diff --git a/README.md b/README.md
index 6b7c0bb9..65240c62 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,7 @@
 
 ```cpp
 #include <units/physical/si/velocity.h>
+#include <units/physical/us/velocity.h>
 #include <units/format.h>
 #include <iostream>
 
@@ -23,7 +24,7 @@ int main()
 {
   using namespace si::literals;
   Velocity auto v1 = avg_speed(220km, 2h);
-  Velocity auto v2 = avg_speed(si::length<si::mile>(140), si::time<si::hour>(2));
+  Velocity auto v2 = avg_speed(si::length<us::mile>(140), si::time<si::hour>(2));
   Velocity auto v3 = quantity_cast<si::metre_per_second>(v2);
   Velocity auto v4 = quantity_cast<int>(v3);
 
@@ -152,6 +153,7 @@ fashion:
 int main()
 {
   using namespace si::literals;
+  using namespace us::literals;
   Velocity auto v1 = avg_speed(220km, 2h);
   Velocity auto v2 = avg_speed(140mi, 2h);
 
diff --git a/doc/DESIGN.md b/doc/DESIGN.md
index 2d543005..9dd42c69 100644
--- a/doc/DESIGN.md
+++ b/doc/DESIGN.md
@@ -150,8 +150,6 @@ struct kilo : units::prefix<kilo, prefix, "k", ratio<1'000>> {};
 struct metre : named_unit<metre, "m", prefix> {};
 struct centimetre : prefixed_unit<centimetre, centi, metre> {};
 struct kilometre : prefixed_unit<kilometre, kilo, metre> {};
-struct yard : named_scaled_unit<yard, "yd", no_prefix, ratio<9'144, 10'000>, metre> {};
-struct mile : named_scaled_unit<mile, "mi", no_prefix, ratio<1'760>, yard> {};
 
 // time
 struct second : named_unit<second, "s", prefix> {};
@@ -160,7 +158,17 @@ struct hour : named_scaled_unit<hour, "h", no_prefix, ratio<3600>, second> {};
 // velocity
 struct metre_per_second : unit<metre_per_second> {};
 struct kilometre_per_hour : deduced_unit<kilometre_per_hour, dim_velocity, kilometre, hour> {};
-struct mile_per_hour : deduced_unit<mile_per_hour, dim_velocity, mile, hour> {};
+
+}
+
+namespace units::us {
+
+// length
+struct yard : named_scaled_unit<yard, "yd", no_prefix, ratio<9'144, 10'000>, si::metre> {};
+struct mile : named_scaled_unit<mile, "mi", no_prefix, ratio<1'760>, yard> {};
+
+// velocity
+struct mile_per_hour : deduced_unit<mile_per_hour, si::dim_velocity, mile, si::hour> {};
 
 }
 ```
diff --git a/example/avg_velocity.cpp b/example/avg_velocity.cpp
index 49d65993..5c1bfae5 100644
--- a/example/avg_velocity.cpp
+++ b/example/avg_velocity.cpp
@@ -20,8 +20,9 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include <units/physical/si/velocity.h>
 #include <units/physical/cgs/velocity.h>
+#include <units/physical/si/velocity.h>
+#include <units/physical/us/velocity.h>
 #include <iostream>
 
 namespace {
@@ -96,7 +97,7 @@ void example()
 
   // Customary Units (int)
   {
-    using namespace units::si::literals;
+    using namespace units::us::literals;
     constexpr Length AUTO distance = 140mi;        // constructed from a UDL
     constexpr si::time<si::hour, int> duration(2); // constructed from a value
 
@@ -112,7 +113,7 @@ void example()
 
   // Customary Units (double)
   {
-    using namespace units::si::literals;
+    using namespace units::us::literals;
     constexpr Length AUTO distance = 140.mi;  // constructed from a UDL
     constexpr si::time<si::hour> duration(2); // constructed from a value
 
diff --git a/example/hello_units.cpp b/example/hello_units.cpp
index 2a933e59..3ca1dde8 100644
--- a/example/hello_units.cpp
+++ b/example/hello_units.cpp
@@ -21,6 +21,7 @@
 // SOFTWARE.
 
