HERE Map Content Developer's Guide

Blackspot

Definition

Blackspot identifies intersections, points or stretches along a road with an unusually high number of accidents. The Blackspot definition is based on what the external source data defines as a blackspot or based on posted signs at intersections and roads. The Blackspot definition can vary between sources, regions, or countries.

Usage

Blackspot can be used to warn drivers as they approach blackspots. This warning can be audible, visual by displaying an exclamation mark on the screen, or both. The information can be provided at the location itself, as well as in advance, such as the warning “Blackspot in 200 metres”.

Specification

  • The Blackspot inclusion is based on posted blackspot locations or blackspot source data. The Blackspot definition as defined by the external source data is used for Blackspot inclusion.

  • Blackspot conditions are applied on roads and intersections where applicable and available.

  • A Blackspot condition can be a road segment–node or a road segment only condition. Blackspot conditions are applied as follows:
    • Road Segment–Node condition: Involves one Road segment as origin and one connected node as the destination in case the Blackspot is referencing a point, or single node intersection, see the following figure. Points can be based on coordinate references in source data or based on posted signs indicating a blackspot location. Blackspot signs are not standardised and vary widely between regions and countries.
    • Road Segment Only condition: Is applied to road segment(s) in case the Blackspot is referencing a stretch of road or intersection road segments, see the figure "Road Segment Only". If a blackspot sign indicates an extent, then the blackspot sign is applied on the road segment(s) that reflect the extent indicated on the sign.
Figure 1. Road Segment–Node
Figure 2. Road Segment Only