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Contents

1. Radio in the Car and the User Experience

2. Hybrid Radio and the Connected Car

3. Consumer Use Cases

4. Visual Design Guidelines

5. Emergency Alerts and Warnings

6. Performance of DAB+

Annex

Annex A - Detailed design & Operation Considerations

Annex B - Example Visuals

Annex C - NABA UX Guidelines: Comparison Table

Annex D - Glossary of terms

Annex E - Local Legislation

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1. The Group – Radio in the Car and the User Experience

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1.2 Background: WorldDAB in-car User Experience Group

The WorldDAB in-car user experience group was formed in 2016 to:

Improve the user interface for in-car digital radio putting the consumer at the heart of the design process
Understand how future technology will impact on UI design plus improve & innovate within the UI
Identify & action collaboration between broadcasters and car manufacturers Produce collaborative broadcast/car manufacturer user interface design guidelines

The Group represents an unprecedented collaboration between broadcasters, leading car manufacturers and in-car technology providers. The Group holds four meetings per year at which the UX Guidelines are reviewed and updated.

WorldDAB has produced a set of UX guidelines for automotive manufacturers and broadcasters on how to deliver the best possible digital radio user experience. These guidelines were informed by research - read more about that research here.

WorldDAB also publishes important research into listening in the car. The “Dashboard Dialogue” released in 2023 was a major survey of recent & prospective car buyers conducted by Edison Research for WorldDAB, conducted across France, Germany and the UK, through in-car interviews with radio listeners, and over 2,400 online interviews. “91% of recent and prospective car buyers said it was important that their recent or next vehicle has DAB/DAB+ or FM radio”, reinforcing the value of radio to the driver.

To find out more about WorldDAB Auto initiatives contact: rosemary.smith@worlddab.org

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1.3 Background: Document status

This is the public version of the UX guidelines now called the “Design Guidelines for DAB+ Digital Radio / In-car User Experience Guidelines” incorporating feedback received from car manufacturers and includes:

Specific updates to the current version include:

The radio state should be preserved between "ignition off" and "ignition on"
The service list navigation should always be positioned at the current station / last listened station
The service list should be ordered according to Unicode UCA for the current locale - ordered as alphabetical, then numerical, then punctuation characters
Requirement to better explain how functions like "Service Following" will work for the driver
Dealing with very long service lists

This document is live and is subject to change as and when feedback is received from stakeholders and partners.
The current focus of the WorldDAB UX Group is to continue engagement with OEMs to help support the UX design, good DAB+ performance
The North American Broadcasters Association (NABA) has produced a set of UX Guidelines based on the 4th version (Jan 2022 - v.37) of this document - differences between the NABA and World DAB documents are summarized in Annex C

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2. Hybrid Radio and the Connected Car

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2.1 A Hybrid Radio Future in the Connected Car

Radio is evolving in-line with increased connectivity in the car and the introduction of voice

The WorldDAB UX Group believes that Hybrid radio with DAB, DAB+ as the core and FM and IP working together provides the best radio experience in next generation connected cars by making the best use of the relative strengths of each platform

Broadcast radio: Free-to-air, robust, good coverage
IP: Metadata, return path, interactivity

Hybrid radio is already available in some new cars and on the roadmap for many more. See Section 5 of these guidelines for guidance on implementing hybrid radio.

It is evident that a good hybrid radio implementation enables car manufacturers to meet almost all the UX guidelines and can provide the best possible digital radio UX for drivers.

See EBU study on the cost-benefit analysis of FM, DAB, DAB+ and IP: https://tech.ebu.ch/publications/tr_2017_radio

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3. Consumer Use Cases

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3. Consumer Use Cases

Informed by the research and discussion within the UX group, a number of consumer use-cases have been identified. If delivered together, they form an easy to use UI and provide a structure for the design guidelines:

Consumers indicated that “I want”….

to find the radio function (including DAB+) easily in the car media system

to find radio stations (including DAB+ stations) easily

the list of stations to be up to date

to be able to easily set a station as a pre-set

to keep listening to my station if it’s available

to know more about what I’m listening to

my DAB+ radio to be set up for me

to easily use the radio whilst driving*

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3.1 Finding broadcast radio in the media system

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3.1 Guideline: Finding broadcast radio in the media system

Design guidelines:

Include a permanent “Radio” button on the dashboard or the top-level menu on the screen.
Selecting “Radio” should default to a harmonised (FM/DAB+ etc.) service list, or where individual systems are presented separately, to DAB+
In a hybrid radio the best platform signal will be automatically selected
When listening to AM/FM, include a “DAB+” button on the screen
Where there is no “Radio” button: Selecting a radio station is only 2 clicks from the home screen
Provide a mechanism for no more than “2 click” switching between a projection system (e.g., Apple CarPlay, Android Auto) and car radio.
Radio should turn on automatically at the last state / station when the vehicle "ignition" is "turned on" - even if the radio functionality is implemented as an "app".
Radio service list should be positioned at the currently / most recently tuned station

Hardware/ technical reference:

No DAB+ technical reference included in this section as relates to UX design by vehicle manufacturers.

