diff --git a/include/boost/iostreams/detail/adapter/concept_adapter.hpp b/include/boost/iostreams/detail/adapter/concept_adapter.hpp
index bd2c1d5..766e258 100755
--- a/include/boost/iostreams/detail/adapter/concept_adapter.hpp
+++ b/include/boost/iostreams/detail/adapter/concept_adapter.hpp
@@ -14,7 +14,6 @@
 #include <boost/iostreams/categories.hpp>
 #include <boost/iostreams/detail/dispatch.hpp>
 #include <boost/iostreams/detail/error.hpp>
-#include <boost/iostreams/detail/ios_traits.hpp>
 #include <boost/iostreams/device/null.hpp>
 #include <boost/iostreams/traits.hpp>
 #include <boost/iostreams/is_device.hpp>
diff --git a/include/boost/iostreams/detail/enable_if_stream.hpp b/include/boost/iostreams/detail/enable_if_stream.hpp
index 81299ba..62e2cc6 100755
--- a/include/boost/iostreams/detail/enable_if_stream.hpp
+++ b/include/boost/iostreams/detail/enable_if_stream.hpp
@@ -11,9 +11,9 @@
 # pragma once
 #endif              
 
-#include <boost/config.hpp>                         // BOOST_NO_SFINAE 
+#include <boost/config.hpp>             // BOOST_NO_SFINAE 
 #include <boost/utility/enable_if.hpp>                  
-#include <boost/iostreams/detail/ios_traits.hpp>    // is_std_io.
+#include <boost/iostreams/traits.hpp>   // is_std_io.
 
 #ifndef BOOST_NO_SFINAE
 # define BOOST_IOSTREAMS_ENABLE_IF_STREAM(T) \
diff --git a/include/boost/iostreams/detail/param_type.hpp b/include/boost/iostreams/detail/param_type.hpp
index 1e3c4d1..b04a99c 100755
--- a/include/boost/iostreams/detail/param_type.hpp
+++ b/include/boost/iostreams/detail/param_type.hpp
@@ -11,7 +11,7 @@
 # pragma once
 #endif              
 
-#include <boost/iostreams/detail/ios_traits.hpp>
+#include <boost/iostreams/traits.hpp>
 #include <boost/mpl/if.hpp>
 
 namespace boost { namespace iostreams { namespace detail {
diff --git a/include/boost/iostreams/detail/resolve.hpp b/include/boost/iostreams/detail/resolve.hpp
index 6038abb..929bf9b 100755
--- a/include/boost/iostreams/detail/resolve.hpp
+++ b/include/boost/iostreams/detail/resolve.hpp
@@ -20,7 +20,6 @@
 #include <boost/iostreams/detail/adapter/range_adapter.hpp>
 #include <boost/iostreams/detail/config/overload_resolution.hpp>
 #include <boost/iostreams/detail/enable_if_stream.hpp>
-#include <boost/iostreams/detail/ios_traits.hpp>  // is_std_io.  
 #include <boost/iostreams/detail/is_dereferenceable.hpp>
 #include <boost/iostreams/detail/is_iterator_range.hpp>
 #include <boost/iostreams/detail/select.hpp>
diff --git a/include/boost/iostreams/detail/wrap_unwrap.hpp b/include/boost/iostreams/detail/wrap_unwrap.hpp
index cd1590c..8ec477c 100755
--- a/include/boost/iostreams/detail/wrap_unwrap.hpp
+++ b/include/boost/iostreams/detail/wrap_unwrap.hpp
@@ -13,7 +13,7 @@
 
