diff --git a/activitysim/abm/models/__init__.py b/activitysim/abm/models/__init__.py
index c98063af80..a855f1ca74 100644
--- a/activitysim/abm/models/__init__.py
+++ b/activitysim/abm/models/__init__.py
@@ -27,3 +27,4 @@
 from . import trip_purpose
 from . import trip_purpose_and_destination
 from . import trip_scheduling
+from . import trip_matrices
diff --git a/activitysim/abm/models/trip_matrices.py b/activitysim/abm/models/trip_matrices.py
new file mode 100644
index 0000000000..baee44aba2
--- /dev/null
+++ b/activitysim/abm/models/trip_matrices.py
@@ -0,0 +1,147 @@
+# ActivitySim
+# See full license in LICENSE.txt.
+
+import logging
+
+import openmatrix as omx
+import pandas as pd
+import numpy as np
+
+from activitysim.core import config
+from activitysim.core import inject
+from activitysim.core import pipeline
+
+from .util import expressions
+from .util.expressions import skim_time_period_label
+
+logger = logging.getLogger(__name__)
+
+
+@inject.step()
+def write_trip_matrices(trips, skim_dict, skim_stack):
+    """
+    Write trip matrices step.
+
+    Adds boolean columns to local trips table via annotation expressions,
+    then aggregates trip counts and writes OD matrices to OMX.  Save annotated
+    trips table to pipeline if desired.
+    """
+
+    model_settings = config.read_model_settings('write_trip_matrices.yaml')
+    trips_df = annotate_trips(trips, skim_dict, skim_stack, model_settings)
+
+    if bool(model_settings.get('SAVE_TRIPS_TABLE')):
+        pipeline.replace_table('trips', trips_df)
+
+    logger.info('Aggregating trips...')
+    aggregate_trips = trips_df.groupby(['origin', 'destination'], sort=False).sum()
+    logger.info('Finished.')
+
+    orig_vals = aggregate_trips.index.get_level_values('origin')
+    dest_vals = aggregate_trips.index.get_level_values('destination')
+
+    zone_index = pipeline.get_table('land_use').index
+    assert all(zone in zone_index for zone in orig_vals)
+    assert all(zone in zone_index for zone in dest_vals)
+
+    _, orig_index = zone_index.reindex(orig_vals)
+    _, dest_index = zone_index.reindex(dest_vals)
+
+    write_matrices(aggregate_trips, zone_index, orig_index, dest_index, model_settings)
+
+
+def annotate_trips(trips, skim_dict, skim_stack, model_settings):
+    """
+    Add columns to local trips table. The annotator has
+    access to the origin/destination skims and everything
+    defined in the model settings CONSTANTS.
+
+    Pipeline tables can also be accessed by listing them under
+    TABLES in the preprocessor settings.
+    """
+
+    trips_df = trips.to_frame()
+
+    trace_label = 'trip_matrices'
+
+    # setup skim keys
+    assert ('trip_period' not in trips_df)
+    trips_df['trip_period'] = skim_time_period_label(trips_df.depart)
+    od_skim_wrapper = skim_dict.wrap('origin', 'destination')
+    odt_skim_stack_wrapper = skim_stack.wrap(left_key='origin', right_key='destination',
+                                             skim_key='trip_period')
+    skims = {
+        'od_skims': od_skim_wrapper,
+        "odt_skims": odt_skim_stack_wrapper
+    }
+
+    locals_dict = {}
+    constants = config.get_model_constants(model_settings)
+    if constants is not None:
+        locals_dict.update(constants)
+
+    expressions.annotate_preprocessors(
+        trips_df, locals_dict, skims,
+        model_settings, trace_label)
+
+    # Data will be expanded by an expansion weight column from
+    # the households pipeline table, if specified in the model settings.
+    hh_weight_col = model_settings.get('HH_EXPANSION_WEIGHT_COL')
+
+    if hh_weight_col and hh_weight_col not in trips_df:
+        logger.info("adding '%s' from households to trips table" % hh_weight_col)
+        household_weights = pipeline.get_table('households')[hh_weight_col]
+        trips_df[hh_weight_col] = trips_df.household_id.map(household_weights)
+
+    return trips_df
+
+
+def write_matrices(aggregate_trips, zone_index, orig_index, dest_index, model_settings):
+    """
+    Write aggregated trips to OMX format.
+
+    The MATRICES setting lists the new OMX files to write.
+    Each file can contain any number of 'tables', each specified by a
+    table key ('name') and a trips table column ('data_field') to use
+    for aggregated counts.
+
+    Any data type may be used for columns added in the annotation phase,
+    but the table 'data_field's must be summable types: ints, floats, bools.
+    """
+
+    matrix_settings = model_settings.get('MATRICES')
+
+    if not matrix_settings:
+        logger.error('Missing MATRICES setting in write_trip_matrices.yaml')
+
+    for matrix in matrix_settings:
+        filename = matrix.get('file_name')
+        filepath = config.output_file_path(filename)
+        logger.info('opening %s' % filepath)
+        file = omx.open_file(filepath, 'w')  # possibly overwrite existing file
+        table_settings = matrix.get('tables')
+
+        for table in table_settings:
+            table_name = table.get('name')
+            col = table.get('data_field')
+
+            if col not in aggregate_trips:
+                logger.error('missing %s column in %s DataFrame' % (col, aggregate_trips.name))
+                return
+
+            hh_weight_col = model_settings.get('HH_EXPANSION_WEIGHT_COL')
+            if hh_weight_col:
+                aggregate_trips[col] = aggregate_trips[col] / aggregate_trips[hh_weight_col]
+
+            data = np.zeros((len(zone_index), len(zone_index)))
+            data[orig_index, dest_index] = aggregate_trips[col]
+            logger.info('writing %s' % table_name)
+            file[table_name] = data  # write to file
+
+        # include the index-to-zone map in the file
+        logger.info('adding %s mapping for %s zones to %s' %
+                    (zone_index.name, zone_index.size, filename))
+        file.create_mapping(zone_index.name, zone_index.to_numpy())
+
+        logger.info('closing %s' % filepath)
+        file.close()
diff --git a/activitysim/abm/models/trip_scheduling.py b/activitysim/abm/models/trip_scheduling.py
index 3ca4b890fd..ae63101a23 100644
--- a/activitysim/abm/models/trip_scheduling.py
+++ b/activitysim/abm/models/trip_scheduling.py
@@ -319,7 +319,7 @@ def schedule_trips_in_leg(
     trips = trips.sort_index()
     trips['next_trip_id'] = np.roll(trips.index, -1 if outbound else 1)
     is_final = (trips.trip_num == trips.trip_count) if outbound else (trips.trip_num == 1)
-    trips.next_trip_id = trips.next_trip_id.where(is_final, NO_TRIP_ID)
+    trips.next_trip_id = trips.next_trip_id.where(~is_final, NO_TRIP_ID)
 