 #include <units/physical/si/velocity.h>
+#include <units/physical/us/velocity.h>
 #include <units/format.h>
 #include <iostream>
 
@@ -35,7 +36,7 @@ int main()
 {
   using namespace si::literals;
   Velocity AUTO v1 = avg_speed(220km, 2h);
-  Velocity AUTO v2 = avg_speed(si::length<si::mile>(140), si::time<si::hour>(2));
+  Velocity AUTO v2 = avg_speed(si::length<us::mile>(140), si::time<si::hour>(2));
   Velocity AUTO v3 = quantity_cast<si::metre_per_second>(v2);
   Velocity AUTO v4 = quantity_cast<int>(v3);
 
diff --git a/src/include/units/physical/si/area.h b/src/include/units/physical/si/area.h
index 4a53594d..fcfd83a8 100644
--- a/src/include/units/physical/si/area.h
+++ b/src/include/units/physical/si/area.h
@@ -34,7 +34,6 @@ struct dim_area : physical::dim_area<dim_area, square_metre, dim_length> {};
 struct square_millimetre : deduced_unit<square_millimetre, dim_area, millimetre> {};
 struct square_centimetre : deduced_unit<square_centimetre, dim_area, centimetre> {};
 struct square_kilometre : deduced_unit<square_kilometre, dim_area, kilometre> {};
-struct square_foot : deduced_unit<square_foot, dim_area, foot> {};
 
 template<Unit U, Scalar Rep = double>
 using area = quantity<dim_area, U, Rep>;
@@ -57,10 +56,6 @@ constexpr auto operator"" sq_cm(long double l) { return area<square_centimetre,
 constexpr auto operator"" sq_km(unsigned long long l) { return area<square_kilometre, std::int64_t>(l); }
 constexpr auto operator"" sq_km(long double l) { return area<square_kilometre, long double>(l); }
 
-// sq_ft
-constexpr auto operator"" sq_ft(unsigned long long l) { return area<square_foot, std::int64_t>(l); }
-constexpr auto operator"" sq_ft(long double l) { return area<square_foot, long double>(l); }
-
 }  // namespace literals
 
 }  // namespace units::si
diff --git a/src/include/units/physical/si/length.h b/src/include/units/physical/si/length.h
index 6bf17294..92ecb960 100644
--- a/src/include/units/physical/si/length.h
+++ b/src/include/units/physical/si/length.h
@@ -58,30 +58,4 @@ constexpr auto operator"" km(long double l) { return length<kilometre, long doub
 
 }  // namespace literals
 
-// US customary units
-struct yard : named_scaled_unit<yard, "yd", no_prefix, ratio<9'144, 10'000>, metre> {};
-struct foot : named_scaled_unit<foot, "ft", no_prefix, ratio<1, 3>, yard> {};
-struct inch : named_scaled_unit<inch, "in", no_prefix, ratio<1, 12>, foot> {};
-struct mile : named_scaled_unit<mile, "mi", no_prefix, ratio<1'760>, yard> {};
-
-inline namespace literals {
-
-// yd
-constexpr auto operator"" yd(unsigned long long l) { return length<yard, std::int64_t>(l); }
-constexpr auto operator"" yd(long double l) { return length<yard, long double>(l); }
-
-// ft
-constexpr auto operator"" ft(unsigned long long l) { return length<foot, std::int64_t>(l); }
-constexpr auto operator"" ft(long double l) { return length<foot, long double>(l); }
-
-// in
-constexpr auto operator"" in(unsigned long long l) { return length<inch, std::int64_t>(l); }
-constexpr auto operator"" in(long double l) { return length<inch, long double>(l); }
-
-// mi
-constexpr auto operator"" mi(unsigned long long l) { return length<mile, std::int64_t>(l); }
-constexpr auto operator"" mi(long double l) { return length<mile, long double>(l); }
-
-}  // namespace literals
-
 }  // namespace units::si
diff --git a/src/include/units/physical/si/velocity.h b/src/include/units/physical/si/velocity.h
index bcd168bd..f064d61c 100644
--- a/src/include/units/physical/si/velocity.h
+++ b/src/include/units/physical/si/velocity.h
@@ -33,7 +33,6 @@ struct metre_per_second : unit<metre_per_second> {};
 struct dim_velocity : physical::dim_velocity<dim_velocity, metre_per_second, dim_length, dim_time> {};
 
 struct kilometre_per_hour : deduced_unit<kilometre_per_hour, dim_velocity, kilometre, hour> {};
-struct mile_per_hour : deduced_unit<mile_per_hour, dim_velocity, mile, hour> {};
 
 template<Unit U, Scalar Rep = double>
 using velocity = quantity<dim_velocity, U, Rep>;
@@ -48,10 +47,6 @@ constexpr auto operator"" mps(long double l) { return velocity<metre_per_second,
 constexpr auto operator"" kmph(unsigned long long l) { return velocity<kilometre_per_hour, std::int64_t>(l); }
 constexpr auto operator"" kmph(long double l) { return velocity<kilometre_per_hour, long double>(l); }
 