 #include <boost/config.hpp>                             // SFINAE.
 #include <boost/iostreams/detail/enable_if_stream.hpp>
-#include <boost/iostreams/detail/ios_traits.hpp>        // is_std_io.
+#include <boost/iostreams/traits.hpp>                   // is_std_io.
 #include <boost/mpl/bool.hpp>
 #include <boost/mpl/identity.hpp>
 #include <boost/mpl/eval_if.hpp>
diff --git a/include/boost/iostreams/device/array.hpp b/include/boost/iostreams/device/array.hpp
index 7b9f362..5f6cd23 100755
--- a/include/boost/iostreams/device/array.hpp
+++ b/include/boost/iostreams/device/array.hpp
@@ -16,7 +16,6 @@
 #include <cstddef>                  // std::size_t.
 #include <utility>                  // pair.
 #include <boost/iostreams/categories.hpp>
-#include <boost/iostreams/detail/ios_traits.hpp>
 #include <boost/preprocessor/cat.hpp>
 #include <boost/static_assert.hpp>
 #include <boost/type_traits/is_convertible.hpp>
@@ -94,7 +93,7 @@ BOOST_IOSTREAMS_ARRAY(array, seekable)
 #undef BOOST_IOSTREAMS_ARRAY
 
 
-//------------------Implementation of array_adapter------------------------------//
+//------------------Implementation of array_adapter---------------------------//
 
 namespace detail {
 
diff --git a/include/boost/iostreams/operations.hpp b/include/boost/iostreams/operations.hpp
index da7cd61..346cc21 100755
--- a/include/boost/iostreams/operations.hpp
+++ b/include/boost/iostreams/operations.hpp
@@ -15,7 +15,6 @@
 #include <boost/config.hpp>  // NO_STD_LOCALE, DEDUCED_TYPENAME, MSVC.
 #include <boost/detail/workaround.hpp>
 #include <boost/iostreams/detail/dispatch.hpp>
-#include <boost/iostreams/detail/ios_traits.hpp>
 #include <boost/iostreams/detail/wrap_unwrap.hpp>
 #include <boost/iostreams/traits.hpp>
 #include <boost/mpl/bool.hpp>
diff --git a/include/boost/iostreams/traits.hpp b/include/boost/iostreams/traits.hpp
index 923e257..f6d3960 100755
--- a/include/boost/iostreams/traits.hpp
+++ b/include/boost/iostreams/traits.hpp
@@ -18,25 +18,41 @@
 # pragma once
 #endif              
 
-#include <iosfwd>                           // streamsize.
-#include <string>                           // char_traits. 
-#include <boost/config.hpp>                 // partial spec, deduced typename.
+#include <iosfwd>            // stream types, char_traits.
+#include <boost/config.hpp>  // partial spec, deduced typename.
 #include <boost/iostreams/categories.hpp>
-#include <boost/iostreams/detail/select.hpp>        
-#include <boost/iostreams/detail/ios_traits.hpp>     
-#include <boost/iostreams/detail/is_iterator_range.hpp>        
+#include <boost/iostreams/detail/bool_trait_def.hpp> 
+#include <boost/iostreams/detail/is_iterator_range.hpp>    
+#include <boost/iostreams/detail/select.hpp>            
 #include <boost/iostreams/detail/wrap_unwrap.hpp> 
 #include <boost/mpl/eval_if.hpp>
 #include <boost/mpl/identity.hpp>      
 #include <boost/mpl/int.hpp>  
+#include <boost/mpl/or.hpp>                         
 #include <boost/range/iterator_range.hpp>
 #include <boost/range/value_type.hpp>
 #include <boost/type_traits/is_convertible.hpp>     
 #define BOOST_SELECT_BY_SIZE_MAX_CASE 9     
-#include <boost/iostreams/detail/select_by_size.hpp>                     
+#include <boost/iostreams/detail/select_by_size.hpp>    
+
+//------------------Definitions of predicates for stream types----------------//
+
+BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_istream, std::basic_istream, 2)
+BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_ostream, std::basic_ostream, 2)
+BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_iostream, std::basic_iostream, 2)
+BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_streambuf, std::basic_streambuf, 2)
+BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_stringstream, std::basic_stringstream, 3)
+BOOST_IOSTREAMS_BOOL_TRAIT_DEF(is_stringbuf, std::basic_stringbuf, 3)
 
 namespace boost { namespace iostreams {          
 
+//------------------Definitions of is_std_io----------------------------------//
+
+template<typename T>
+struct is_std_io
+    : mpl::or_< is_istream<T>, is_ostream<T>, is_streambuf<T> >
+    { };
+
 //------------------Definitions of io_char------------------------------------//
 
 namespace detail {