General Information
OpenDrive is an open data format to describe street networks and is commonly used for driving simulations. The current format specification, rev. 1.4 was published in 2015 by VIRES Simulationstechnologie GmbH. The two most frequently used coordinate systems within the standard are an inertial, right handed coordinate system according to ISO 8855 and a so-called track system that applies along a defined reference line. All roads are represented using a reference line described as a sequence of geometric primitives such as straight lines, spiral curves, cubic polynoms and parametric cubic curves. Along this reference line a variety of road properties such as an elevation profile, traffic signs or lanes can be defined. Multiple ‘Lane Sections’ with a constant number of lanes along a reference line may be defined in ascending order. The properties of each lane, however, may vary and are defined relative to the start of the corresponding lane section (Dupuis et al. 2015). Additionally, a road’s superelevation crossfall as well as a lateral profile can be modelled. Lanes are identified by a unique number per lane section and ordered in sequence starting from 0, ascending to the left and descending to the right (relative to the reference line direction). The number of lanes is unlimited and the reference line itself is defined as lane 0 with width zero. In some situations, a ‘Lane Offset’ can be introduced in order to shift the lane profile. This can be useful to describe a turning lane by offsetting lane 0 using a cubic polynom. To make navigation through a road network possible, roads are linked either by a successor/predecessor linkage or via junctions. If the linkage between two roads is clear a standard link can be used. Junctions are required if an incoming road could be linked to more than one successive road. OpenDrive provides two approaches to describe surfaces parametrically. The standard description contains parameters per lane for ‘surface material code’, ‘roughness’ and ‘friction’. More detailed information on road surface data may be included in an extended description. Road networks may be geo referenced using a projection definition formatted as ‘proj4’-string.