diff --git a/activitysim/abm/models/vehicle_allocation.py b/activitysim/abm/models/vehicle_allocation.py
index e4129e106..a341493ff 100644
--- a/activitysim/abm/models/vehicle_allocation.py
+++ b/activitysim/abm/models/vehicle_allocation.py
@@ -196,6 +196,17 @@ def vehicle_allocation(
     choosers = pd.merge(choosers, vehicles_wide, how="left", on="household_id")
     choosers.set_index("tour_id", inplace=True)
 
+    ## get categorical dtype for vehicle_type and use it to create new dtype for
+    ## vehicle_occup_* and selected_vehicle columns
+    veh_type_dtype = vehicles["vehicle_type"].dtype
+    if isinstance(veh_type_dtype, pd.CategoricalDtype):
+        veh_categories = list(veh_type_dtype.categories)
+        if "non_hh_veh" not in veh_categories:
+            veh_categories.append("non_hh_veh")
+        veh_choice_dtype = pd.CategoricalDtype(veh_categories, ordered=False)
+    else:
+        veh_choice_dtype = "category"
+
     # ----- setup skim keys
     skims = get_skim_dict(network_los, choosers)
     locals_dict.update(skims)
@@ -254,7 +265,7 @@ def vehicle_allocation(
         # creating a column for choice of each occupancy level
         tours_veh_occup_col = f"vehicle_occup_{occup}"
         tours[tours_veh_occup_col] = choices["choice"]
-        tours[tours_veh_occup_col] = tours[tours_veh_occup_col].astype("category")
+        tours[tours_veh_occup_col] = tours[tours_veh_occup_col].astype(veh_choice_dtype)
         tours_veh_occup_cols.append(tours_veh_occup_col)
 
     if estimator:
diff --git a/activitysim/abm/models/vehicle_type_choice.py b/activitysim/abm/models/vehicle_type_choice.py
index 8271ac6e8..813652459 100644
--- a/activitysim/abm/models/vehicle_type_choice.py
+++ b/activitysim/abm/models/vehicle_type_choice.py
@@ -393,7 +393,7 @@ def iterate_vehicle_type_choice(
             sorted(alts_cats_dict["fuel_type"]), ordered=False
         )
         vehicle_type_cat = pd.api.types.CategoricalDtype(
-            [""] + sorted(set(alts_wide["vehicle_type"])), ordered=False
+            sorted(set(alts_wide["vehicle_type"])), ordered=False
         )
 
         alts_wide["body_type"] = alts_wide["body_type"].astype(body_type_cat)
@@ -403,7 +403,7 @@ def iterate_vehicle_type_choice(
         alts_wide = alts_long = None
         alts = model_spec.columns
         vehicle_type_cat = pd.api.types.CategoricalDtype(
-            [""] + sorted(set(alts)), ordered=False
+            sorted(set(alts)), ordered=False
         )
 
     # alts preprocessor