Consumers want:

In cars without a “Radio” button on the dashboard or screen, most consumers find it frustrating and difficult to find the radio function quickly, reducing ease of use. Research shows that cars with a “Radio” button provide this solution.

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3.1.2 Wireframe Example: Finding broadcast radio in the media system

Home

Radio

Media

Nav

Phone

Radio button on the top level permanent menu on-screen

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3.2 DAB+ station search

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3.2 Guideline: DAB+ station search

Consumers want:

A quick, easy and safe way to search for and find their DAB+ stations that does not require knowledge of the DAB+ broadcast network. Research shows that an A-Z station list provides this.

Design guidelines:

Present an integrated and unified A-Z list of all available stations (FM, DAB, DAB+, IP). If this is not possible then the list defaults to DAB+ or present an A-Z list of all available DAB+ stations
Optional: It may also be useful to offer an A-Z list of alphabetic characters where consumers can choose the first letter of their wanted station and be presented with all available stations starting with that letter. A numerical “1” can be shown before “A” to denote stations that start with a number
Note: Most users will not use ensemble information or channel codes, and don’t understand them, if they are shown within the station list

Hardware /technical requirements:

Note: Delivering a dynamic, accurate A-Z station list requires dual DAB+ tuners
SPI via DAB+ or RadioDNS (https://radiodns.org/) can help create a single station listing

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3.2 Wireframe Example: DAB+ station search

Alphabetical ‘Jump’ list, takes you to all stations whose name begins with that letter. Stations beginning with a number may be shown first. Optional to show a numerical “1” in the scrolling list before “A”

Assumes touch-screen scrolling is available. Physical scrolling wheel/button also available for search

Home

Radio

Media

Nav

Phone

Service Label

Logo

A-Z station list of available stations. Dynamic updates made upon starting the car and then as new stations become available and existing stations are lost. Service logos are optional and can be either square / rectangle

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3.3 Radio Station Lists

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3.3 Guideline: Radio Station Lists

Consumers want:

Their list of radio stations to include all available DAB+ stations, be current and dynamically updated for a richer experience.

Design guidelines:

The station list should be automatically updated when stations become available or unavailable
Part-time stations should be displayed with an appropriate indication if they are not currently available
The driver should however have the choice to turn this feature off
Note: Pre-sets should remain even if service is currently unavailable
For connected cars that provide a list of stations based upon vehicle location, the receiver must combine any additional stations that are currently receivable from broadcast
Duplicate versions of the same service should only be added to the list once

Hardware/technical references

Delivering a dynamic, accurate A-Z station list requires dual DAB+ tuners
ETSI TS 103 176 section 6 describes how to keep service lists updated with new, removed and part-time services

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3.3 Wireframe Example: Radio station lists

Home

Radio

Media

Nav

Phone

Service Label

Logo

A-Z station list of available stations. A-Z, numeric, punctuation order. Ignore case sensitivity of alphabetical characters.

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3.4 Setting radio pre-sets

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3.4 Guideline: Setting radio presets

Consumers want:

To be able to set station presets as it makes using the radio easier. The action to set presets to be consistent across all radio platforms and radios (at home and in the car).

Design guidelines:

The action to set a radio preset should always be to press and hold a button when listening to the wanted station. Recommend 5 seconds hold to set and less than 1 second response time when tapping to select.
If the media system has physical numbered buttons, these should be used to press and hold when listening to the wanted station.
If the media system has touch-screen soft keys, these should be numbered or clearly marked as pre-set buttons.
Ensure clear instructions in the user manual for setting presets
Optional: If possible, on-screen prompts describing how to set a preset (until a pre-set has been set and therefore is understood)
Optional: Audible feedback to confirm the pre-set has been saved

Hardware/technical references:

No DAB+ technical reference included in this section as relates to UX design by vehicle manufacturers.

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3.4 Wireframe Example: Setting radio presets

When listening to the station press and hold the preset button, this will confirm the pre-set. Once set, it is preferable to show the station label

Home

Radio

Media

Nav

Phone

Service Label

Logo

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3.5 Continuity of station listening experience (Hardlinking / Softlinking)

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3.5 Consumer Case: Continuity of Station listening experience

Consumers want:

The radio to find the best signal (FM, DAB, DAB+ or IP) to ensure they can continue listening to their station.

Design guidelines:

For FM/DAB+ tuners, the radio should search for the best signal on FM, DAB, DAB-DAB, DAB-DAB+ for the station being listened to. This happens automatically.
If there is a delay in finding a station, display a message or have a dynamic icon (e.g. a spinner) to show an action is in progress
This function which is known technically as ‘Service Following/Linking” is turned ON in the car by default.
The driver is notified of ‘best signal search is on’ periodically so they understand if they don’t want it. This notification should also include guidance on how to turn it OFF
For FM/DAB+ tuners with IP access, the radio should search for the best signal on FM, DAB, DAB-DAB, DAB-DAB+, for the station being listened to. This happens automatically.

