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78 seconds. A narrated explainer; the transcript is below. The written guide includes additional detail.
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- 0:00In a mixed traffic file, the meaning
- 0:02of a record depends on its surrounding
- 0:04definitions. Reading each line as an unrelated
- 0:07spreadsheet row loses relationships that the system
- 0:10can check. A header block begins with
- 0:13H zero and closes with H nine.
- 0:16The mixed-file checks detect orphaned, nested and
- 0:19unclosed boundaries, and look for compulsory definitions
- 0:22in completed blocks. Lane consistency compares the
- 0:26totals in L zero with the L
- 0:28one definitions. Two declared lanes but one
- 0:32lane definition is a relationship problem, even
- 0:34if both records contain valid numbers. Variable
- 0:38vehicle records use their declared counts and
- 0:40schema rules to determine expected field lengths.
- 0:44Dropping a repeated value can make the
- 0:46physical record disagree with its own count.
- 0:49These contextual checks depend on the mixed-file
- 0:52route. A standalone record template cannot establish
- 0:55all the relationships available in a complete
- 0:57file with active headers. Preserve the original
- 1:01record order and review the reported source
- 1:03line. Correct the header, lane definition or
- 1:06record length at source, then rerun. Keep
- 1:09structural validity distinct from the accuracy of
- 1:12the measured traffic.
A record needs its context
In a mixed traffic file, the meaning of a record depends on its surrounding definitions. Reading each line as an unrelated spreadsheet row loses relationships that the system can check.
A header block begins with H zero and closes with H nine. The mixed-file checks detect orphaned, nested and unclosed boundaries, and look for compulsory definitions in completed blocks.
Reconcile the lane definitions
Lane consistency compares the totals in L zero with the L one definitions. Two declared lanes but one lane definition is a relationship problem, even if both records contain valid numbers.
Variable vehicle records use their declared counts and schema rules to determine expected field lengths. Dropping a repeated value can make the physical record disagree with its own count.
Read the block that gives a record meaning
Retain H0, the intervening definitions and H9 with their subsequent traffic records. A familiar numeric record identifier can mean different things in header and traffic contexts. The parser’s active definitions determine how the following records are interpreted, so an isolated line is often insufficient evidence.
Review declared lanes and vehicle structure in the original sequence. Do not sort records or remove a header merely to make a flat table easier to read. Keep parsing failures distinct from engineering questions about the measurements and preserve the source file during investigation.
Read a mixed file as a stream
These contextual checks depend on the mixed-file route. A standalone record template cannot establish all the relationships available in a complete file with active headers.
Preserve the original record order and review the reported source line. Correct the header, lane definition or record length at source, then rerun. Keep structural validity distinct from the accuracy of the measured traffic.
Sources and scope
This guide describes the platform workflow; it does not establish a requirement of a TMH manual. Platform review and certification are described in the product documentation.
Put it into practice
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