diff --git a/esrally/mechanic/team.py b/esrally/mechanic/team.py
index f0f2b5d23..e12af2400 100644
--- a/esrally/mechanic/team.py
+++ b/esrally/mechanic/team.py
@@ -19,8 +19,8 @@
 import logging
 import os
 from enum import Enum
-from typing import Any, Collection, Mapping, Union
 from types import ModuleType
+from typing import Any, Collection, Mapping, Union
 
 import tabulate
 
@@ -49,7 +49,7 @@ def list_cars(cfg: types.Config):
     console.println(tabulate.tabulate([[c.name, c.type, c.description] for c in cars], headers=["Name", "Type", "Description"]))
 
 
-def load_car(repo: str, name: Collection[str], car_params: Mapping=None) -> "Car":
+def load_car(repo: str, name: Collection[str], car_params: Mapping = None) -> "Car":
     class Component:
         def __init__(self, root_path, entry_point):
             self.root_path = root_path
@@ -240,7 +240,7 @@ class Car:
     def __init__(
         self,
         names: Collection[str],
-        root_path: Union[str, Collection[str]],
+        root_path: Union[None, str, Collection[str]],
         config_paths: Collection[str],
         variables: Mapping[str, Any] = None,
     ):
@@ -259,7 +259,9 @@ def __init__(
         else:
             self.names = names
 
-        if isinstance(root_path, str):
+        if root_path is None:
+            self.root_path = []
+        elif isinstance(root_path, str):
             self.root_path = [root_path]
         else:
             self.root_path = root_path
diff --git a/esrally/utils/modules.py b/esrally/utils/modules.py
index 555663954..b0396becb 100644
--- a/esrally/utils/modules.py
+++ b/esrally/utils/modules.py
@@ -19,8 +19,8 @@
 import logging
 import os
 import sys
-from typing import Collection, Union
 from types import ModuleType
+from typing import Collection, Union
 
 from esrally import exceptions
 from esrally.utils import io
@@ -65,7 +65,7 @@ def _load_component(self, component_name: str, module_dirs: Collection[str], roo
         # precondition: A module with this name has to exist provided that the caller has called #can_load() before.
         root_module_name = "%s.%s" % (component_name, self.component_entry_point)
         for name, p in self._modules(module_dirs, component_name, root_path):
-            self.logger.debug(f"Loading module [{name}]: {p}")
+            self.logger.debug("Loading module [%s]: %s", name, p)
             spec = importlib.util.spec_from_file_location(name, p)
             m = importlib.util.module_from_spec(spec)
             spec.loader.exec_module(m)
@@ -118,6 +118,5 @@ def load(self) -> Collection[ModuleType]:
             except BaseException:
                 msg = f"Could not load component [{component_name}]"
                 self.logger.exception(msg)
-                raise
-                # raise exceptions.SystemSetupError(msg)
+                raise exceptions.SystemSetupError(msg)
         return root_modules
diff --git a/esrally/utils/process.py b/esrally/utils/process.py
index 597a31a51..ab28ec63e 100644
--- a/esrally/utils/process.py
+++ b/esrally/utils/process.py
@@ -142,7 +142,6 @@ def run_subprocess_with_logging_and_output(
     if header is not None:
         logger.info(header)
 
-    # pylint: disable=subprocess-popen-preexec-fn
     completed = subprocess.run(
         command_line_args,
         stdout=subprocess.PIPE,
diff --git a/tests/mechanic/provisioner_test.py b/tests/mechanic/provisioner_test.py
index d4a8ac982..fe6aeae4b 100644
--- a/tests/mechanic/provisioner_test.py
+++ b/tests/mechanic/provisioner_test.py
@@ -42,7 +42,7 @@ def null_apply_config(source_root_path, target_root_path, config_vars):
         installer = provisioner.ElasticsearchInstaller(
             car=team.Car(
                 names="unit-test-car",
-                root_path=None,  # type: ignore
+                root_path=None,
                 config_paths=[HOME_DIR + "/.rally/benchmarks/teams/default/my-car"],
                 variables={
                     "heap": "4g",