diff -u b/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
--- b/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -3166,7 +3166,7 @@
     $loader->registerNamespaces(array(
       'Drupal\Core' => DRUPAL_ROOT . '/core/lib',
       'Drupal\Component' => DRUPAL_ROOT . '/core/lib',
-      'Drupal\Drivers' => DRUPAL_ROOT . '/drivers/lib',
+      'Drupal\Driver' => DRUPAL_ROOT . '/drivers/lib',
     ));
 
     // Register namespaces and PEAR-like prefixes for vendor libraries managed
diff -u b/core/includes/install.inc b/core/includes/install.inc
--- b/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -134,9 +134,11 @@
   // contains a database.inc file. That allows us to drop in additional drivers
   // without modifying the installer.
   require_once DRUPAL_ROOT . '/core/includes/database.inc';
-  $files = file_scan_directory(DRUPAL_ROOT . '/core/lib/Drupal/Core/Database/Driver', '/^[a-z]*$/i', array('recurse' => FALSE));
-  if (is_dir(DRUPAL_ROOT . '/drivers/lib/Drupal/Drivers/Database')) {
-    $files += file_scan_directory(DRUPAL_ROOT . '/drivers/lib/Drupal/Drivers/Database/', '/^[a-z_]+$/i', array('recurse' => FALSE));
+  // Allow any valid PHP identifier.
+  $mask = '/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$/';
+  $files = file_scan_directory(DRUPAL_ROOT . '/core/lib/Drupal/Core/Database/Driver', $mask, array('recurse' => FALSE));
+  if (is_dir(DRUPAL_ROOT . '/drivers/lib/Drupal/Driver/Database')) {
+    $files += file_scan_directory(DRUPAL_ROOT . '/drivers/lib/Drupal/Driver/Database/', $mask, array('recurse' => FALSE));
   }
   foreach ($files as $file) {
     if (file_exists($file->uri . '/Install/Tasks.php')) {
@@ -961,7 +963,7 @@
     return new $task_class();
   }
   else {
-    $task_class = "Drupal\\Drivers\\Database\\{$driver}\\Install\\Tasks";
+    $task_class = "Drupal\\Driver\\Database\\{$driver}\\Install\\Tasks";
     return new $task_class();
   }
 }
diff -u b/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
--- b/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -624,6 +624,7 @@
         $driver_class  = $this->connectionOptions['namespace'] . '\\' . $class;
       }
       else {
+        // Fallback for Drupal 7 settings.php.
         $driver_class = "Drupal\\Core\\Database\\Driver\\{$driver}\\{$class}";
       }
       $this->driverClasses[$class] = class_exists($driver_class) ? $driver_class : $class;
diff -u b/core/lib/Drupal/Core/Database/Database.php b/core/lib/Drupal/Core/Database/Database.php
--- b/core/lib/Drupal/Core/Database/Database.php
+++ b/core/lib/Drupal/Core/Database/Database.php
@@ -378,6 +378,7 @@
       $driver_class = self::$databaseInfo[$key][$target]['namespace'] . '\\Connection';
     }
     else {
+      // Fallback for Drupal 7 settings.php.
       $driver_class = "Drupal\\Core\\Database\\Driver\\{$driver}\\Connection";
     }
     $new_connection = new $driver_class(self::$databaseInfo[$key][$target]);