HERE Map Content Developer's Guide

Lane Traversal

Definition

Lane Traversal defines lane connectivity; how lanes are connected between origin and destination lanes for making a specific manoeuvre. Lane connectivity is modelled via a combination of Lane IDs which form the path through the junction.

Usage

The Lane Traversal condition can be used to provide specific lane-level visual or audible instructions, such as "Stay in the right lane to turn right," for traversing through a junction.

Rules

Inclusion:

  • Lane Traversal is part of the Extended Lane content, which is generally applied at the following locations, within the scope set by HERE:
    • Highway-to-Highway connectors.
    • Motorway and non-motorway exit ramps with more than one exiting lane.
    • Points where Special Explication exists.
    • Roads between Controlled Access roads and all Airport POIs that are flagged as National Importance. This includes all POI with Facility Type = 4581 (Airports and Terminals).
    • Surface street intersections with complicated lane configurations, including the following:
      • Exit ramps with more than one lane

      • Intersections involving five or more meeting roads.

      • Intersections with multiple left or right turn lanes

      • Roundabouts or Special Traffic Figures with multiple lanes

      • Where lane dividers longer than 50 metres force vehicles into specific lanes prior to the intersection

      • Intersections where angles of streets make it difficult to determine how the roads connect

      • Points requiring Special Explication

    • Extended Lane content is not applied in the following situations:

      • To or from any lane that is not wide enough for an automobile, except motorcycle only lanes.

      • To or from roads/paths that are not meant for regular navigation by most, if not all, vehicle types and are not navigationally significant, for example, parking lot roads, cemetery roads, petrol/gasoline station roads, alleys, walkways, weigh stations, and so on

      • At toll booth plazas if the toll booth plaza is applied with Transition Area = Y.

      • For example, a road has two turn lanes, both to the left, so the only possible manoeuvre is to the left. In this case, the two lanes are not considered turn lanes but as the roadbed itself.

On Interchanges:

  • For each included interchange, Lane Traversal conditions are applied at two specific points:
    • The “transition point” is the point along the where lane marking (or in some cases road signage) clearly indicates to the driver that a lane or set of lanes is required to continue along a route.
    • The “split point” is the point along the where it is no longer possible to travel across the sets of lanes from either direction to continue along the route. The split point coincides in the database with a “point of no return” where the driver can no longer change lanes.
  • The following image shows the relationship between the transition point and split point in reality and in the HERE database representation.

Specification

Lanes that are involved are defined for the Lane Traversal condition. A Lane Traversal condition has at minimum an "In Lane" and an "Out Lane." There could be more lanes if traversing a complex intersection, see the image below.

The first and last Lane ID involved for the Lane Traversal condition represent the important content for Lane Traversal information: these define the explicit Lanes which are connected when traversing the junction. The intermediate lane(s) for the Lane Traversal condition are merely included to complete the lane strand information and provide a fully connected set of Lanes.

If more than two road segments are involved in the same Lane Traversal condition, see the following image, a default lane object for the intermediate road segment(s) is used to ensure lane connectivity. Lane 1 is used as default for the lane(s) present on the road segment(s) internal to the Lane Traversal condition, independent of the total number of lanes on the road segments.