diff --git a/cartographer/cloud/internal/client/pose_graph_stub.cc b/cartographer/cloud/internal/client/pose_graph_stub.cc
index 7af3a58..96e9888 100644
--- a/cartographer/cloud/internal/client/pose_graph_stub.cc
+++ b/cartographer/cloud/internal/client/pose_graph_stub.cc
@@ -108,6 +108,10 @@ bool PoseGraphStub::IsTrajectoryFinished(int trajectory_id) {
   LOG(FATAL) << "Not implemented";
 }
 
+bool PoseGraphStub::IsTrajectoryFrozen(int trajectory_id) {
+  LOG(FATAL) << "Not implemented";
+}
+
 std::map<int, mapping::PoseGraphInterface::TrajectoryData>
 PoseGraphStub::GetTrajectoryData() {
   LOG(FATAL) << "Not implemented";
diff --git a/cartographer/cloud/internal/client/pose_graph_stub.h b/cartographer/cloud/internal/client/pose_graph_stub.h
index f07002e..9c7e90d 100644
--- a/cartographer/cloud/internal/client/pose_graph_stub.h
+++ b/cartographer/cloud/internal/client/pose_graph_stub.h
@@ -40,6 +40,7 @@ class PoseGraphStub : public ::cartographer::mapping::PoseGraphInterface {
   GetTrajectoryNodePoses() override;
   std::map<std::string, transform::Rigid3d> GetLandmarkPoses() override;
   bool IsTrajectoryFinished(int trajectory_id) override;
+  bool IsTrajectoryFrozen(int trajectory_id) override;
   std::map<int, mapping::PoseGraphInterface::TrajectoryData> GetTrajectoryData()
       override;
   std::vector<Constraint> constraints() override;
diff --git a/cartographer/mapping/2d/pose_graph_2d.cc b/cartographer/mapping/2d/pose_graph_2d.cc
index 65454b3..d8f1146 100644
--- a/cartographer/mapping/2d/pose_graph_2d.cc
+++ b/cartographer/mapping/2d/pose_graph_2d.cc
@@ -417,6 +417,10 @@ void PoseGraph2D::FreezeTrajectory(const int trajectory_id) {
   });
 }
 
+bool PoseGraph2D::IsTrajectoryFrozen(const int trajectory_id) {
+  return frozen_trajectories_.count(trajectory_id) > 0;
+}
+
 void PoseGraph2D::AddSubmapFromProto(
     const transform::Rigid3d& global_submap_pose, const proto::Submap& submap) {
   if (!submap.has_submap_2d()) {
diff --git a/cartographer/mapping/2d/pose_graph_2d.h b/cartographer/mapping/2d/pose_graph_2d.h
index a6230e5..b69222d 100644
--- a/cartographer/mapping/2d/pose_graph_2d.h
+++ b/cartographer/mapping/2d/pose_graph_2d.h
@@ -93,6 +93,7 @@ class PoseGraph2D : public PoseGraph {
   void FinishTrajectory(int trajectory_id) override;
   bool IsTrajectoryFinished(int trajectory_id) override;
   void FreezeTrajectory(int trajectory_id) override;
+  bool IsTrajectoryFrozen(int trajectory_id) override;
   void AddSubmapFromProto(const transform::Rigid3d& global_submap_pose,
                           const proto::Submap& submap) override;
   void AddNodeFromProto(const transform::Rigid3d& global_pose,
diff --git a/cartographer/mapping/3d/pose_graph_3d.cc b/cartographer/mapping/3d/pose_graph_3d.cc
index d690ef1..55ecb3e 100644
--- a/cartographer/mapping/3d/pose_graph_3d.cc
+++ b/cartographer/mapping/3d/pose_graph_3d.cc
@@ -435,6 +435,10 @@ void PoseGraph3D::FreezeTrajectory(const int trajectory_id) {
   });
 }
 
+bool PoseGraph3D::IsTrajectoryFrozen(const int trajectory_id) {
+  return frozen_trajectories_.count(trajectory_id) > 0;
+}
+
 void PoseGraph3D::AddSubmapFromProto(
     const transform::Rigid3d& global_submap_pose, const proto::Submap& submap) {
   if (!submap.has_submap_3d()) {
diff --git a/cartographer/mapping/3d/pose_graph_3d.h b/cartographer/mapping/3d/pose_graph_3d.h
index c426160..9e0cc93 100644
--- a/cartographer/mapping/3d/pose_graph_3d.h
+++ b/cartographer/mapping/3d/pose_graph_3d.h
@@ -92,6 +92,7 @@ class PoseGraph3D : public PoseGraph {
   void FinishTrajectory(int trajectory_id) override;
   bool IsTrajectoryFinished(int trajectory_id) override;
   void FreezeTrajectory(int trajectory_id) override;
+  bool IsTrajectoryFrozen(int trajectory_id) override;
   void AddSubmapFromProto(const transform::Rigid3d& global_submap_pose,
                           const proto::Submap& submap) override;
   void AddNodeFromProto(const transform::Rigid3d& global_pose,
diff --git a/cartographer/mapping/internal/testing/mock_pose_graph.h b/cartographer/mapping/internal/testing/mock_pose_graph.h
index 92c103f..fccd967 100644
--- a/cartographer/mapping/internal/testing/mock_pose_graph.h
+++ b/cartographer/mapping/internal/testing/mock_pose_graph.h
@@ -44,6 +44,7 @@ class MockPoseGraph : public mapping::PoseGraphInterface {
       mapping::MapById<mapping::NodeId, mapping::TrajectoryNodePose>());
   MOCK_METHOD0(GetLandmarkPoses, std::map<std::string, transform::Rigid3d>());
   MOCK_METHOD1(IsTrajectoryFinished, bool(int));
+  MOCK_METHOD1(IsTrajectoryFrozen, bool(int));
   MOCK_METHOD0(GetTrajectoryData,
                std::map<int, mapping::PoseGraphInterface::TrajectoryData>());
   MOCK_METHOD0(constraints, std::vector<Constraint>());
diff --git a/cartographer/mapping/pose_graph_interface.h b/cartographer/mapping/pose_graph_interface.h
index f3d4587..03fe1c9 100644
--- a/cartographer/mapping/pose_graph_interface.h
+++ b/cartographer/mapping/pose_graph_interface.h
@@ -111,6 +111,9 @@ class PoseGraphInterface {
   // Checks if the given trajectory is finished.
   virtual bool IsTrajectoryFinished(int trajectory_id) = 0;
 
+  // Checks if the given trajectory is frozen.
+  virtual bool IsTrajectoryFrozen(int trajectory_id) = 0;
+
   // Returns the trajectory data.
   virtual std::map<int, TrajectoryData> GetTrajectoryData() = 0;