diff --git a/etc/neutron.conf b/etc/neutron.conf
index 2dd42c48c8..e3b6fac01a 100644
--- a/etc/neutron.conf
+++ b/etc/neutron.conf
@@ -288,7 +288,7 @@ notification_driver = neutron.openstack.common.notifier.rpc_notifier
 # quota_security_group_rule = 100
 
 # default driver to use for quota checks
-# quota_driver = neutron.quota.ConfDriver
+# quota_driver = neutron.db.quota_db.DbQuotaDriver
 
 [agent]
 # Use "sudo neutron-rootwrap /etc/neutron/rootwrap.conf" to use the real
diff --git a/neutron/quota.py b/neutron/quota.py
index 02a7cebd61..908b256f2c 100644
--- a/neutron/quota.py
+++ b/neutron/quota.py
@@ -47,7 +47,7 @@ quota_opts = [
                help=_('Number of ports allowed per tenant, minus for '
                       'unlimited')),
     cfg.StrOpt('quota_driver',
-               default='neutron.quota.ConfDriver',
+               default='neutron.db.quota_db.DbQuotaDriver',
                help=_('Default driver to use for quota checks')),
 ]
 # Register the configuration options
@@ -209,14 +209,18 @@ class QuotaEngine(object):
     def __init__(self, quota_driver_class=None):
         """Initialize a Quota object."""
 
-        if not quota_driver_class:
-            quota_driver_class = cfg.CONF.QUOTAS.quota_driver
-
-        if isinstance(quota_driver_class, basestring):
-            quota_driver_class = importutils.import_object(quota_driver_class)
-
         self._resources = {}
-        self._driver = quota_driver_class
+        self._driver = None
+        self._driver_class = quota_driver_class
+
+    def get_driver(self):
+        if self._driver is None:
+            _driver_class = (self._driver_class or
+                             cfg.CONF.QUOTAS.quota_driver)
+            if isinstance(_driver_class, basestring):
+                _driver_class = importutils.import_object(_driver_class)
+            self._driver = _driver_class
+        return self._driver
 
     def __contains__(self, resource):
         return resource in self._resources
@@ -281,8 +285,8 @@ class QuotaEngine(object):
         :param context: The request context, for access checks.
         """
 
-        return self._driver.limit_check(context, tenant_id,
-                                        self._resources, values)
+        return self.get_driver().limit_check(context, tenant_id,
+                                             self._resources, values)
 
     @property
     def resources(self):
diff --git a/neutron/tests/unit/nicira/test_networkgw.py b/neutron/tests/unit/nicira/test_networkgw.py
index ab19a6c3ce..5a4259e5eb 100644
--- a/neutron/tests/unit/nicira/test_networkgw.py
+++ b/neutron/tests/unit/nicira/test_networkgw.py
@@ -32,6 +32,7 @@ from neutron.db import db_base_plugin_v2
 from neutron import manager
 from neutron.plugins.nicira.dbexts import nicira_networkgw_db
 from neutron.plugins.nicira.extensions import nvp_networkgw as networkgw
+from neutron import quota
 from neutron.tests import base
 from neutron.tests.unit import test_api_v2
 from neutron.tests.unit import test_db_plugin
@@ -93,6 +94,10 @@ class NetworkGatewayExtensionTestCase(base.BaseTestCase):
         self.ext_mdw = test_extensions.setup_extensions_middleware(ext_mgr)
         self.api = webtest.TestApp(self.ext_mdw)
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
     def test_network_gateway_create(self):
         nw_gw_id = _uuid()
         data = {self._resource: {'name': 'nw-gw',
diff --git a/neutron/tests/unit/services/vpn/test_vpnaas_extension.py b/neutron/tests/unit/services/vpn/test_vpnaas_extension.py
index d1f8954534..b3acadf575 100644
--- a/neutron/tests/unit/services/vpn/test_vpnaas_extension.py
+++ b/neutron/tests/unit/services/vpn/test_vpnaas_extension.py
@@ -31,6 +31,7 @@ from neutron.extensions import vpnaas
 from neutron import manager
 from neutron.openstack.common import uuidutils
 from neutron.plugins.common import constants
+from neutron import quota
 from neutron.tests.unit import test_api_v2
 from neutron.tests.unit import test_extensions
 from neutron.tests.unit import testlib_api
@@ -88,6 +89,10 @@ class VpnaasExtensionTestCase(testlib_api.WebTestCase):
         self.api = webtest.TestApp(self.ext_mdw)
         super(VpnaasExtensionTestCase, self).setUp()
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
     def tearDown(self):
         self._plugin_patcher.stop()
         self.api = None
diff --git a/neutron/tests/unit/test_api_v2.py b/neutron/tests/unit/test_api_v2.py
index 3268bbac18..61e3eb371a 100644
--- a/neutron/tests/unit/test_api_v2.py
+++ b/neutron/tests/unit/test_api_v2.py
@@ -36,6 +36,7 @@ from neutron.manager import NeutronManager
 from neutron.openstack.common.notifier import api as notifer_api
 from neutron.openstack.common import policy as common_policy
 from neutron.openstack.common import uuidutils
+from neutron import quota
 from neutron.tests import base
 from neutron.tests.unit import testlib_api
 
