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ITIS Phrase Tables, Draft [issued: 04-11-09]
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8
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This is a draft document of the SAE ATIS committee, subject to change.
"disabled vehicle right lane blocked ". Observe that capitalization and punctuation marks can vary slightly
in this.
The second case involves the limited use of numerical values in messages. Historically RDS allowed only
a few "common" numbers to occur in the messages.¹ In ITIS phrases, as a function of the methods of SAE
J2540, numerical values can be inserted in between phrases as needed to express values.² An example
would be RDS message #421 which is rendered as "Closed ahead, Stop and go traffic for 5 miles".³ An
equivalent message made up of ITIS components would be [0771,0258,7721,0005,8712] which is rendered
as "Closed ahead Stop and Go traffic for 5 miles ". Depending upon the way in which the numeric value is
encoded, ordinal post fix characters can also be automatically added at expansion. In addition, a list of
common unit values (seconds, minutes, dollars, mph, miles, etc…) is also present in the ITIS list.
A number of the "message canceled" type of phrases have been preserved in ITIS list for backward
compatibility. As an operational concept the use of the these phrases is not encouraged. Specific messages
of this type which may be removed or replaced in the future are denoted with the comment "Not
Recommended" in the tables.
In addition it should be pointed out that the data contents found in the ATIS messages (and the rest of ITS)
contain a broad spectrum of other elements which are intended to hold concepts like the time period over
which a message is valid. These data elements SHOULD be used as intended and the phrase sections of
the message SHOULD NOT be used to circumvent them.
5.3
Use in the TMDD ERM Message
When used in constructing an Event Reporting Messages (ERM) message from the TMDD MS/ETMC2
message set some additional considerations and restrictions apply in order to maintain a dual perspective on
the encodings found in the ERM message. This allows an "ERM-centric" practitioner to exchange data
with an "ATIS centric" one without involving translations which would detract from interoperability.
The key to this dual view is to appreciate that: ATIS tends to view a collection of phrases as representing
one atomic element which can be uniformly handled upon receipt, the ERM perspective describes an event
element as the structured combination of phrases, causes, advice, quantifiers and free text each in its own
ASN1 element. Both perspectives are valid. ERM receiving implementations can use this to good effect in
various sorting and automatic classification functions (which the SAE perspective also supports). The
following is an excerpt from the key portion of the ERM message.
Event-description ::= CHOICE
{
event-phrase
[1]
SEQUENCE OF Event-type,
event-cause
[2]
SEQUENCE OF Event-type,
1
The latter "multi-block" RDS messages of Alert+ does allow a value to be delimited in an element
of the message which is then inserted into the phrases based on a predetermined use and location. This
was considered and rejected in favor of having a more generalized approach in J2540.
2
Not all uses of ITS can support this; for example ERM (a message which is part of the TMDD
standards) prohibits numeric and free text insertions. In the ERM case, other elements in the message can
contains such values.
3
To the SAE Technical Editor: [remove upon publication] You will observe that at times
there are extra spaces in some of the quotes and that the sentence period occurs outside the quote in some
sentences. Preserve this formatting. The quote is a literal value and the period is not a part of it. The
dangling spaces are also an effect of this; do not remove them.