 — Data exchanges for the diversified tolling
5.2.3 Application protocol data units
Between the DSRC-OBE and the external in-vehicle devices, information exchanges are performed by means
of APDU transfers.
The structure of the APDU is shown in Figure 8.

Figure 8 — Structure of APDU (InfoExchangeObe)
The ASN.1 data type that shall be used can be found via the URL in Annex A.
The APDU is specified as ASN.1 data type InfoExchangeObe, which is described in Table 2.
Table 2 — Data elements of InfoExchangeObe
Data element Data type/data description Status
infoExchangeObeContent
InfoExchangeObeContent (see Table 3). m
This data element shall contain the actual content of the
APDU.
infoExchangeAuthenticator
Data type is AuthenticatorEfc. Record (ASN.1 SEQUENCE) o
made of three fields of types tbsAuthenticatorEfc,
signatureAlgorithm and signatureValue.
This data element may optionally contain an authen-
ticator calculated over the content of data element
infoExchangeContent
m: mandatory, o: option, —: not applicable
The mandatory data type InfoExchangeContent is described in Table 3.
Table 3 — Data elements of InfoExchangeObeContent
Data element Data type/data descri
...