Hardware and technical references:

FM/DAB+ tuners including Implicit, Hard and Soft linking - ETSI 103 176; Digital Audio Broadcasting (DAB); Rules of implementation; Service information features.
FM/DAB/IP – Radio DNS https://radiodns.org/�

* Note: there is an option at importer level to turn off explicit Service Linking between DAB+ and FM as many non European countries will not have defined FM PI code systems and corresponding DAB+ SID codes for simulcast services.

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3.5 Wireframe Example: Continuity of Station listening experience

If there is a delay in finding the best signal, display a message or show an icon which indicates an action is in progress

Preset 1

Preset 2

Preset 3

Preset 4

Preset 5

Text or a "spinning wheel" icon is shown to indicate an action is in progress

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3.6 Information for drivers

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3.6 Consumer Case: Information for drivers

Consumers want:

Information about what they’re listening (e.g. station name, station logo, now playing, programme name) clearly presented on the screen. Broadcasters should be providing this information – both as text (Dynamic Labels, or DLS) and as images (Slideshow) to enhance the experience in the car.

Design guidelines:

Single-line text display – provide a button which shows the latest text message, scrolling if necessary to fit onto the display
Multi-line text display – always show the latest text message without the driver having to press any buttons
Colour screen display – always show the latest text message. Show the station logo until the first visual is received, then show it automatically. Logos in the station list should be sourced using RadioDNS lookup for SPI for connected vehicles, but acquisition of logos using SPI over DAB+ should also be supported.
Connected car – Request images at native screen resolution, for best quality

Hardware and technical references:

Dynamic Labels - ETSI EN 300 401v2.1.1
Slideshow (Visuals) - ETSI TS 101 499
Programme information and station logos (SPI) – ETSI TS 102 818
Radio DNS / WorldDAB guidance paper - Provision of Station Logos to Automotive Receivers https://www.worlddab.org/public_document/file/1091/StationLogosDoc_FINAL_2019.pdf?1548678132

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3.6 Wireframe Example: Information for drivers

Full Screen Image

Station Label

Station Identification

Preset 1

Preset 2

Preset 3

Preset 4

Preset 5

Optional: Pre-sets accessed from A-Z station list

Image�display or preview space

Text Information

Station Logo /�Visual Information

Touch to expand to full screen�

Connected car : request new image at new resolution if required

Station Logo

Traffic

Text information display, automatically updating

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3.6 Example – Station Information

Service Label

Where Programme Information (PI) is available, show a suitable icon

Home

Radio

Media

Recents

Favourite

Logo

Radio settings

Logo

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3.7 DAB+ automatic set up

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3.7 Guideline: DAB+ automatic set up

Consumers want:

Their default settings for the DAB+ radio to provide the best user experience. When consumers buy a new car, they are typically briefed by the dealer and unless it is specifically asked for, this briefing will not always include the DAB+ radio functionality and settings, DAB+ should therefore be factory set ON by default.

Design guidelines:

The following functions should all be on as default and form the basis of the factory reset status of the car media system:

Service following – DAB-FM-DAB+ / Hard linking / Soft linking*
A-Z station list (default option to search)
Automatic station list updating
Default to DAB and DAB+

Hardware and technical references:

Automatic station list updating requires dual tuners

*Note: There is an option at importer level to turn off explicit Service Linking between DAB+ and FM as many non-European countries will not have defined FM PI code systems and corresponding DAB+ SID codes for simulcast services.

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3.8 Voice control

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3.8 Consumer Case: DAB+ voice control

Consumer want:

To use their voice assistant to select a radio station to listen to, find out about the current station / programme / song that's playing, query the programme guide, get suggestions for other relevant stations and set / recall the station as a preset

Design Guidelines

Voice control, whether it be an OEM proprietary platform, Amazon Alexa, Google Assistant or others, lends itself perfectly to radio and significantly minimises driver distraction.
Voice assistants should be able to control broadcast DAB+ radio, as well as IP, via a hybrid radio implementation, working offline and online.
Voice assistants must also be able to provide accurate search results for all radio stations, recognising the phonetic detail of stations names and regional dialects.
When using voice control to access radio, the voice interface should follow the same priorities and listener preferences for signal source as the standard (non-voice) interface.
For services with a multilingual audience provide phonemes should be provided for each language.

Hardware and technical references:

Service & Programme Information – ETSI TS 102 818 v.3.51 (sections 5.14 / 5.15)

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3.9 Using hybrid DAB+ and IP in the connected car

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3.9 Hybrid Radio: Use Case

Hybrid radio: Enables car manufacturers to meet the majority of the UX Guidelines

Hybrid radio seamlessly combines Broadcast radio and the Internet. Your broadcast signal (FM, HD, DAB, DAB+) continues to carry audio (and some data), but a radio with an Internet connection (WiFi, 3G, 4G, LTE) can seamlessly connect back to your station for multimedia and interactivity.

