HERE Traffic API
Traffic API Developer's Guide

# Common Acronyms

The table below lists the common acronyms used throughout this document and their meaning.

Table 1. Acronyms and Definitions
Acronym Definition
CF The Current Flow for the location. Current Flow is comprised of several attributes that describe how traffic is moving at location.
CN The Confidence attribute, which is a number between 0.0 and 1.0 indicating the percentage of real time data included in the speed calculation.
• A value greater than 0.7 and less than or equal to 1.0 indicates real time speeds
• A value greater than 0.5 and less than or equal to 0.7 indicates historical speeds
• A value greater than 0.0 and less than or equal to 0.5 indicates speed limit
• A value of -1.0 indicates road closed or unable to calculate

To only report speeds where real time data is available, we recommend that you include speeds with a confidence greater than 0.7 CN and include road closures with a value = -1.0 CN

FI The entry for each Flow Item in the specified direction.
FIS A list of Flow Items (FI), one list for each direction of the roadway(RW). (1-many)

The FI in each FIS section is guaranteed to be contiguous and in the order of the driving direction. If there is a break in continuity on an RW, then there are 2 or more FIS elements in the RW.

JF A number between 0.0 and 10.0 indicating the Jam Factor, which represents the expected quality of travel. When there is a road closure, the Jam Factor is 10.

However, a reversible not routable status uses a Jam Factor of -1 as most applications do not want to display a blackout as a closure on the map. As the number approaches 10.0, the quality of travel degrades. -1.0 indicates that a Jam Factor could not be calculated.

TS The Traversable Status (TS) can be set to C for Closed, O for Open, and RNR for Reversible not routable. When TS is set to C, this is the standard road closure and the other attributes are then set to: SP=-1, SU=-1, JF=10.0. This is consistent with how TML Flow has always indicated closures since TML 2.0. When TS is set to O, the road is open for traffic. This includes reversible roads that are open.

When TS is set to RNR the reversible road is not routable and the other attributes are then set to: SP=-1, SU=-1, JF=-1. The application can deal with reversible not routable in any way, but it is recommended that it is used to indicate not routable and to not show traffic on this roadway in the map display. This is the best source of information when routing through reversible lanes. This data is more accurate than any source, including HERE Maps, as published reversible information can be changed based on daily traffic flow or special events. For reversible roads, both full linears are not routable for portions of the day when the road direction is being switched. There is a possibility that portions of a reversible road are marked as Closed rather than RNR; when this happens, both directions of the reversible are closed, which can happen for construction or major accidents.

SU A number that indicates the average Speed Uncut (SU) for the road segment. Uncut means that the speed limit for the road segment is ignored. Speeds that are over the speed limit are included in the average.
SP A number that indicates the average Speed (SP) for the road segment. The average does not take speeds that are over the speed limit into account. Speeds that are over the speed limit are trimmed down to the speed limit.
QD This data type indicates the Queuing direction (QD) of the traffic. When traffic becomes congested, a queue of vehicles begins to build up in the opposite direction to the driving direction. The value can be "+" or "-". The value "-" indicates that the traffic is queued in the opposite direction to the driving direction.