Implementation:CARLA simulator Carla Signal

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

Overview

The Signal class represents a traffic signal or sign in the OpenDRIVE road network, storing its position, orientation, type, dimensions, and associated controllers.

Description

carla::road::Signal is a MovableNonCopyable class modeling an OpenDRIVE signal element with properties:

• Position -- road ID, s-coordinate, t-offset (lateral), z-offset, horizontal offset, pitch, and roll
• Identity -- signal ID, name, country code, type, subtype, and text
• Orientation -- encoded as "+", "-", or both, mapped to the SignalOrientation enum (Positive, Negative, Both)
• Dynamic flag -- whether the signal changes state (parsed from "yes"/"no" string)
• Dimensions -- height, width, and a numeric value (e.g., speed limit value)
• Dependencies -- a vector of SignalDependency objects linking to other signals
• Transform -- a geom::Transform for the signal's 3D world position
• Controllers -- a set of ContId references

Usage

Use this class to query traffic signal properties when processing signal references along a route, implementing traffic light logic, or placing signal assets in the 3D world.

Code Reference

Source Location

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

Signature

enum SignalOrientation { Positive, Negative, Both };

struct SignalDependency {
  std::string _dependency_id;
  std::string _type;
};

class Signal : private MovableNonCopyable {
public:
  Signal(RoadId road_id, SignId signal_id, double s, double t,
         std::string name, std::string dynamic, std::string orientation,
         double zOffset, std::string country, std::string type,
         std::string subtype, double value, std::string unit,
         double height, double width, std::string text,
         double hOffset, double pitch, double roll);

  RoadId GetRoadId() const;
  const SignId &GetSignalId() const;
  double GetS() const;
  double GetT() const;
  bool GetDynamic() const;
  const std::string &GetName() const;
  SignalOrientation GetOrientation() const;
  double GetZOffset() const;
  const std::string &GetCountry() const;
  const std::string &GetType() const;
  const std::string &GetSubtype() const;
  double GetValue() const;
  double GetHeight() const;
  double GetWidth() const;
  const geom::Transform &GetTransform() const;
  const std::set<ContId> &GetControllers() const;
};

Import

#include "carla/road/Signal.h"

I/O Contract

Input	Type	Description
Various | All signal attributes from OpenDRIVE XML

Output	Type	Description
Various getters | Signal type, position, orientation, dimensions
geom::Transform | 3D world position and rotation

Usage Examples

const auto &signals = map_data.GetSignals();
for (const auto &[id, signal] : signals) {
  if (signal->GetDynamic()) {
    auto type = signal->GetType();
    auto transform = signal->GetTransform();
  }
}

Related Pages

• Environment:CARLA_simulator_Carla_Simulation_Runtime