In the car, Hybrid radios offers:

Service following - The ability to seamlessly switch between broadcast platforms and IP, following the strongest signal
High quality visuals - Station logos, artist information, news, weather and commercials
Interaction – Providing the listener with the ability to find out more about the content and offers the potential for greater personalisation

WorldDAB supports open standards for Hybrid radio and for more information go to https://radiodns.org/

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3.9 Hybrid Radio Guideline

Design Guidelines:

Station search should be presented in a single A-Z station list where stations are listed only once and the best platform with the strongest signal is automatically selected.

The radio should default to DAB+, then FM, then only move to IP streaming if the broadcast signals become unavailable. Once a broadcast signal becomes available again, the radio should switch back to either DAB+ or FM.

Seamless-switching (seamlessly blending the broadcast and IP streams to mitigate the inherent latency and ensuring the switch of platforms incurs no time delay) is recommended. Hard-switching (switching to another platform once the signal of the current platform becomes unavailable, with no attempt to mitigate the inherent latency between platforms) is possible but will provide a worse consumer experience with delays in switching between broadcast and IP.

Broadcaster supplied metadata should take precedence over metadata from other sources. Broadcaster supplied metadata provided over IP, where available, should be used in preference to that provided over DAB+. IP provided metadata is usually more comprehensive, faster to acquire and at a high detail / resolution.

Hardware and technical references:

https://radiodns.org for technical standards, questions and How To Guides

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3.9 Hybrid Radio: Resources

WorldDAB member companies that are experts in hybrid radio development:

AIM
Pluxbox
Radiobridge
Radioline
Radioplayer
Xperi

More information at https://www.worlddab.org/about/worlddab-members

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4. Visual Design Guidelines

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4.1 Ease of Use Considerations When Designing the DAB UX

UX design must take into account the risks of driver distraction

With more functionality on the screen in the car, digital radio stations sending information to this screen need some clear guidance on how to create visuals that ensure ease of use for the driver

Car manufacturers have also indicated that as visual images become a great feature in cars these images must remain legible, relevant & their update frequency must remain within agreed parameters

Four issues which must be considered when designing the DAB+ UX:

Legibility
Relevance
Frequency of Update
Familiarity of Use / Controls

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Legibility Relevance Update Familiarity� Frequency Of Use

If content isn't legible, the driver is distracted trying to understand it

Broadcasters - must design content for legibility and relevance

Manufacturers - must optimise the display of content for legibility

Establish mutual understanding of display environments

�

Irrelevant content causes unnecessary driver distraction

Broadcasters - must provide content that is unique and helpful to the driver.�(e.g. do not cycle through the station name and current date and time)

Manufacturers - must update content so it is legible without driver intervention�

Unfamiliar controls are difficult for the driver to use

Broadcasters - not applicable

Manufacturers - adopt established norms for user interactions for actions like tuning a station, setting a preset, changing volume

Updating content causes driver distraction

Broadcasters - must update content only when relevant and necessary, and not more frequently than every 20 seconds

Manufacturers - must update content so it is legible without driver intervention, but block updates that are sent more frequently than every 20 seconds

�

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4.2 Designing to maximise ease of use

Legibility is affected by physical rendering size

For each of the common components of a radio user interface, detailed guidance is given in Annex A on:

how to render the component for legibility (content, scaling, behaviour, physical size, prohibitions)
how to populate the component with metadata from the radio station
how a broadcaster should operate the functionality

The physical sizes are guidelines, and assume a physical screen size of 7" / 18cm diagonal, at 50-80cm from the driver's eyes.
These components can be assembled into any layout, allowing flexibility and innovation in user interface design

Maximising Available Screen Space

Some information is superfluous, and is rarely important to the end user. These should usually be omitted

Ensemble Name
Ensemble Frequency
DAB+ PTy (Programme Type)

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4.3 Designing to maximise ease of use

Use Driver Friendly Language to describe functionality

Try to avoid using technical language to describe functionality and user experience:
For example:

"Service Linking" becomes "Switch automatically to the best signal"
"News Announcements" becomes "Interrupt for news announcements"
"FM-DAB Linking" becomes "Use both DAB and FM for best signal"

Use icons that have established meaning

When creating new icons, establish the outcome of the action - if it can't be clearly expressed, consider using a labelled icon

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5. Emergency Alerts and Warnings

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5.1 Emergency Alerts and Warnings

Relaying important information to drivers

Emergency information for drivers is provided by

Announcements (type Alarm)
Automatic Safety Alert (ASA) systems

This information should be considered urgent and priority for the driver and should interrupt other sources
Announcements / ASA actions include audio and visual content; do not obstruct the visual space with dialogue boxes or similar
Any option for the driver to cancel the alert should not obstruct the visual content
You may provide an option for the driver to disable Announcement and ASA interruptions, but consider always providing a visual cue to the driver to switch to the announcement / warning even if audio / function interruption is disabled.

