diff --git a/examples/quickstart-fr.py.py b/examples/quickstart-fr.py
similarity index 75%
rename from examples/quickstart-fr.py.py
rename to examples/quickstart-fr.py
index ebc32e82..d7deaa37 100644
--- a/examples/quickstart-fr.py.py
+++ b/examples/quickstart-fr.py
@@ -6,10 +6,8 @@
 dotenv.load_dotenv()
 
 mobility.set_params(
-    # package_data_folder_path=os.environ["MOBILITY_PACKAGE_DATA_FOLDER"],
-    # project_data_folder_path=os.environ["MOBILITY_PROJECT_DATA_FOLDER"]
-        package_data_folder_path="D:/mobility-data",
-        project_data_folder_path="D:/test-09",
+    package_data_folder_path=os.environ["MOBILITY_PACKAGE_DATA_FOLDER"],
+    project_data_folder_path=os.environ["MOBILITY_PROJECT_DATA_FOLDER"]
 )
 
 # Using Foix (a small town) and a limited radius for quick results
@@ -21,10 +19,10 @@
 # Creating a synthetic population of 1000 for the area
 pop = mobility.Population(transport_zones, sample_size = 1000)
 
-# Simulating the trips for this population for three modes : car, walk and bicyle, and only home and work motives (OtherMotive is mandatory)
+# Simulating the trips for this population for three modes : car, walk, bicyle and public transport, and only home and work motives (OtherMotive is mandatory)
 pop_trips = mobility.PopulationTrips(
     pop,
-    [mobility.CarMode(transport_zones), mobility.WalkMode(transport_zones), mobility.BicycleMode(transport_zones)],
+    [mobility.CarMode(transport_zones), mobility.WalkMode(transport_zones), mobility.BicycleMode(transport_zones), mobility.PublicTransportMode(transport_zones)],
     [mobility.HomeMotive(), mobility.WorkMotive(), mobility.OtherMotive(population=pop)],
     [emp]
     )
diff --git a/mobility/transport_modes/modal_transfer.py b/mobility/transport_modes/modal_transfer.py
index 9568a95b..84889664 100644
--- a/mobility/transport_modes/modal_transfer.py
+++ b/mobility/transport_modes/modal_transfer.py
@@ -11,20 +11,24 @@ class IntermodalTransfer():
     Dataclass for intermodal transfer parameters.
     
     Args:
-        max_travel_time: maximum travel time to consider when estima
+        max_travel_time: maximum travel time to consider between those two modes
+        average_speed: average speed during the transfer (default is 4.0 km/h, considering walking)
+        transfer_time: to document
+        shortcuts_transfer_time: to document
+        shortcuts_locations: to document
     """
     
     # Max travel time from or to the connection nodes, estimated from the crow
     # fly distance around connection nodes and an average speed
-    max_travel_time: float # hours
-    average_speed: float # km/h
+    max_travel_time: float = 20.0 / 60.0 # hours
+    average_speed: float = 4.0 # km/h
     
     # Average transfer time between the two connected modes
-    transfer_time: float # minutes
+    transfer_time: float = 1.0 # minutes
     
     # Optional shortcuts to make some connections faster than average
     shortcuts_transfer_time: float = None # minutes
     shortcuts_locations: List[Coordinates] = None
     
     
-    
\ No newline at end of file
+    
diff --git a/mobility/transport_modes/public_transport/public_transport_mode.py b/mobility/transport_modes/public_transport/public_transport_mode.py
index 2837f046..7c9de85a 100644
--- a/mobility/transport_modes/public_transport/public_transport_mode.py
+++ b/mobility/transport_modes/public_transport/public_transport_mode.py
@@ -4,6 +4,7 @@
 
 from mobility.transport_zones import TransportZones
 from mobility.transport_modes.transport_mode import TransportMode
+from mobility.transport_modes.walk import WalkMode
 from mobility.transport_modes.public_transport.public_transport_routing_parameters import PublicTransportRoutingParameters
 from mobility.transport_modes.public_transport.public_transport_travel_costs import PublicTransportTravelCosts
 from mobility.transport_modes.public_transport.public_transport_generalized_cost import PublicTransportGeneralizedCost
@@ -32,8 +33,8 @@ def __init__(
         transport_zones: TransportZones,
         first_leg_mode: TransportMode = None,
         last_leg_mode: TransportMode = None,
-        first_intermodal_transfer: IntermodalTransfer = None,
-        last_intermodal_transfer: IntermodalTransfer = None,
+        first_intermodal_transfer: IntermodalTransfer =  IntermodalTransfer(),
+        last_intermodal_transfer: IntermodalTransfer =  IntermodalTransfer(),
         routing_parameters: PublicTransportRoutingParameters = PublicTransportRoutingParameters(),
         generalized_cost_parameters: GeneralizedCostParameters = None,
         survey_ids: List[str] = [
@@ -43,6 +44,11 @@ def __init__(
         ],
         ghg_intensity: float = 0.05
     ):
+
+        if first_leg_mode is None:
+            first_leg_mode = WalkMode(transport_zones)
+        if last_leg_mode is None:
+            last_leg_mode = WalkMode(transport_zones)
         
         travel_costs = PublicTransportTravelCosts(
             transport_zones,
@@ -94,4 +100,4 @@ def __init__(
     def audit_gtfs(self):
         logging.info("Auditing GTFS for this mode")
         travel_costs = self.travel_costs.audit_gtfs()
-        return travel_costs
\ No newline at end of file
+        return travel_costs
diff --git a/tests/back/integration/test_008_population_trips_can_be_computed.py b/tests/back/integration/test_008_population_trips_can_be_computed.py
index 7e59c5dd..84e6bbd9 100644
--- a/tests/back/integration/test_008_population_trips_can_be_computed.py
+++ b/tests/back/integration/test_008_population_trips_can_be_computed.py
@@ -141,7 +141,7 @@ def test_008_population_trips_can_be_computed(test_data, safe_json):
 
     pop_trips = PopulationTrips(
         population=pop,
-        modes=[mobility.CarMode(transport_zones)],
+        modes=[mobility.CarMode(transport_zones), mobility.WalkMode(transport_zones), mobility.BicycleMode(transport_zones), mobility.PublicTransportMode(transport_zones)],
         motives=[
             HomeMotive(),
             WorkMotive(),