     # iterate over outbound trips in ascending trip_num order, skipping the initial trip
     # iterate over inbound trips in descending trip_num order, skipping the finial trip
diff --git a/activitysim/abm/tables/households.py b/activitysim/abm/tables/households.py
index 86c3a21120..6bfc308aa3 100644
--- a/activitysim/abm/tables/households.py
+++ b/activitysim/abm/tables/households.py
@@ -20,9 +20,11 @@
 def households(households_sample_size, override_hh_ids, trace_hh_id):
 
     df_full = read_input_table("households")
-    households_sliced = False
+    tot_households = df_full.shape[0]
+
+    logger.info("full household list contains %s households" % tot_households)
 
-    logger.info("full household list contains %s households" % df_full.shape[0])
+    households_sliced = False
 
     # only using households listed in override_hh_ids
     if override_hh_ids is not None:
@@ -48,9 +50,9 @@ def households(households_sample_size, override_hh_ids, trace_hh_id):
         households_sliced = True
 
     # if we need a subset of full store
-    elif households_sample_size > 0 and df_full.shape[0] > households_sample_size:
+    elif tot_households > households_sample_size > 0:
 
-        logger.info("sampling %s of %s households" % (households_sample_size, df_full.shape[0]))
+        logger.info("sampling %s of %s households" % (households_sample_size, tot_households))
 
         """
         Because random seed is set differently for each step, sampling of households using
@@ -80,6 +82,14 @@ def households(households_sample_size, override_hh_ids, trace_hh_id):
     # persons table
     inject.add_injectable('households_sliced', households_sliced)
 
+    if 'sample_rate' not in df.columns:
+        if households_sample_size == 0:
+            sample_rate = 1
+        else:
+            sample_rate = round(households_sample_size / tot_households, 3)
+
+        df['sample_rate'] = sample_rate
+
     logger.info("loaded households %s" % (df.shape,))
 
     # FIXME - pathological knowledge of name of chunk_id column used by chunked_choosers_by_chunk_id
diff --git a/activitysim/abm/test/test_pipeline.py b/activitysim/abm/test/test_pipeline.py
index 1698561b00..9a04c89380 100644
--- a/activitysim/abm/test/test_pipeline.py
+++ b/activitysim/abm/test/test_pipeline.py
@@ -4,8 +4,12 @@
 import logging
 import pkg_resources
 
+import openmatrix as omx
+import numpy as np
+import numpy.testing as npt
+
 import pandas as pd
-import pandas.util.testing as pdt
+import pandas.testing as pdt
 import pytest
 import yaml
 
@@ -17,6 +21,7 @@
 
 # set the max households for all tests (this is to limit memory use on travis)
 HOUSEHOLDS_SAMPLE_SIZE = 100
+HOUSEHOLDS_SAMPLE_RATE = 0.02  # HOUSEHOLDS_SAMPLE_RATE / 5000 households
 
 # household with mandatory, non mandatory, atwork_subtours, and joint tours
 HH_ID = 257341
@@ -52,6 +57,7 @@ def setup_dirs(configs_dir, data_dir=None):
     tracing.delete_output_files('csv')
     tracing.delete_output_files('txt')
     tracing.delete_output_files('yaml')
+    tracing.delete_output_files('omx')
 
 
 def teardown_function(func):
@@ -433,6 +439,18 @@ def regress():
     # should be at least two tours per trip
     assert trips_df.shape[0] >= 2*tours_df.shape[0]
 
+    # write_trip_matrices
+    trip_matrices_file = config.output_file_path('trips_md.omx')
+    assert os.path.exists(trip_matrices_file)
+    trip_matrices = omx.open_file(trip_matrices_file)
+    assert trip_matrices.shape() == (25, 25)
+
+    assert 'WALK_MD' in trip_matrices.list_matrices()
+    walk_trips = np.array(trip_matrices['WALK_MD'])
+    assert walk_trips.dtype == np.dtype('float64')
+
+    trip_matrices.close()
+
 
 def test_full_run1():
 
@@ -517,6 +535,7 @@ def test_full_run5_singleton():
 
 if __name__ == "__main__":
 
+    from activitysim import abm  # register injectables
     print("running test_full_run1")
     test_full_run1()
     # teardown_function(None)
diff --git a/activitysim/examples/example_mtc/configs/settings.yaml b/activitysim/examples/example_mtc/configs/settings.yaml
index 9010a163c2..fd688b94b0 100644
--- a/activitysim/examples/example_mtc/configs/settings.yaml
+++ b/activitysim/examples/example_mtc/configs/settings.yaml
@@ -86,6 +86,7 @@ models:
   - trip_mode_choice
   - write_data_dictionary
   - track_skim_usage
+  - write_trip_matrices
   - write_tables
 