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6. Performance of DAB+ in-car

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6. Performance of DAB+ in-car

All the conditions are in place to offer great performance of DAB+ in-car:

DAB+ networks are maturing in many countries Broadcasters utilize the DAB+ capabilities: more and unique content, audio and visuals Latest DAB+ chips are lower cost with better performance and more features & functions

However, the challenge to get good in-car DAB+ reception is increasing, driven by: increased levels of radio interferences non-rooftop antenna systems with lower sensitivity. WorldDAB has conducted and collated research on antenna performance including highlighting the significant shortfalls performance of some antenna configurations and the substantial benefits offered by others

Car manufacturers have asked WorldDAB for DAB+ test routes in different markets to help development and performance measurement. WorldDAB has now published some DAB+ test routes in key European markets which can be found on the WorldDAB website: https://www.worlddab.org/automotive/dab-plus-test-routes

To ensure DAB+ performance enhances a great UX, dual DAB+ tuners and a good DAB+ antenna implementation are required
Example: See WorldDAB Aftermarket Device Guidelines for examples of good antenna placement which applies to vehicles as well as these devices - https://www.worlddab.org/automotive/aftermarket

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WorldDAB User Experience Research

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WorldDAB In-Car User Experience Research

This Group conducted the first ever qualitative consumer research on the DAB+ digital radio user interface in-car across five European markets: Germany, UK, France, The Netherlands and Belgium.

The research summary, full findings and consumer videos can be seen on the WorldDAB website: https://www.worlddab.org/automotive/user-experience-guidelines

The research has been used to inform these UX Guidelines, in particular the sections titled Consumer problems, Consumers want, and Consumer quotes

The headline findings of that research were:

Drivers expect a great, simple UX
A radio button is essential to access DAB+ easily and quickly
An A-Z station list is the best search UX
Pre-sets should be easy to set and the process must be consistent and explained
Terminology must be easier to understand

There was a high level of consistency in the consumer responses across geographic regions

The research was well received by the vehicle industry and several vehicle manufacturers have implemented the Guidelines

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A. Detailed Design &�Operation Considerations

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A.1 Design Considerations: Broadcasters

Designing Visuals for Quick and Easy Legibility (Slideshow)

"The entire image, including text, should be understandable with a 1 second glance"

When designing visuals, validate against the physical size and location of a typical display:

Usually about 50-80 cm from the driver's eyes, 7 inches / 18cm diagonal display size
Standard DAB+ resolution: 320px (W) by 240px (H), IP resolution : 640px (W) x 480px (H)
Smallest physical rendering of 70mm (vertical)

Text incorporated in visuals must be easily readable.

Guideline size of not less than 12% of the vertical height of the image
Proportionally spaced non-condensed characters
Don't use thin / lightweight characters
Check the screen in real life situations to ensure there is no text overflow

Variable resolution / responsive design considerations:

Some vehicles may request visuals in different resolutions / aspect ratios
Use HTML 5 / CSS 3 responsive design techniques to generate images on demand
Validate that responsive designs still meet the design requirements

Brightness and dazzle in darkness

At night, reduce the maximum brightness of visuals to 60%

*Approximations are used here due to variations between vehicle makes/models. Designing to these parameters will be appropriate for most vehicles

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A.1 Design Considerations: Broadcasters

Text Information (DLS)

"Convey useful information quickly"

When constructing text information, consider the display conditions

Don't duplicate information already visible on the display (station name, date, time)
Don't include information the driver can't use (station website address)
Not all the text may be visible immediately, and it may scroll slowly

General Content Considerations (for DLS Text and Visual Slideshow)

Consider what information the driver wants from a visual / text

Closely related to what they're listening to now
Gives further context or detail (e.g. information on the current song / advertisement)
Cycling and repetition of information is distracting (e.g. switching frequently between a station slogan and information about the current song)

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A.1 Design Considerations: Broadcasters

Station Logos

"Every station's logo is clearly identifiable in a list of radio stations"

Station Logos

Provide all the required image sizes
Only use PNG file format
Consider using cropped or stylised versions of your logo at the smaller resolutions, to maintain legibility, rather than simply re-scaling your logo

File formats and structures (Logos and Visuals)

Don't use transparency layers (on PNG), except on the external edges of irregularly shaped objects, as the background on which the PNG may be rendered is undefined - check compatibility with DARK and LIGHT modes
Produce JPG or PNG images in the correct formats (see TS 101 499 section 9.3)

these are often not the default file formats for popular image creation applications.

Special considerations for DAB+ Slideshow and DAB+ Station Logos

Maximise image compression without artefacts that affect legibility
Exclude all EXIF, preview, thumbnail and other metadata
File sizes of 15 kbytes or less are typical

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A.2 Design Considerations: Vehicle Manufacturers

Visual and Text Content is easily and fully legible

“Show the content sent by the broadcaster as intended while remaining safe”

Visual considerations:

The driver should not have to interact to see visuals and/or text information when they select a service to listen to
Display visuals at the highest physical screen space available
Do not change the aspect ratio of logos or visuals
Do not rescale logos or visuals up by more than 100% (x2), or down by more than 50% (x0.5).