@@ -118,6 +119,10 @@ class APIv2TestBase(base.BaseTestCase):
         api = router.APIRouter()
         self.api = webtest.TestApp(api)
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
 
 class _ArgMatcher(object):
     """An adapter to assist mock assertions, used to custom compare."""
@@ -1377,6 +1382,10 @@ class ExtensionTestCase(base.BaseTestCase):
         api = router.APIRouter()
         self.api = webtest.TestApp(api)
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
     def tearDown(self):
         super(ExtensionTestCase, self).tearDown()
         self._plugin_patcher.stop()
diff --git a/neutron/tests/unit/test_extension_extended_attribute.py b/neutron/tests/unit/test_extension_extended_attribute.py
index 92a0c3cecd..6cc32f0a96 100644
--- a/neutron/tests/unit/test_extension_extended_attribute.py
+++ b/neutron/tests/unit/test_extension_extended_attribute.py
@@ -29,6 +29,7 @@ from neutron.common import config
 from neutron import manager
 from neutron.plugins.common import constants
 from neutron.plugins.openvswitch import ovs_neutron_plugin
+from neutron import quota
 from neutron.tests import base
 from neutron.tests.unit.extensions import extendedattribute as extattr
 from neutron.tests.unit import test_api_v2
@@ -108,6 +109,10 @@ class ExtensionExtendedAttributeTestCase(base.BaseTestCase):
         self.addCleanup(cfg.CONF.reset)
         self.addCleanup(self.restore_attribute_map)
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
     def restore_attribute_map(self):
         # Restore the original RESOURCE_ATTRIBUTE_MAP
         attributes.RESOURCE_ATTRIBUTE_MAP = self.saved_attr_map
diff --git a/neutron/tests/unit/test_extension_pnet.py b/neutron/tests/unit/test_extension_pnet.py
index 41080052ed..f69d6b14b1 100644
--- a/neutron/tests/unit/test_extension_pnet.py
+++ b/neutron/tests/unit/test_extension_pnet.py
@@ -30,6 +30,7 @@ from neutron import context
 from neutron.extensions import providernet as pnet
 from neutron.manager import NeutronManager
 from neutron.openstack.common import uuidutils
+from neutron import quota
 from neutron.tests.unit import test_api_v2
 from neutron.tests.unit import test_extensions
 from neutron.tests.unit import testlib_api
@@ -87,6 +88,10 @@ class ProvidernetExtensionTestCase(testlib_api.WebTestCase):
         self.addCleanup(self._restore_attribute_map)
         self.api = webtest.TestApp(router.APIRouter())
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
     def _restore_attribute_map(self):
         # Restore the global RESOURCE_ATTRIBUTE_MAP
         attributes.RESOURCE_ATTRIBUTE_MAP = self.saved_attr_map
diff --git a/neutron/tests/unit/test_l3_plugin.py b/neutron/tests/unit/test_l3_plugin.py
index 0c7aef7002..4f75b576cf 100644
--- a/neutron/tests/unit/test_l3_plugin.py
+++ b/neutron/tests/unit/test_l3_plugin.py
@@ -46,6 +46,7 @@ from neutron.openstack.common.notifier import api as notifier_api
 from neutron.openstack.common.notifier import test_notifier
 from neutron.openstack.common import uuidutils
 from neutron.plugins.common import constants as service_constants
+from neutron import quota
 from neutron.tests.unit import test_api_v2
 from neutron.tests.unit import test_db_plugin
 from neutron.tests.unit import test_extensions
@@ -114,6 +115,10 @@ class L3NatExtensionTestCase(testlib_api.WebTestCase):
         self.ext_mdw = test_extensions.setup_extensions_middleware(ext_mgr)
         self.api = webtest.TestApp(self.ext_mdw)
 
+        quota.QUOTAS._driver = None
+        cfg.CONF.set_override('quota_driver', 'neutron.quota.ConfDriver',
+                              group='QUOTAS')
+
     def tearDown(self):
         self._plugin_patcher.stop()
         self.api = None
diff --git a/neutron/tests/unit/test_quota_ext.py b/neutron/tests/unit/test_quota_ext.py
index 9e462edff1..3f572adf6d 100644
--- a/neutron/tests/unit/test_quota_ext.py
+++ b/neutron/tests/unit/test_quota_ext.py
@@ -327,6 +327,13 @@ class QuotaExtensionDbTestCaseXML(QuotaExtensionDbTestCase):
 class QuotaExtensionCfgTestCase(QuotaExtensionTestCase):
     fmt = 'json'
 
+    def setUp(self):
+        cfg.CONF.set_override(
+            'quota_driver',
+            'neutron.quota.ConfDriver',
+            group='QUOTAS')
+        super(QuotaExtensionCfgTestCase, self).setUp()
+
     def test_quotas_default_values(self):
         tenant_id = 'tenant_id1'
         env = {'neutron.context': context.Context('', tenant_id)}