diff --git a/configs/resident/accessibility.yaml b/configs/resident/accessibility.yaml
index 927af56..4ec3209 100644
--- a/configs/resident/accessibility.yaml
+++ b/configs/resident/accessibility.yaml
@@ -11,3 +11,5 @@ CONSTANTS:
   maximum_walk_distance: 3.0
   # perceived minute of in-vehicle time for every minute of out-of-vehicle time
   out_of_vehicle_time_weight: 2.0
+
+explicit_chunk: 812  # 24333 zones in 30 chunks
diff --git a/exercise.py b/exercise.py
index d0c4d7c..1ed78db 100644
--- a/exercise.py
+++ b/exercise.py
@@ -149,4 +149,5 @@ def main(**settings):
         sharrow="require",
         recode_pipeline_columns=True,
         memory_profile=True,
+        chunk_training_mode="explicit",
     )