 # to resume after last successful checkpoint, specify resume_after: _
diff --git a/activitysim/examples/example_mtc/configs/write_trip_matrices.yaml b/activitysim/examples/example_mtc/configs/write_trip_matrices.yaml
new file mode 100644
index 0000000000..6059d750e9
--- /dev/null
+++ b/activitysim/examples/example_mtc/configs/write_trip_matrices.yaml
@@ -0,0 +1,274 @@
+# read trips table post preprocessor and run expressions to code
+# additional data fields, with one data fields for each matrix specified below
+
+preprocessor:
+  SPEC: write_trip_matrices_annotate_trips_preprocessor
+  DF: trips
+  TABLES:
+    - tours
+
+# divide trip counts by household expansion factor
+HH_EXPANSION_WEIGHT_COL: sample_rate  # added when households read in
+
+# save preprocessed trips table to pipeline if desired
+SAVE_TRIPS_TABLE: False
+
+MATRICES:
+  - file_name: trips_ea.omx
+    tables:
+      - name: DRIVEALONEFREE_EA
+        data_field: DRIVEALONEFREE_EA
+      - name: DRIVEALONEPAY_EA
+        data_field: DRIVEALONEPAY_EA
+      - name: SHARED2FREE_EA
+        data_field: SHARED2FREE_EA
+      - name: SHARED2PAY_EA
+        data_field: SHARED2PAY_EA
+      - name: SHARED3FREE_EA
+        data_field: SHARED3FREE_EA
+      - name: SHARED3PAY_EA
+        data_field: SHARED3PAY_EA
+      - name: WALK_EA
+        data_field: WALK_EA
+      - name: BIKE_EA
+        data_field: BIKE_EA
+      - name: WALK_LOC_WALK_EA
+        data_field: WALK_LOC_WALK_EA
+      - name: WALK_LRF_WALK_EA
+        data_field: WALK_LRF_WALK_EA
+      - name: WALK_EXP_WALK_EA
+        data_field: WALK_EXP_WALK_EA
+      - name: WALK_HVY_WALK_EA
+        data_field: WALK_HVY_WALK_EA
+      - name: WALK_COM_WALK_EA
+        data_field: WALK_COM_WALK_EA
+      - name: DRIVE_LOC_WALK_EA
+        data_field: DRIVE_LOC_WALK_EA
+      - name: DRIVE_LRF_WALK_EA
+        data_field: DRIVE_LRF_WALK_EA
+      - name: DRIVE_EXP_WALK_EA
+        data_field: DRIVE_EXP_WALK_EA
+      - name: DRIVE_HVY_WALK_EA
+        data_field: DRIVE_HVY_WALK_EA
+      - name: DRIVE_COM_WALK_EA
+        data_field: DRIVE_COM_WALK_EA
+      - name: WALK_LOC_DRIVE_EA
+        data_field: WALK_LOC_DRIVE_EA
+      - name: WALK_LRF_DRIVE_EA
+        data_field: WALK_LRF_DRIVE_EA
+      - name: WALK_EXP_DRIVE_EA
+        data_field: WALK_EXP_DRIVE_EA
+      - name: WALK_DRIVE_HVY_EA
+        data_field: WALK_DRIVE_HVY_EA
+      - name: WALK_COM_DRIVE_EA
+        data_field: WALK_COM_DRIVE_EA
+  - file_name: trips_am.omx
+    tables:
+      - name: DRIVEALONEFREE_AM
+        data_field: DRIVEALONEFREE_AM
+      - name: DRIVEALONEPAY_AM
+        data_field: DRIVEALONEPAY_AM
+      - name: SHARED2FREE_AM
+        data_field: SHARED2FREE_AM
+      - name: SHARED2PAY_AM
+        data_field: SHARED2PAY_AM
+      - name: SHARED3FREE_AM
+        data_field: SHARED3FREE_AM
+      - name: SHARED3PAY_AM
+        data_field: SHARED3PAY_AM
+      - name: WALK_AM
+        data_field: WALK_AM
+      - name: BIKE_AM
+        data_field: BIKE_AM
+      - name: WALK_LOC_WALK_AM
+        data_field: WALK_LOC_WALK_AM
+      - name: WALK_LRF_WALK_AM
+        data_field: WALK_LRF_WALK_AM
+      - name: WALK_EXP_WALK_AM
+        data_field: WALK_EXP_WALK_AM
+      - name: WALK_HVY_WALK_AM
+        data_field: WALK_HVY_WALK_AM
+      - name: WALK_COM_WALK_AM
+        data_field: WALK_COM_WALK_AM
+      - name: DRIVE_LOC_WALK_AM
+        data_field: DRIVE_LOC_WALK_AM
+      - name: DRIVE_LRF_WALK_AM
+        data_field: DRIVE_LRF_WALK_AM
+      - name: DRIVE_EXP_WALK_AM
+        data_field: DRIVE_EXP_WALK_AM
+      - name: DRIVE_HVY_WALK_AM
+        data_field: DRIVE_HVY_WALK_AM
+      - name: DRIVE_COM_WALK_AM
+        data_field: DRIVE_COM_WALK_AM
+      - name: WALK_LOC_DRIVE_AM
+        data_field: WALK_LOC_DRIVE_AM
+      - name: WALK_LRF_DRIVE_AM
+        data_field: WALK_LRF_DRIVE_AM
+      - name: WALK_EXP_DRIVE_AM
+        data_field: WALK_EXP_DRIVE_AM
+      - name: WALK_DRIVE_HVY_AM
+        data_field: WALK_DRIVE_HVY_AM
+      - name: WALK_COM_DRIVE_AM
+        data_field: WALK_COM_DRIVE_AM
+  - file_name: trips_md.omx
+    tables:
+      - name: DRIVEALONEFREE_MD
+        data_field: DRIVEALONEFREE_MD
+      - name: DRIVEALONEPAY_MD
+        data_field: DRIVEALONEPAY_MD
+      - name: SHARED2FREE_MD
+        data_field: SHARED2FREE_MD
+      - name: SHARED2PAY_MD
+        data_field: SHARED2PAY_MD
+      - name: SHARED3FREE_MD
+        data_field: SHARED3FREE_MD
+      - name: SHARED3PAY_MD
+        data_field: SHARED3PAY_MD
+      - name: WALK_MD
+        data_field: WALK_MD
+      - name: BIKE_MD
+        data_field: BIKE_MD
+      - name: WALK_LOC_WALK_MD
+        data_field: WALK_LOC_WALK_MD
+      - name: WALK_LRF_WALK_MD
+        data_field: WALK_LRF_WALK_MD
+      - name: WALK_EXP_WALK_MD
+        data_field: WALK_EXP_WALK_MD
+      - name: WALK_HVY_WALK_MD
+        data_field: WALK_HVY_WALK_MD
+      - name: WALK_COM_WALK_MD
+        data_field: WALK_COM_WALK_MD
+      - name: DRIVE_LOC_WALK_MD
+        data_field: DRIVE_LOC_WALK_MD
+      - name: DRIVE_LRF_WALK_MD
+        data_field: DRIVE_LRF_WALK_MD
+      - name: DRIVE_EXP_WALK_MD
+        data_field: DRIVE_EXP_WALK_MD
+      - name: DRIVE_HVY_WALK_MD
+        data_field: DRIVE_HVY_WALK_MD