Text considerations:

Display as much text information as possible without scrolling
Scroll text information automatically if it overspills the available display area
Display the full (16 character) station name
Do not scroll the station name

Text and Visual considerations:

If it is possible to expand the available space for text information / visual information, show this clearly to the driver on the display (e.g. symbol or similar).
Do not crop logos or visuals, or truncate text information

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A.2 Design Considerations: Vehicle Manufacturers

Service Lists are logically ordered and easy to navigate

Service List Ordering and Prominence

Service lists should be presented in the order - letters, numbers, punctuation
Service lists should ignore case sensitivity of alphabetical characters
Use the Unicode UCA to get the correct alphabetical and numerical ordering for the current Locale
NOTE: Some countries require "prominence" of specific services. In that case, the manufacturer can choose how to achieve that prominence, whilst achieving the local regulation. Suggested approaches:

List split into two sections - "prominent" services and then the remaining services
"Prominence" filter - button that filters service list to "prominent" services only
Highlight "prominent" service

Service List Length

Service Lists may get very long (more than 100 entries).
Consider strategies to aid navigation. Suggested approaches:

Alphabetical jump list
Collapsing identical services into a single entry (n.b. Define "identical" carefully)

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A.3 Common UX Components

There are a set of common / frequently used components in UX design.

On the following pages, for each common component

The likely uses for the component
How to populate the component with the correct metadata or content (where multiple options exist)
How to present the component

The guidelines do not specify

The placement of the components
If the components are mandatory to use or not
The size of the components (but consider the other design guidelines to do with legibility)

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A.3 Common UX Components - Service Navigation

Metadata = SPI service logo @ 128 x 128px, or

= SPI service logo @ 112 x 32px, or

= SPI service logo @ 32 x 32px

= default icon, or

= not shown

Presentation

X do NOT amend aspect ratio

Metadata = SPI longName, or

= SPI mediumName, or

= SPI shortName, or

= DAB+ Label, or

= DAB+ Short Label

Presentation

X do NOT overflow

X do NOT split text over lines

X do NOT truncate text

Service logo

Service Name

Components used when presenting a navigation list of services / stations

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A.3 Common UX Components - Service Information

Metadata = SPI service logo @ 600 x 600px, or

= SPI service logo @ 128 x 128px, or

= default icon, or

= not shown

Presentation

X do NOT amend aspect ratio

Physical Size >= 25mm x 25mm

Metadata = SPI longName, or

= SPI mediumName, or

= SPI shortName, or

= DAB+ Label, or

= DAB+ Short Label

Presentation

font style = 200% size, emphasis

overflow = scroll automatically

X do NOT split text over lines

X do NOT truncate text

Physical Size >= 20% of vertical screen size

Service logo

Service Name

Components used after selecting a service / radio station to listen to

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A.3 Common UX Components - Service Information

Metadata = IP Slideshow visual @ native resolution, or

= IP Slideshow visual @ 640px x 480px, or

= Slideshow visual @ 320px x 240px at 200%, or

= current SPI Programme visual, or

= Station logo @ 600px x 600px, or

= Station logo @ 320px x 240px at 200%, or

= not shown

Presentation

X do NOT amend aspect ratio

Physical Size >= 70mm in both dimensions

(smaller permitted for "thumbnails", providing� access is possible to a full-size rendering)

Metadata = DLS text, or

= RT text, or

= not shown

Presentation

font style = 100% size, normal

overflow = scroll automatically

X do NOT truncate

Physical Size >= 20% of vertical screen size

service visual information

service text information

Components used after selecting a service / radio station to listen to

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A.3 Common UX Components - Programme Information

Metadata = mediaDescription (at largest available size), or

= not shown

Presentation

X do NOT amend aspect ratio

Physical Size >= 70mm in both dimensions

(smaller permitted for "thumbnails", providing� access is possible to a full-size rendering)

Metadata = longName, or

= mediumName, or

= shortName

Presentation

font style = 200% size, emphasis

overflow = scroll automatically

X do NOT split text over lines

X do NOT truncate text

Physical Size >= 20% of vertical screen size

programme information

Programme Name

Components used when displaying Programme Information (PI)

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A.3 Common UX Components - Programme Information

Metadata = start time - end time (in local time)

Presentation

font style = 80% size, normal

Physical Size >= 8% of vertical screen size

Metadata = longDescription, or

= shortDescription, or

= not shown

Presentation

font style = 100% size, normal

overflow = scroll automatically

X do NOT truncate

Physical Size >= 20% of vertical screen size

Programme Start Time - Programme End Time

Programme Description

Components used when displaying Programme Information (PI)

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A.4 Operation Considerations: Broadcasters

