Added an offline-testable client for the four xROAD traffic-volume API layers, with typed CQL construction, separate HTTP execution, GeoJSON and JSON-encoded CSV parsing, three layer schemas, typed data.table results, three-state CCTV flags, body-based API failure detection, transient-only retries, and request throttling. Recorded probe responses pin the deployed property names, HTTP 200 payload-cap error, invalid quoted-CQL response, empty-result ambiguity, CSV coordinate precision, and form 4’s two-digit time_slot, 12-digit request time_code, and observed "0"/"2" processing flags.
read_jartic_traffic() reads a JARTIC type B (cross-sectional traffic volume) CSV file, converting it from CP932 and returning a data.table keyed on datetime (JST).
jartic_type_b_loc_tiny() derives the observation-location table by splitting location_name into location_from / location_to. The split happens on the first arrow only and returns a data.table, so the class matches the rest of the API; names without an arrow keep the whole value in location_from, and names with more than one arrow keep the remainder in location_to instead of discarding it. This drops the tidyr dependency.
read_jartic_traffic() now warns instead of staying silent when bytes in location_name are not valid CP932 and decode to NA.
read_jartic_traffic() reads the layout off the first line of the file instead of assuming one (#3). Every published file carries a header row, which is now dropped rather than read as an observation; a file that starts with an observation is still read in full. Files published before 2018-02 have nine columns and no link version, and are returned with the same ten columns as the current layout, with link_ver set to NA. A file whose width is neither 9 nor 10, or that holds a header row and nothing else, is an error rather than a silent misread.
read_jartic_traffic() accepts the 2017/8/1 0:00:00 timestamp used by most providers before 2018-02, alongside the current 2026/06/01 00:00, and warns when a value still fails to parse instead of leaving NA unannounced (#3).
jartic_provider records the 51 JARTIC data providers (47 prefectures, with Hokkaido split into its 5 police headquarters areas).