+      - name: DRIVE_COM_WALK_MD
+        data_field: DRIVE_COM_WALK_MD
+      - name: WALK_LOC_DRIVE_MD
+        data_field: WALK_LOC_DRIVE_MD
+      - name: WALK_LRF_DRIVE_MD
+        data_field: WALK_LRF_DRIVE_MD
+      - name: WALK_EXP_DRIVE_MD
+        data_field: WALK_EXP_DRIVE_MD
+      - name: WALK_DRIVE_HVY_MD
+        data_field: WALK_DRIVE_HVY_MD
+      - name: WALK_COM_DRIVE_MD
+        data_field: WALK_COM_DRIVE_MD
+  - file_name: trips_pm.omx
+    tables:
+      - name: DRIVEALONEFREE_PM
+        data_field: DRIVEALONEFREE_PM
+      - name: DRIVEALONEPAY_PM
+        data_field: DRIVEALONEPAY_PM
+      - name: SHARED2FREE_PM
+        data_field: SHARED2FREE_PM
+      - name: SHARED2PAY_PM
+        data_field: SHARED2PAY_PM
+      - name: SHARED3FREE_PM
+        data_field: SHARED3FREE_PM
+      - name: SHARED3PAY_PM
+        data_field: SHARED3PAY_PM
+      - name: WALK_PM
+        data_field: WALK_PM
+      - name: BIKE_PM
+        data_field: BIKE_PM
+      - name: WALK_LOC_WALK_PM
+        data_field: WALK_LOC_WALK_PM
+      - name: WALK_LRF_WALK_PM
+        data_field: WALK_LRF_WALK_PM
+      - name: WALK_EXP_WALK_PM
+        data_field: WALK_EXP_WALK_PM
+      - name: WALK_HVY_WALK_PM
+        data_field: WALK_HVY_WALK_PM
+      - name: WALK_COM_WALK_PM
+        data_field: WALK_COM_WALK_PM
+      - name: DRIVE_LOC_WALK_PM
+        data_field: DRIVE_LOC_WALK_PM
+      - name: DRIVE_LRF_WALK_PM
+        data_field: DRIVE_LRF_WALK_PM
+      - name: DRIVE_EXP_WALK_PM
+        data_field: DRIVE_EXP_WALK_PM
+      - name: DRIVE_HVY_WALK_PM
+        data_field: DRIVE_HVY_WALK_PM
+      - name: DRIVE_COM_WALK_PM
+        data_field: DRIVE_COM_WALK_PM
+      - name: WALK_LOC_DRIVE_PM
+        data_field: WALK_LOC_DRIVE_PM
+      - name: WALK_LRF_DRIVE_PM
+        data_field: WALK_LRF_DRIVE_PM
+      - name: WALK_EXP_DRIVE_PM
+        data_field: WALK_EXP_DRIVE_PM
+      - name: WALK_DRIVE_HVY_PM
+        data_field: WALK_DRIVE_HVY_PM
+      - name: WALK_COM_DRIVE_PM
+        data_field: WALK_COM_DRIVE_PM
+  - file_name: trips_ev.omx
+    tables:
+      - name: DRIVEALONEFREE_EV
+        data_field: DRIVEALONEFREE_EV
+      - name: DRIVEALONEPAY_EV
+        data_field: DRIVEALONEPAY_EV
+      - name: SHARED2FREE_EV
+        data_field: SHARED2FREE_EV
+      - name: SHARED2PAY_EV
+        data_field: SHARED2PAY_EV
+      - name: SHARED3FREE_EV
+        data_field: SHARED3FREE_EV
+      - name: SHARED3PAY_EV
+        data_field: SHARED3PAY_EV
+      - name: WALK_EV
+        data_field: WALK_EV
+      - name: BIKE_EV
+        data_field: BIKE_EV
+      - name: WALK_LOC_WALK_EV
+        data_field: WALK_LOC_WALK_EV
+      - name: WALK_LRF_WALK_EV
+        data_field: WALK_LRF_WALK_EV
+      - name: WALK_EXP_WALK_EV
+        data_field: WALK_EXP_WALK_EV
+      - name: WALK_HVY_WALK_EV
+        data_field: WALK_HVY_WALK_EV
+      - name: WALK_COM_WALK_EV
+        data_field: WALK_COM_WALK_EV
+      - name: DRIVE_LOC_WALK_EV
+        data_field: DRIVE_LOC_WALK_EV
+      - name: DRIVE_LRF_WALK_EV
+        data_field: DRIVE_LRF_WALK_EV
+      - name: DRIVE_EXP_WALK_EV
+        data_field: DRIVE_EXP_WALK_EV
+      - name: DRIVE_HVY_WALK_EV
+        data_field: DRIVE_HVY_WALK_EV
+      - name: DRIVE_COM_WALK_EV
+        data_field: DRIVE_COM_WALK_EV
+      - name: WALK_LOC_DRIVE_EV
+        data_field: WALK_LOC_DRIVE_EV
+      - name: WALK_LRF_DRIVE_EV
+        data_field: WALK_LRF_DRIVE_EV
+      - name: WALK_EXP_DRIVE_EV
+        data_field: WALK_EXP_DRIVE_EV
+      - name: WALK_DRIVE_HVY_EV
+        data_field: WALK_DRIVE_HVY_EV
+      - name: WALK_COM_DRIVE_EV
+        data_field: WALK_COM_DRIVE_EV
+
+CONSTANTS:
+  time_periods:
+    EA:
+      first_hour: 3
+      last_hour: 5
+    AM:
+      first_hour: 6
+      last_hour: 9
+    MD:
+      first_hour: 10
+      last_hour: 14
+    PM:
+      first_hour: 15
+      last_hour: 18
+    EV:
+      first_hour: 19
+      last_hour: 2
diff --git a/activitysim/examples/example_mtc/configs/write_trip_matrices_annotate_trips_preprocessor.csv b/activitysim/examples/example_mtc/configs/write_trip_matrices_annotate_trips_preprocessor.csv
new file mode 100644
index 0000000000..8f3e386e60
--- /dev/null
+++ b/activitysim/examples/example_mtc/configs/write_trip_matrices_annotate_trips_preprocessor.csv
@@ -0,0 +1,130 @@
+Description,Target,Expression
+# add additional fields,,
+,tour_participants,trips.tour_id.map(tours.number_of_participants)
+,distance,od_skims['DIST']
+# code time periods,,
+,is_ea,"trips.depart.between(time_periods['EA']['first_hour'], time_periods['EA']['last_hour'])"
+,is_am,"trips.depart.between(time_periods['AM']['first_hour'], time_periods['AM']['last_hour'])"
+,is_md,"trips.depart.between(time_periods['MD']['first_hour'], time_periods['MD']['last_hour'])"
+,is_pm,"trips.depart.between(time_periods['PM']['first_hour'], time_periods['PM']['last_hour'])"
+,is_ev,(trips.depart >= time_periods['EV']['first_hour']) | (trips.depart <=  time_periods['EV']['last_hour'])
+# ea trips,,
+,DRIVEALONEFREE_EA,((trips.trip_mode == 'DRIVEALONEFREE') & is_ea) * tour_participants
+,DRIVEALONEPAY_EA,((trips.trip_mode == 'DRIVEALONEPAY') & is_ea) * tour_participants