Minimise distractions from updates

Do not update the text or visual more frequently than once every 20 seconds. Updates more frequent than every 20 seconds may not be shown to the driver.
Don't provide information that's already shown on the display (e.g. station name, date, time)

Text Functionality

DLS and DL+ Functionality:

Consider using DL+ tags within your DLS text string where it would describe the current audio well (e.g. artist and title of a song)
Use the DLS Remove / DL+ Item Running/Toggle commands to assist synchronising text to audio, as it will halt any scrolling and remove the text immediately

�

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A.4 Operation Considerations: Broadcasters

Slideshow Functionality

MOT Trigger Time

Use MOT Trigger Time to assist synchronising visuals to audio
Some vehicles do not currently support DAB+ Slideshow MOT Trigger Time* and will simply display the most recently received image.

Slideshow Caching

Use caching of DAB+ Slideshow images to assist with synchronising visuals to audio
Be aware that many receivers cannot cache DAB+ Slideshow images
Also note the problem with inconsistent implementation of MOT Trigger Time above

*As a workaround, you can deliver the MOT Object ahead of display time, but to prevent it being shown until the required time, hold back transmission of the final data packet. At the required display time, send the final data packet in several repetitions, and the MOT object assembly will complete, and the image will be displayed.

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A.5 Operation Considerations: Vehicle Manufacturers

Minimise driver requirements to interact

The driver should not have to interact to see visuals and/or text information when they select a service to listen to
Scroll text information automatically if it overspills the available display area
If automatic scrolling is not permitted, provide an obvious option for the driver to see more text information
If it's possible to enlarge the text/image display area, provide an obvious option for the driver
If an update to DLS/DL+ or Slideshow is received more than 20 seconds after the previous update, you may ignore it.
Monitor update times for text (DLS), DL+ and Slideshow separately.

DLS and DL+ Functionality:

Implement DLS Remove and DL+ Running/Toggle command to assist synchronising text to audio

Slideshow Functionality

Implement DAB+ Slideshow MOT Trigger Time to assist synchronising visuals to audio
Support caching of DAB+ Slideshow images to assist with synchronising visuals to audio
Implement visuals over IP (RadioVIS) where possible, and make sure your device sends its physical screen size (DPI) as well as preferred image resolution, when requesting an image

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A.5 Operation Considerations: Vehicle Manufacturers

Emergency Alerts - Alarm Announcements and Automatic Safety Alerts

Alerts for drivers can be provided by:

Announcements of type Alarm (EN 300 401)
Automatic Safety Alerts (TS 104 089)

Alarm Announcements can apply to a single service or to all services

Alerts should trigger an interruption of current audio function, and switch to the audio and visual of the alerting service

Do not obstruct the visual content with dialog boxes - if you need to provide an option to cancel the alert, provide it so it does not block the visual content or station name

You may provide a driver option to disable interruptions from emergency alerts; consider providing a modified visual indication even if interruptions are disabled.

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A.5 Operation Considerations: Vehicle Manufacturers

Automatically Start the Radio on "Ignition On" condition

Radio should turn on automatically at the last state / station when the vehicle "ignition" is "turned on" - even if the radio functionality is implemented as an "app".
Radio service list should be positioned at the currently / most recently tuned station

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A.6 Further Considerations

Justification for producing visual content

Producing and transmitting visuals is expensive, so commercial broadcasters need to sell visualisation (text and images) of audio advertising to meet their business case.

They can only do that if the display of content to drivers is accurately timed and consistently visible.

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A.7 Voice Control

Voice Control

Manufacturers should reference <alias> and <phoneme> elements in SPI provided by broadcasters to determine accurate voice recognition and voice reproduction of text elements, such as station and programme names

Broadcasters should provide <alias> elements in their SPI where there is potential for consumers to reference the station using colloquial or unofficial names

Broadcasters should provide <phoneme> elements for all textual elements in their SPI.�Guidance on how to do this is available from WorldDAB and RadioDNS

Hardware and technical references:

Service & Programme Information – ETSI TS 102 818 v.3.51 (sections 5.14 / 5.15)

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B. Example Visuals

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Example Visuals

❌ Text size is not legible

❌ Too much text to read in 1 second

❌ Background is very busy

❌ Text positioning is poor (overflows)

❌ Too much text to read in 1 second

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Example Visuals

✅ Text is legible

✅ Artist photo is clear / good quality

✅ Everything can be understood in 1 second

✅ Text is legible

✅ Album art is clear / good quality

✅ Everything can be understood in 1 second

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Example Visuals

✅ Text is legible

✅ Artist photo is clear / good quality

✅ Everything can be understood in 1 second

✅ Text is legible

✅ Artist photo is clear / good quality

✅ Everything can be understood in 1 second

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C. NABA UX Guidelines:

Comparison Table

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Background: UX Guidelines for North America - NABA

The North American Broadcasters Association (NABA) has produced a set of UX Guidelines based on the 4th version of this document (January 2022)

The development of these Guidelines aims to give a clear picture to vehicle manufacturers and broadcasters of how radio should appear and function for users in North America

The NABA Guidelines are on the whole the same as these Guidelines however due to market conditions do differ in parts

A list of these differences is provided in this Annex

To receive a full version of the UX Guidelines for North America visit the NABA web site at https://nabanet.com/radio-in-car-user-experience-guidelines/

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NABA UX Guidelines: Comparison Table

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D. Glossary of Terms

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Annex Glossary of Terms

Text Message

DAB+ DLS, FM RT or RadioDNS /text.

