diff --git a/actionpack/lib/action_dispatch/journey/router/utils.rb b/actionpack/lib/action_dispatch/journey/router/utils.rb
index 80011597aa..810f86db2f 100644
--- a/actionpack/lib/action_dispatch/journey/router/utils.rb
+++ b/actionpack/lib/action_dispatch/journey/router/utils.rb
@@ -36,7 +36,7 @@ module ActionDispatch
           UNSAFE_FRAGMENT = Regexp.new("[^#{safe_fragment}]", false).freeze
         end
 
-        Parser = URI.const_defined?(:Parser) ? URI::Parser.new : URI
+        Parser = URI::Parser.new
 
         def self.escape_path(path)
           Parser.escape(path.to_s, UriEscape::UNSAFE_SEGMENT)