+,SHARED2FREE_EA,((trips.trip_mode == 'SHARED2FREE') & is_ea) * tour_participants
+,SHARED2PAY_EA,((trips.trip_mode == 'SHARED2PAY') & is_ea) * tour_participants
+,SHARED3FREE_EA,((trips.trip_mode == 'SHARED3FREE') & is_ea) * tour_participants
+,SHARED3PAY_EA,((trips.trip_mode == 'SHARED3PAY') & is_ea) * tour_participants
+,WALK_EA,((trips.trip_mode == 'WALK') & is_ea) * tour_participants
+,BIKE_EA,((trips.trip_mode == 'BIKE') & is_ea) * tour_participants
+,WALK_LOC_WALK_EA,((trips.trip_mode == 'WALK_LOC') & is_ea) * tour_participants
+,WALK_LRF_WALK_EA,((trips.trip_mode == 'WALK_LRF') & is_ea) * tour_participants
+,WALK_EXP_WALK_EA,((trips.trip_mode == 'WALK_EXP') & is_ea) * tour_participants
+,WALK_HVY_WALK_EA,((trips.trip_mode == 'WALK_HVY') & is_ea) * tour_participants
+,WALK_COM_WALK_EA,((trips.trip_mode == 'WALK_COM') & is_ea) * tour_participants
+,DRIVE_LOC_WALK_EA,((trips.trip_mode == 'DRIVE_LOC') & is_ea & trips.outbound) * tour_participants
+,DRIVE_LRF_WALK_EA,((trips.trip_mode == 'DRIVE_LRF') & is_ea & trips.outbound) * tour_participants
+,DRIVE_EXP_WALK_EA,((trips.trip_mode == 'DRIVE_EXP') & is_ea & trips.outbound) * tour_participants
+,DRIVE_HVY_WALK_EA,((trips.trip_mode == 'DRIVE_HVY') & is_ea & trips.outbound) * tour_participants
+,DRIVE_COM_WALK_EA,((trips.trip_mode == 'DRIVE_COM') & is_ea & trips.outbound) * tour_participants
+,WALK_LOC_DRIVE_EA,((trips.trip_mode == 'DRIVE_LOC') & is_ea & ~trips.outbound) * tour_participants
+,WALK_LRF_DRIVE_EA,((trips.trip_mode == 'DRIVE_LRF') & is_ea & ~trips.outbound) * tour_participants
+,WALK_EXP_DRIVE_EA,((trips.trip_mode == 'DRIVE_EXP') & is_ea & ~trips.outbound) * tour_participants
+,WALK_DRIVE_HVY_EA,((trips.trip_mode == 'DRIVE_HVY') & is_ea & ~trips.outbound) * tour_participants
+,WALK_COM_DRIVE_EA,((trips.trip_mode == 'DRIVE_COM') & is_ea & ~trips.outbound) * tour_participants
+# am trips,,
+,DRIVEALONEFREE_AM,((trips.trip_mode == 'DRIVEALONEFREE') & is_am) * tour_participants
+,DRIVEALONEPAY_AM,((trips.trip_mode == 'DRIVEALONEPAY') & is_am) * tour_participants
+,SHARED2FREE_AM,((trips.trip_mode == 'SHARED2FREE') & is_am) * tour_participants
+,SHARED2PAY_AM,((trips.trip_mode == 'SHARED2PAY') & is_am) * tour_participants
+,SHARED3FREE_AM,((trips.trip_mode == 'SHARED3FREE') & is_am) * tour_participants
+,SHARED3PAY_AM,((trips.trip_mode == 'SHARED3PAY') & is_am) * tour_participants
+,WALK_AM,((trips.trip_mode == 'WALK') & is_am) * tour_participants
+,BIKE_AM,((trips.trip_mode == 'BIKE') & is_am) * tour_participants
+,WALK_LOC_WALK_AM,((trips.trip_mode == 'WALK_LOC') & is_am) * tour_participants
+,WALK_LRF_WALK_AM,((trips.trip_mode == 'WALK_LRF') & is_am) * tour_participants
+,WALK_EXP_WALK_AM,((trips.trip_mode == 'WALK_EXP') & is_am) * tour_participants
+,WALK_HVY_WALK_AM,((trips.trip_mode == 'WALK_HVY') & is_am) * tour_participants
+,WALK_COM_WALK_AM,((trips.trip_mode == 'WALK_COM') & is_am) * tour_participants
+,DRIVE_LOC_WALK_AM,((trips.trip_mode == 'DRIVE_LOC') & is_am & trips.outbound) * tour_participants
+,DRIVE_LRF_WALK_AM,((trips.trip_mode == 'DRIVE_LRF') & is_am & trips.outbound) * tour_participants
+,DRIVE_EXP_WALK_AM,((trips.trip_mode == 'DRIVE_EXP') & is_am & trips.outbound) * tour_participants
+,DRIVE_HVY_WALK_AM,((trips.trip_mode == 'DRIVE_HVY') & is_am & trips.outbound) * tour_participants
+,DRIVE_COM_WALK_AM,((trips.trip_mode == 'DRIVE_COM') & is_am & trips.outbound) * tour_participants
+,WALK_LOC_DRIVE_AM,((trips.trip_mode == 'DRIVE_LOC') & is_am & ~trips.outbound) * tour_participants
+,WALK_LRF_DRIVE_AM,((trips.trip_mode == 'DRIVE_LRF') & is_am & ~trips.outbound) * tour_participants
+,WALK_EXP_DRIVE_AM,((trips.trip_mode == 'DRIVE_EXP') & is_am & ~trips.outbound) * tour_participants
+,WALK_DRIVE_HVY_AM,((trips.trip_mode == 'DRIVE_HVY') & is_am & ~trips.outbound) * tour_participants
+,WALK_COM_DRIVE_AM,((trips.trip_mode == 'DRIVE_COM') & is_am & ~trips.outbound) * tour_participants
+# md trips,,
+,DRIVEALONEFREE_MD,((trips.trip_mode == 'DRIVEALONEFREE') & is_md) * tour_participants
+,DRIVEALONEPAY_MD,((trips.trip_mode == 'DRIVEALONEPAY') & is_md) * tour_participants
+,SHARED2FREE_MD,((trips.trip_mode == 'SHARED2FREE') & is_md) * tour_participants
+,SHARED2PAY_MD,((trips.trip_mode == 'SHARED2PAY') & is_md) * tour_participants
+,SHARED3FREE_MD,((trips.trip_mode == 'SHARED3FREE') & is_md) * tour_participants
+,SHARED3PAY_MD,((trips.trip_mode == 'SHARED3PAY') & is_md) * tour_participants
+,WALK_MD,((trips.trip_mode == 'WALK') & is_md) * tour_participants
+,BIKE_MD,((trips.trip_mode == 'BIKE') & is_md) * tour_participants
+,WALK_LOC_WALK_MD,((trips.trip_mode == 'WALK_LOC') & is_md) * tour_participants
+,WALK_LRF_WALK_MD,((trips.trip_mode == 'WALK_LRF') & is_md) * tour_participants
+,WALK_EXP_WALK_MD,((trips.trip_mode == 'WALK_EXP') & is_md) * tour_participants
+,WALK_HVY_WALK_MD,((trips.trip_mode == 'WALK_HVY') & is_md) * tour_participants
+,WALK_COM_WALK_MD,((trips.trip_mode == 'WALK_COM') & is_md) * tour_participants
+,DRIVE_LOC_WALK_MD,((trips.trip_mode == 'DRIVE_LOC') & is_md & trips.outbound) * tour_participants
+,DRIVE_LRF_WALK_MD,((trips.trip_mode == 'DRIVE_LRF') & is_md & trips.outbound) * tour_participants
+,DRIVE_EXP_WALK_MD,((trips.trip_mode == 'DRIVE_EXP') & is_md & trips.outbound) * tour_participants
