From 440fd322a58fd9b754a1cb76ff45223f98d7f0f7 Mon Sep 17 00:00:00 2001
From: Sijia Wang <wangsijia0628@gmail.com>
Date: Tue, 16 Jun 2026 15:36:00 -0400
Subject: [PATCH 1/2] take segmentation from model setting

---
 activitysim/abm/tables/shadow_pricing.py | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/activitysim/abm/tables/shadow_pricing.py b/activitysim/abm/tables/shadow_pricing.py
index 04c5eafc21..ee7c13ed62 100644
--- a/activitysim/abm/tables/shadow_pricing.py
+++ b/activitysim/abm/tables/shadow_pricing.py
@@ -176,6 +176,7 @@ def __init__(
         )
 
         self.model_selector = model_settings.MODEL_SELECTOR
+        self.chooser_segment_column = model_settings.CHOOSER_SEGMENT_COLUMN_NAME
 
         if (self.num_processes > 1) and not state.settings.fail_fast:
             # if we are multiprocessing, then fail_fast should be true or we will wait forever for failed processes
@@ -826,9 +827,24 @@ def update_shadow_prices(self, state):
             sampled_persons = pd.DataFrame()
             persons_merged = state.get_dataframe("persons_merged")
 
-            # need to join the segment to the choices to sample correct persons
-            segment_to_name_dict = self.shadow_settings.SEGMENT_TO_NAME
-            segment_name = segment_to_name_dict[self.model_selector]
+            # Use the model chooser segmentation to keep shadow-pricing resampling
+            # consistent with segment_ids in location choice settings.
+            segment_name = self.chooser_segment_column
+            if segment_name not in persons_merged.columns:
+                raise SystemConfigurationError(
+                    f"Missing chooser segment column '{segment_name}' in persons_merged "
+                    f"for {self.model_selector} simulation shadow pricing"
+                )
+
+            # Fail fast on obvious misconfiguration instead of silently sampling no one.
+            segment_values = set(self.segment_ids.values())
+            chooser_values = set(persons_merged[segment_name].dropna().unique())
+            if not segment_values.intersection(chooser_values):
+                raise SystemConfigurationError(
+                    f"No overlap between SEGMENT_IDS values ({sorted(segment_values)}) and "
+                    f"persons_merged['{segment_name}'] values for {self.model_selector} "
+                    "simulation shadow pricing"
+                )
 
             if type(self.choices_synced) != pd.DataFrame:
                 self.choices_synced = self.choices_synced.to_frame()

From f82f6e152b33583ec114e207e607fa0bbccf4d51 Mon Sep 17 00:00:00 2001
From: Sijia Wang <wangsijia0628@gmail.com>
Date: Tue, 16 Jun 2026 16:38:32 -0400
Subject: [PATCH 2/2] deprecate `SEGMENT_TO_NAME`

---
 activitysim/abm/tables/shadow_pricing.py | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/activitysim/abm/tables/shadow_pricing.py b/activitysim/abm/tables/shadow_pricing.py
index ee7c13ed62..0cfe1f081d 100644
--- a/activitysim/abm/tables/shadow_pricing.py
+++ b/activitysim/abm/tables/shadow_pricing.py
@@ -62,12 +62,6 @@
 TALLY_CHECKOUT = (1, -1)
 TALLY_PENDING_PERSONS = (2, -1)
 
-default_segment_to_name_dict = {
-    # model_selector : persons_segment_name
-    "school": "school_segment",
-    "workplace": "income_segment",
-}
-
 
 def size_table_name(model_selector):
     """
@@ -134,12 +128,6 @@ class ShadowPriceSettings(PydanticReadable, extra="forbid"):
 
     WRITE_ITERATION_CHOICES: bool = False
 
-    SEGMENT_TO_NAME: dict[str, str] = {
-        "school": "school_segment",
-        "workplace": "income_segment",
-    }  # pydantic uses deep copy, so mutable default value is ok here
-    """Mapping from model_selector to persons_segment_name."""
-
 
 class ShadowPriceCalculator:
     def __init__(