Implementation:CARLA simulator Carla Road Interface

Knowledge Sources	CARLA
Domains	Road Network, Simulation
Last Updated	2026-02-15 05:00 GMT

Overview

The Road class represents a single road segment in the OpenDRIVE road network, containing lane sections, geometry, elevation, and connectivity information.

Description

carla::road::Road is a MovableNonCopyable class that models one road element from the OpenDRIVE specification. Each road has:

• Identity -- a unique RoadId, name, length, and whether it belongs to a junction
• Lane sections -- a map of LaneSection objects indexed by road-coordinate s, providing access to all lanes at any given distance along the road
• Connectivity -- successor and predecessor road IDs, plus resolved next/previous road pointers
• Geometry and elevation -- accessed through templated GetInfo<T>(s) methods that retrieve RoadInfoGeometry, RoadInfoElevation, and lane offset records
• Directed points -- methods to compute center-line points with elevation and lane offset applied
• Nearest point/lane -- methods to find the closest point on the road and the nearest lane to a given location

The class uses an InformationSet to store heterogeneous road information records and a LaneSectionMap for efficient lane section lookup by distance.

Usage

Use this class when you need to query properties of a specific road segment, retrieve lanes at a given distance along the road, compute directed points on the road center line, or traverse the road's connectivity graph.

Code Reference

Source Location

• Repository: CARLA
• File: LibCarla/source/carla/road/Road.h

Signature

class Road : private MovableNonCopyable {
public:
  Road() = default;

  const MapData *GetMap() const;
  RoadId GetId() const;
  std::string GetName() const;
  double GetLength() const;
  bool IsJunction() const;
  JuncId GetJunctionId() const;
  bool IsRHT() const;

  Lane &GetLaneByDistance(double s, LaneId lane_id);
  std::vector<Lane*> GetLanesByDistance(double s);
  RoadId GetSuccessor() const;
  RoadId GetPredecessor() const;
  Lane &GetLaneById(SectionId section_id, LaneId lane_id);
  Lane *GetNextLane(const double s, const LaneId lane_id);
  Lane *GetPrevLane(const double s, const LaneId lane_id);
  LaneSection *GetStartSection(LaneId id);
  LaneSection *GetEndSection(LaneId id);

  std::vector<Road *> GetNexts() const;
  std::vector<Road *> GetPrevs() const;

  element::DirectedPoint GetDirectedPointIn(const double s) const;
  const std::pair<double, double> GetNearestPoint(const geom::Location &loc) const;
  const std::pair<const Lane *, double> GetNearestLane(const double s, const geom::Location &loc, uint32_t type) const;

  template <typename T> const T *GetInfo(const double s) const;
  template <typename T> std::vector<const T*> GetInfos() const;

  auto GetLaneSections() const;
  auto GetLaneSectionsAt(const double s) const;
  std::map<LaneId, const Lane *> GetLanesAt(const double s) const;
  double UpperBound(double s) const;
};

Import

#include "carla/road/Road.h"

I/O Contract

Input	Type	Description
double | Distance along the road from its start
LaneId | Lane identifier (negative = right, positive = left, 0 = center)
geom::Location | 3D location for nearest-point queries

Output	Type	Description
element::DirectedPoint | 3D point with tangent, pitch on the road center line
Lane & | Reference to a lane at the specified position
pair<double, double> | (s distance, Euclidean distance) to nearest center point

Usage Examples

// Access a road from MapData
const auto &road = map_data.GetRoad(road_id);

// Get a directed point at distance s=50 along the road
auto dp = road.GetDirectedPointIn(50.0);

// Get all lanes at s=30
auto lanes = road.GetLanesAt(30.0);

// Find nearest lane to a location
auto [lane_ptr, dist] = road.GetNearestLane(50.0, location);

Related Pages

• Environment:CARLA_simulator_Carla_Simulation_Runtime