+,DRIVE_HVY_WALK_MD,((trips.trip_mode == 'DRIVE_HVY') & is_md & trips.outbound) * tour_participants
+,DRIVE_COM_WALK_MD,((trips.trip_mode == 'DRIVE_COM') & is_md & trips.outbound) * tour_participants
+,WALK_LOC_DRIVE_MD,((trips.trip_mode == 'DRIVE_LOC') & is_md & ~trips.outbound) * tour_participants
+,WALK_LRF_DRIVE_MD,((trips.trip_mode == 'DRIVE_LRF') & is_md & ~trips.outbound) * tour_participants
+,WALK_EXP_DRIVE_MD,((trips.trip_mode == 'DRIVE_EXP') & is_md & ~trips.outbound) * tour_participants
+,WALK_DRIVE_HVY_MD,((trips.trip_mode == 'DRIVE_HVY') & is_md & ~trips.outbound) * tour_participants
+,WALK_COM_DRIVE_MD,((trips.trip_mode == 'DRIVE_COM') & is_md & ~trips.outbound) * tour_participants
+# pm trips,,
+,DRIVEALONEFREE_PM,((trips.trip_mode == 'DRIVEALONEFREE') & is_pm) * tour_participants
+,DRIVEALONEPAY_PM,((trips.trip_mode == 'DRIVEALONEPAY') & is_pm) * tour_participants
+,SHARED2FREE_PM,((trips.trip_mode == 'SHARED2FREE') & is_pm) * tour_participants
+,SHARED2PAY_PM,((trips.trip_mode == 'SHARED2PAY') & is_pm) * tour_participants
+,SHARED3FREE_PM,((trips.trip_mode == 'SHARED3FREE') & is_pm) * tour_participants
+,SHARED3PAY_PM,((trips.trip_mode == 'SHARED3PAY') & is_pm) * tour_participants
+,WALK_PM,((trips.trip_mode == 'WALK') & is_pm) * tour_participants
+,BIKE_PM,((trips.trip_mode == 'BIKE') & is_pm) * tour_participants
+,WALK_LOC_WALK_PM,((trips.trip_mode == 'WALK_LOC') & is_pm) * tour_participants
+,WALK_LRF_WALK_PM,((trips.trip_mode == 'WALK_LRF') & is_pm) * tour_participants
+,WALK_EXP_WALK_PM,((trips.trip_mode == 'WALK_EXP') & is_pm) * tour_participants
+,WALK_HVY_WALK_PM,((trips.trip_mode == 'WALK_HVY') & is_pm) * tour_participants
+,WALK_COM_WALK_PM,((trips.trip_mode == 'WALK_COM') & is_pm) * tour_participants
+,DRIVE_LOC_WALK_PM,((trips.trip_mode == 'DRIVE_LOC') & is_pm & trips.outbound) * tour_participants
+,DRIVE_LRF_WALK_PM,((trips.trip_mode == 'DRIVE_LRF') & is_pm & trips.outbound) * tour_participants
+,DRIVE_EXP_WALK_PM,((trips.trip_mode == 'DRIVE_EXP') & is_pm & trips.outbound) * tour_participants
+,DRIVE_HVY_WALK_PM,((trips.trip_mode == 'DRIVE_HVY') & is_pm & trips.outbound) * tour_participants
+,DRIVE_COM_WALK_PM,((trips.trip_mode == 'DRIVE_COM') & is_pm & trips.outbound) * tour_participants
+,WALK_LOC_DRIVE_PM,((trips.trip_mode == 'DRIVE_LOC') & is_pm & ~trips.outbound) * tour_participants
+,WALK_LRF_DRIVE_PM,((trips.trip_mode == 'DRIVE_LRF') & is_pm & ~trips.outbound) * tour_participants
+,WALK_EXP_DRIVE_PM,((trips.trip_mode == 'DRIVE_EXP') & is_pm & ~trips.outbound) * tour_participants
+,WALK_DRIVE_HVY_PM,((trips.trip_mode == 'DRIVE_HVY') & is_pm & ~trips.outbound) * tour_participants
+,WALK_COM_DRIVE_PM,((trips.trip_mode == 'DRIVE_COM') & is_pm & ~trips.outbound) * tour_participants
+# ev trips,,
+,DRIVEALONEFREE_EV,((trips.trip_mode == 'DRIVEALONEFREE') & is_ev) * tour_participants
+,DRIVEALONEPAY_EV,((trips.trip_mode == 'DRIVEALONEPAY') & is_ev) * tour_participants
+,SHARED2FREE_EV,((trips.trip_mode == 'SHARED2FREE') & is_ev) * tour_participants
+,SHARED2PAY_EV,((trips.trip_mode == 'SHARED2PAY') & is_ev) * tour_participants
+,SHARED3FREE_EV,((trips.trip_mode == 'SHARED3FREE') & is_ev) * tour_participants
+,SHARED3PAY_EV,((trips.trip_mode == 'SHARED3PAY') & is_ev) * tour_participants
+,WALK_EV,((trips.trip_mode == 'WALK') & is_ev) * tour_participants
+,BIKE_EV,((trips.trip_mode == 'BIKE') & is_ev) * tour_participants
+,WALK_LOC_WALK_EV,((trips.trip_mode == 'WALK_LOC') & is_ev) * tour_participants
+,WALK_LRF_WALK_EV,((trips.trip_mode == 'WALK_LRF') & is_ev) * tour_participants
+,WALK_EXP_WALK_EV,((trips.trip_mode == 'WALK_EXP') & is_ev) * tour_participants
+,WALK_HVY_WALK_EV,((trips.trip_mode == 'WALK_HVY') & is_ev) * tour_participants
+,WALK_COM_WALK_EV,((trips.trip_mode == 'WALK_COM') & is_ev) * tour_participants
+,DRIVE_LOC_WALK_EV,((trips.trip_mode == 'DRIVE_LOC') & is_ev & trips.outbound) * tour_participants
+,DRIVE_LRF_WALK_EV,((trips.trip_mode == 'DRIVE_LRF') & is_ev & trips.outbound) * tour_participants
+,DRIVE_EXP_WALK_EV,((trips.trip_mode == 'DRIVE_EXP') & is_ev & trips.outbound) * tour_participants
+,DRIVE_HVY_WALK_EV,((trips.trip_mode == 'DRIVE_HVY') & is_ev & trips.outbound) * tour_participants
+,DRIVE_COM_WALK_EV,((trips.trip_mode == 'DRIVE_COM') & is_ev & trips.outbound) * tour_participants
+,WALK_LOC_DRIVE_EV,((trips.trip_mode == 'DRIVE_LOC') & is_ev & ~trips.outbound) * tour_participants
+,WALK_LRF_DRIVE_EV,((trips.trip_mode == 'DRIVE_LRF') & is_ev & ~trips.outbound) * tour_participants
+,WALK_EXP_DRIVE_EV,((trips.trip_mode == 'DRIVE_EXP') & is_ev & ~trips.outbound) * tour_participants
+,WALK_DRIVE_HVY_EV,((trips.trip_mode == 'DRIVE_HVY') & is_ev & ~trips.outbound) * tour_participants
+,WALK_COM_DRIVE_EV,((trips.trip_mode == 'DRIVE_COM') & is_ev & ~trips.outbound) * tour_participants
diff --git a/activitysim/examples/example_mtc/configs_mp/settings.yaml b/activitysim/examples/example_mtc/configs_mp/settings.yaml
index 6439f6924d..1f11116efa 100644
--- a/activitysim/examples/example_mtc/configs_mp/settings.yaml
+++ b/activitysim/examples/example_mtc/configs_mp/settings.yaml
@@ -87,6 +87,7 @@ models:
   - trip_mode_choice
   ### mp_summarize step
   - write_data_dictionary
+  - write_trip_matrices
   - write_tables
 
