From 8f132991caefe952c3bb3b7bf7fa173a7df99a6a Mon Sep 17 00:00:00 2001
From: asiripanich <17020181+asiripanich@users.noreply.github.com>
Date: Thu, 30 Oct 2025 12:46:00 +1100
Subject: [PATCH 1/3] fix(jtp): Correct the participant_num assignment logic
 for estimation mode in joint tour participation

---
 .../abm/models/joint_tour_participation.py    | 24 ++++++++++++-------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/activitysim/abm/models/joint_tour_participation.py b/activitysim/abm/models/joint_tour_participation.py
index 47bc2b8ff..528fef643 100644
--- a/activitysim/abm/models/joint_tour_participation.py
+++ b/activitysim/abm/models/joint_tour_participation.py
@@ -451,14 +451,22 @@ def joint_tour_participation(
     PARTICIPANT_COLS = ["tour_id", "household_id", "person_id"]
     participants = candidates[participate][PARTICIPANT_COLS].copy()
 
-    # assign participant_num
-    # FIXME do we want something smarter than the participant with the lowest person_id?
-    participants["participant_num"] = (
-        participants.sort_values(by=["tour_id", "person_id"])
-        .groupby("tour_id")
-        .cumcount()
-        + 1
-    )
+    if estimator:
+        # In estimation mode, use participant_num from survey data to preserve consistency
+        # with the original survey data. ActivitySim treats participant_num=1 as the tour
+        # leader, so the joint tour in the tour table will be associated with the tour
+        # leader's person_id. We merge participant_num from survey data using the
+        # participant_id as the join key to ensure the correct tour leader is identified.
+        participants["participant_num"] = survey_participants_df.reindex(participants.index)["participant_num"]
+    else:
+        # assign participant_num
+        # FIXME do we want something smarter than the participant with the lowest person_id?
+        participants["participant_num"] = (
+            participants.sort_values(by=["tour_id", "person_id"])
+            .groupby("tour_id")
+            .cumcount()
+            + 1
+        )
 
     state.add_table("joint_tour_participants", participants)
 

From 2e7629e6d52120b22f45f1dcec23f0ba34b0a061 Mon Sep 17 00:00:00 2001
From: asiripanich <17020181+asiripanich@users.noreply.github.com>
Date: Thu, 30 Oct 2025 12:46:44 +1100
Subject: [PATCH 2/3] fix(jtf): Handle missing PNUM column by selecting the
 first person in the household

---
 activitysim/abm/models/joint_tour_frequency.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/activitysim/abm/models/joint_tour_frequency.py b/activitysim/abm/models/joint_tour_frequency.py
index cace98d7d..d2dc67bc8 100644
--- a/activitysim/abm/models/joint_tour_frequency.py
+++ b/activitysim/abm/models/joint_tour_frequency.py
@@ -137,7 +137,15 @@ def joint_tour_frequency(
     # - but we don't know the tour participants yet
     # - so we arbitrarily choose the first person in the household
     # - to be point person for the purpose of generating an index and setting origin
-    temp_point_persons = persons.loc[persons.PNUM == 1]
+    if "PNUM" in persons.columns:
+        temp_point_persons = persons.loc[persons.PNUM == 1]
+    else:
+        # if PNUM is not available, we can still get the first person in the household
+        temp_point_persons = (
+            persons.sort_index()  # ensure stable ordering
+            .groupby("household_id", as_index=False)
+            .first()
+        )
     temp_point_persons["person_id"] = temp_point_persons.index
     temp_point_persons = temp_point_persons.set_index("household_id")
     temp_point_persons = temp_point_persons[["person_id", "home_zone_id"]]

From 9028f670516b800edaa4a87f4f4cde8f38a95327 Mon Sep 17 00:00:00 2001
From: asiripanich <17020181+asiripanich@users.noreply.github.com>
Date: Thu, 30 Oct 2025 12:56:48 +1100
Subject: [PATCH 3/3] style: blacken

---
 activitysim/abm/models/joint_tour_participation.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/activitysim/abm/models/joint_tour_participation.py b/activitysim/abm/models/joint_tour_participation.py
index 528fef643..2e5ec618d 100644
--- a/activitysim/abm/models/joint_tour_participation.py
+++ b/activitysim/abm/models/joint_tour_participation.py
@@ -457,7 +457,9 @@ def joint_tour_participation(
         # leader, so the joint tour in the tour table will be associated with the tour
         # leader's person_id. We merge participant_num from survey data using the
         # participant_id as the join key to ensure the correct tour leader is identified.
-        participants["participant_num"] = survey_participants_df.reindex(participants.index)["participant_num"]
+        participants["participant_num"] = survey_participants_df.reindex(
+            participants.index
+        )["participant_num"]
     else:
         # assign participant_num
         # FIXME do we want something smarter than the participant with the lowest person_id?