Manufacturers

Text Messages must always be automatically updated on the display as they are received. Commands to “REMOVE” messages must be respected. The receiver may restrict text message change rate to one update every 20 seconds.

Broadcasters

- Text Messages should describe accurately what is being broadcast now, or something directly relevant to the listener.

- Text Messages should not be updated more than once every 20 seconds.

- It is important for Car that updates are not more frequent then 20s to comply with law of the country in which the cars will be sold plus international laws covering this area. Either Broadcasters slow down upcoming changes or car manufacturer will do it on their side.

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Annex Glossary of Terms

Service Label

DAB+ Service Label, FM PS, or RadioDNS Name elements.

Manufacturers

There is no requirement to update a Service Label whilst receiving a Service (e.g. “Scrolling PS”)

In markets where PS is unreliable, it can be discarded in favour of DAB+ Service Label or RadioDNS Name elements, if the service is correctly identified (e.g. DAB+ SId = RDS PI = RadioDNS bearer match)

Display the longest Service Label that can fit the available display space without scrolling:

RadioDNS <longName> element
DAB+ Service Label (16 characters) or RadioDNS <mediumName> element
FM RDS PS (8 characters) or RadioDNS <shortName> element

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Annex Glossary of Terms

Station Logo

DAB+ EPG <mediaDescription> element

RadioDNS <mediaDescription> element

Manufacturers

The Station Logo must be displayed at the highest resolution for the available display space.

The Station Logo with the closest available resolution must be selected for display, and scaled to fit, but the aspect ratio must not be changed

See WorldDAB / Radio DNS guidance on Provision of Station Logos here

Broadcasters

You must provide 5 versions of your logo on IP, and/or 4 versions over DAB+ SPI

The Station Logo should be allowed to be cached for up to 30 days.

The Station Logo must not feature any transparency layers

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Annex Glossary of Terms

Phonemes

Phonemes describe how words are pronounced

Phonemes are good for voice recognition and voice control

Phonemes help to improve voice recognition better detect spoken words and allow better voice output to the User

Phonemes are different for different languages or dialects

Phonemes are part of Station Corporate Identity and Corporate Design

Station names are often pronounced differently then transmitted and shown to user

Example:

NRJ pronounced as Energy as phoneme ehnərʤi
2FM pronounced as Twofm as phoneme tuˈehˈfm
Most systems will not understand the user if he asks for 2FM or NRJ because voice assistant would need to have different Phonemes for different pronunciation NRJ -> nrj or ˈehnərʤi

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E. Local Legislation

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Local Legislation & Disclaimer

These are Guidelines only and WorldDAB bears no liability for their implementation or resulting performance and impact. It is the responsibility of broadcasters and car-makers to comply with all relevant local, national and international legislation which should always override these Guidelines.

Broadcasters - consider that local, national or international legislation may prevent some content being displayed

Manufacturers - you shall always follow local, national and international legislation above this document, but please contact WorldDAB if you have to modify behaviour in some markets

�

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WorldDAB ETI Library & Disclaimer

WorldDAB Members have access to an ETI Library which provides country specific examples of use cases for testing.

This library has snapshots of DAB services and features on-air provided by players in the markets. It is assumed but not confirmed that these files comply with local, national and international legislation applied to the market and the content broadcasters send to the car.

It is not however guaranteed by those providing files or by WorldDAB that this is the case and therefore WorldDAB holds not responsibility if these files are not compliant with the legislation mentioned above.

Further information about the WorldDAB ETI Library can be found here:

https://www.worlddab.org/resources/worlddab-eti-library

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About WorldDAB

WorldDAB is the global forum for digital radio, facilitating the adoption and implementation of DAB digital radio.

WorldDAB is the global industry forum for digital radio, facilitating the adoption and implementation of broadcast digital radio based on DAB / DAB+.

WorldDAB provides advice and support on all aspects of the switch from analogue to digital radio including regulation, licensing, technical trials, network build out, marketing and production of new digital radio content.

WorldDAB has over 100 member organisations bringing together 1500+ digital radio experts from 37 countries across the world, representing public and commercial radio broadcasters, media regulators, broadcast network providers, through to manufacturers of receivers, chips, professional equipment and automobiles.

WorldDAB is a not-for-profit association with legal personality governed by Swiss law and by its Statutes: www.worlddab.org

To find out more about this group and how to join contact rosemary.smith@worlddab.org

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