 multiprocess_steps:
diff --git a/activitysim/examples/example_mtc/output/.gitignore b/activitysim/examples/example_mtc/output/.gitignore
index b987779f45..bf5bf15e3e 100644
--- a/activitysim/examples/example_mtc/output/.gitignore
+++ b/activitysim/examples/example_mtc/output/.gitignore
@@ -4,3 +4,4 @@
 *.h5
 *.txt
 *.yaml
+*.omx
diff --git a/docs/abmexample.rst b/docs/abmexample.rst
index 8b11436171..cd7f84c97e 100644
--- a/docs/abmexample.rst
+++ b/docs/abmexample.rst
@@ -499,6 +499,9 @@ columns indicates the number of non-mandatory tours by purpose.  The current set
 +------------------------------------------------+--------------------------------------------------------------------+
 |  :ref:`trip_cbd_parking`                       |  **NOT YET IMPLEMENTED**                                           |
 +------------------------------------------------+--------------------------------------------------------------------+
+|  :ref:`write_trip_matrices`                    |  - write_trip_matrices.yaml                                        |
+|                                                |  - write_trip_matrices_annotate_trips_preprocessor.csv             |
++------------------------------------------------+--------------------------------------------------------------------+
 
 .. index:: chunk_size
 .. _chunk_size:
@@ -567,6 +570,7 @@ The ``models`` setting contains the specification of the data pipeline model ste
     - trip_mode_choice
     - write_data_dictionary
     - track_skim_usage
+    - write_trip_matrices
     - write_tables
 
