Using vehicle probe points with Traffic Analytics

HERE collects probes from different types of vehicles, and when a single road segment sees multiple probes in a single epoch, it averages their speeds together to provide a mean speed for that epoch. If some vehicles spend more time than others on that road segment in that epoch, or if some of those vehicles produce probe points more frequently than others, then each vehicle doesn't have the same impact on the mean speed as the others.

In most cases, the effect of this imbalance is minimal, and using per-probe speed averaging is simplest. But using the Per Vehicle option, Traffic Analytics can first create an average speed per vehicle and then average the vehicle speeds together individually. This has the statistical effect of weighting all vehicles equally. HERE recommends choosing this option if you are doing long-term trend analysis, since it compensates for changes in the HERE sample fleet. This option applies only to probe data. Path data is, by definition, already limited to one path per vehicle (per epoch per road segment).

Be aware that this option is primarily only distinctive in link queries at five-minute epochs. When Traffic Analytics aggregates to longer epochs or for TMC-level output, it simply aggregates the data for each included epoch and link.

Vehicles are counted once for each five-minute epoch in which they occupied the road segment, and once for each link in a TMC they reported on.

The observation counts for each speed are the sum of all the counts for the links and five-minute epochs in the output dataset.