diff --git a/map/traffic_manager.cpp b/map/traffic_manager.cpp
index eabbdfbbc..d6ba95c05 100644
--- a/map/traffic_manager.cpp
+++ b/map/traffic_manager.cpp
@@ -404,8 +404,7 @@ void TrafficManager::InitializeDataSources(std::vector<FrozenDataSource> & dataS
  * If we batch-decode segments, we need to fix the [partner] segment IDs in the segment and path
  * structures to accept a TraFF message ID (string) rather than an integer.
  */
-void TrafficManager::DecodeMessage(traffxml::TraffMessage & message, std::map<MwmSet::MwmId,
-                                   traffic::TrafficInfo::Coloring> & trafficCache)
+void TrafficManager::DecodeMessage(traffxml::TraffMessage & message)
 {
   if (message.m_location)
   {
@@ -503,7 +502,7 @@ void TrafficManager::DecodeMessage(traffxml::TraffMessage & message, std::map<Mw
              */
           }
           // TODO process all TrafficImpact fields and determine the speed group based on that
-          trafficCache[paths[i].m_path[j].GetFeatureId().m_mwmId][traffic::TrafficInfo::RoadSegmentId(fid, segment, direction)] = sg;
+          message.m_decoded[paths[i].m_path[j].GetFeatureId().m_mwmId][traffic::TrafficInfo::RoadSegmentId(fid, segment, direction)] = sg;
         }
     }
   }
@@ -555,7 +554,10 @@ void TrafficManager::ThreadRoutine()
     for (auto [id, message] : m_messageCache)
     {
       LOG(LINFO, (" ", id, ":", message));
-      DecodeMessage(message, allMwmColoring);
+      DecodeMessage(message);
+      // store message coloring in AllMwmColoring
+      // TODO do this in a later pass...?
+      traffxml::MergeMultiMwmColoring(message.m_decoded, allMwmColoring);
     }
 
     // set new coloring for MWMs
diff --git a/traffxml/CMakeLists.txt b/traffxml/CMakeLists.txt
index 418c7e15f..e8deb4902 100644
--- a/traffxml/CMakeLists.txt
+++ b/traffxml/CMakeLists.txt
@@ -13,4 +13,5 @@ omim_add_library(${PROJECT_NAME} ${SRC})
 
 target_link_libraries(${PROJECT_NAME}
   pugixml
+  coding
 )
diff --git a/traffxml/traff_model.cpp b/traffxml/traff_model.cpp
index f6e4715b9..f61b07adf 100644
--- a/traffxml/traff_model.cpp
+++ b/traffxml/traff_model.cpp
@@ -268,6 +268,30 @@ uint32_t GuessDnp(openlr::LocationReferencePoint & p1, openlr::LocationReference
   return doe * 1.19f + 0.5f;
 }
 
+void MergeMultiMwmColoring(MultiMwmColoring & delta, MultiMwmColoring & target)
+{
+  // for each mwm in delta
+  for (auto [mwmId, coloring] : delta)
+    // if target contains mwm
+    if (auto target_it = target.find(mwmId); target_it != target.end())
+      // for each segment in delta[mwm] (coloring)
+      for (auto [rsid, sg] : coloring)
+        // if target[mwm] contains segment
+        if (auto c_it = target_it->second.find(rsid) ; c_it != target_it->second.end())
+        {
+          // if delta overrules target (target is Unknown, delta is TempBlock or delta is slower than target)
+          if ((sg == traffic::SpeedGroup::TempBlock)
+              || (c_it->second == traffic::SpeedGroup::Unknown) || (sg < c_it->second))
+            target_it->second[rsid] = sg;
+        }
+        else
+          // if target[mwm] does not contain segment, add speed group
+          target_it->second[rsid] = sg;
+    else
+      // if target does not contain mwm, add coloring
+      target[mwmId] = coloring;
+}
+
 /*
 string DebugPrint(LinearSegmentSource source)
 {
diff --git a/traffxml/traff_model.hpp b/traffxml/traff_model.hpp
index 3e8fd539f..436f99966 100644
--- a/traffxml/traff_model.hpp
+++ b/traffxml/traff_model.hpp
@@ -5,10 +5,14 @@
 #include "geometry/latlon.hpp"
 #include "geometry/point2d.hpp"
 
+#include "indexer/mwm_set.hpp"
+
 #include "openlr/openlr_model.hpp"
 
 #include "traffic/speed_groups.hpp"
+#include "traffic/traffic_info.hpp"
 
+#include <map>
 #include <string>
 #include <vector>
 
@@ -271,6 +275,11 @@ struct TraffEvent
   // TODO supplementary information
 };
 
+/**
+ * @brief Global mapping from feature segments to speed groups, across all MWMs.
+ */
+using MultiMwmColoring = std::map<MwmSet::MwmId, std::map<traffic::TrafficInfo::RoadSegmentId, traffic::SpeedGroup>>;
+
 struct TraffMessage
 {
   /**
@@ -299,6 +308,7 @@ struct TraffMessage
   std::optional<TraffLocation> m_location;
   std::vector<TraffEvent> m_events;
   std::vector<std::string> m_replaces;
+  MultiMwmColoring m_decoded;
 };
 
 using TraffFeed = std::vector<TraffMessage>;
@@ -317,6 +327,21 @@ using TraffFeed = std::vector<TraffMessage>;
  */
 uint32_t GuessDnp(openlr::LocationReferencePoint & p1, openlr::LocationReferencePoint & p2);
 
+/**
+ * @brief Merges the contents of one `MultiMwmColoring` into another.
+ *
+ * After this function returns, `target` will hold the union of the entries it had prior to the
+ * function call and the entries from `delta`.
+ *
+ * In case of conflict, the more restrictive speed group wins. That is, `TempBlock` overrides
+ * everything else, `Unknown` never overrides anything else, and among `G0` to `G5`, the lowest
+ * group wins.
+ *
+ * @param delta Contains the entries to be added.
+ * @param target Receives the added entries.
+ */
+void MergeMultiMwmColoring(MultiMwmColoring &delta, MultiMwmColoring & target);
+
 std::string DebugPrint(IsoTime time);
 std::string DebugPrint(Directionality directionality);
 std::string DebugPrint(Ramps ramps);