 These model steps must be registered orca steps, as noted below.  If you provide a ``resume_after``
@@ -747,6 +751,10 @@ The example ``simulation.py`` run model script also writes the final tables to C
 the :func:`activitysim.core.pipeline.get_table` method via the ``write_tables`` step.
 This method returns a pandas DataFrame, which is then written to a CSV file by the ``write_tables`` step.
 
+The ``write_trip_matrices`` step processes the trips table to create open matrix (OMX) trip matrices for
+assignment.  The matrices are configured and coded according to the expressions in the model step
+trip annotation file.  See :ref:`write_trip_matrices` for more information.
+
 ActivitySim also writes log and trace files to the ``outputs`` folder.  The activitysim.log file,
 which is the overall log file is always produced.  If tracing is specified, then trace files are
 output as well.
diff --git a/docs/models.rst b/docs/models.rst
index b761b6972a..5e9e3377f5 100644
--- a/docs/models.rst
+++ b/docs/models.rst
@@ -789,6 +789,22 @@ XXXXX function.  This function is registered as an orca step in the example Pipe
 
 Core Table: ``trips`` | Result Field: ``XXXXX`` | Skims Keys: ``XXXXX``
 
+.. _write_trip_matrices:
+
+Write Trip Matrices
+-------------------
+
+Write open matrix (OMX) trip matrices for assignment.  Reads the trips table post preprocessor and run expressions 
+to code additional data fields, with one data fields for each matrix specified.  The matrices are scaled by a 
+household level expansion factor, which is the household sample rate by default, which is calculated when
+households are read in at the beginning of a model run.  The main interface to write trip
+matrices is the :py:func:`~activitysim.abm.models.trip_matrices.write_trip_matrices` function.  This function 
+is registered as an orca step in the example Pipeline.
+
+Core Table: ``trips`` | Result: ``omx trip matrices`` | Skims Keys: ``origin, destination``
+
+.. automodule:: activitysim.abm.models.trip_matrices
+   :members:
 
 .. _utility_steps:
 
diff --git a/scripts/simulation.py b/scripts/simulation.py
index 5871b99943..ddc592c244 100644
--- a/scripts/simulation.py
+++ b/scripts/simulation.py
@@ -29,6 +29,7 @@ def cleanup_output_files():
     tracing.delete_output_files('txt')
     tracing.delete_output_files('yaml')
     tracing.delete_output_files('prof')
+    tracing.delete_output_files('omx')
 
 
 def run(run_list, injectables=None):
diff --git a/setup.py b/setup.py
index f61ede7380..329a867f77 100644
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,7 @@
     install_requires=[
         'numpy >= 1.16.1',
         'openmatrix >= 0.3.4.1',
-        'pandas >= 0.24.1',
+        'pandas >= 1.0.1',
         'pyyaml >= 5.1',
         'tables >= 3.5.1',
         'toolz >= 0.8.1',