-// mph
-constexpr auto operator"" mph(unsigned long long l) { return velocity<mile_per_hour, std::int64_t>(l); }
-constexpr auto operator"" mph(long double l) { return velocity<mile_per_hour, long double>(l); }
-
 }  // namespace literals
 
 }  // namespace units::si
diff --git a/src/include/units/physical/si/volume.h b/src/include/units/physical/si/volume.h
index be80331a..adef97bd 100644
--- a/src/include/units/physical/si/volume.h
+++ b/src/include/units/physical/si/volume.h
@@ -34,7 +34,6 @@ struct dim_volume : physical::dim_volume<dim_volume, cubic_metre, dim_length> {}
 struct cubic_millimetre : deduced_unit<cubic_millimetre, dim_volume, millimetre> {};
 struct cubic_centimetre : deduced_unit<cubic_centimetre, dim_volume, centimetre> {};
 struct cubic_kilometre : deduced_unit<cubic_kilometre, dim_volume, kilometre> {};
-struct cubic_foot : deduced_unit<cubic_foot, dim_volume, foot> {};
 
 template<Unit U, Scalar Rep = double>
 using volume = quantity<dim_volume, U, Rep>;
@@ -57,10 +56,6 @@ constexpr auto operator""cub_m(long double l) { return volume<cubic_metre, long
 constexpr auto operator""cub_km(unsigned long long l) { return volume<cubic_kilometre, std::int64_t>(l); }
 constexpr auto operator""cub_km(long double l) { return volume<cubic_kilometre, long double>(l); }
 
-// cub_ft
-constexpr auto operator""cub_ft(unsigned long long l) { return volume<cubic_foot, std::int64_t>(l); }
-constexpr auto operator""cub_ft(long double l) { return volume<cubic_foot, long double>(l); }
-
 }  // namespace literals
 
 }  // namespace units::si
diff --git a/src/include/units/physical/us/area.h b/src/include/units/physical/us/area.h
new file mode 100644
index 00000000..0d723af3
--- /dev/null
+++ b/src/include/units/physical/us/area.h
@@ -0,0 +1,40 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+#include <units/physical/si/area.h>
+#include <units/physical/us/length.h>
+
+namespace units::us {
+
+struct square_foot : deduced_unit<square_foot, si::dim_area, foot> {};
+
+inline namespace literals {
+
+// sq_ft
+constexpr auto operator"" sq_ft(unsigned long long l) { return si::area<square_foot, std::int64_t>(l); }
+constexpr auto operator"" sq_ft(long double l) { return si::area<square_foot, long double>(l); }
+
+}  // namespace literals
+
+}  // namespace units::us
diff --git a/src/include/units/physical/us/length.h b/src/include/units/physical/us/length.h
new file mode 100644
index 00000000..c2ac6509
--- /dev/null
+++ b/src/include/units/physical/us/length.h
@@ -0,0 +1,54 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+#include <units/physical/si/length.h>
+
+namespace units::us {
+
+struct yard : named_scaled_unit<yard, "yd", no_prefix, ratio<9'144, 10'000>, si::metre> {};
+struct foot : named_scaled_unit<foot, "ft", no_prefix, ratio<1, 3>, yard> {};
+struct inch : named_scaled_unit<inch, "in", no_prefix, ratio<1, 12>, foot> {};
+struct mile : named_scaled_unit<mile, "mi", no_prefix, ratio<1'760>, yard> {};
+
+inline namespace literals {
+
+// yd
+constexpr auto operator"" yd(unsigned long long l) { return si::length<yard, std::int64_t>(l); }
+constexpr auto operator"" yd(long double l) { return si::length<yard, long double>(l); }
+
+// ft
+constexpr auto operator"" ft(unsigned long long l) { return si::length<foot, std::int64_t>(l); }
+constexpr auto operator"" ft(long double l) { return si::length<foot, long double>(l); }
+
+// in
+constexpr auto operator"" in(unsigned long long l) { return si::length<inch, std::int64_t>(l); }
+constexpr auto operator"" in(long double l) { return si::length<inch, long double>(l); }
+
+// mi
+constexpr auto operator"" mi(unsigned long long l) { return si::length<mile, std::int64_t>(l); }
+constexpr auto operator"" mi(long double l) { return si::length<mile, long double>(l); }
+
+}  // namespace literals
+
+}  // namespace units::us
diff --git a/src/include/units/physical/us/velocity.h b/src/include/units/physical/us/velocity.h
new file mode 100644
index 00000000..ac5d686f
--- /dev/null
+++ b/src/include/units/physical/us/velocity.h
@@ -0,0 +1,40 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+#include <units/physical/si/velocity.h>
+#include <units/physical/us/length.h>
+
+namespace units::us {
+
+struct mile_per_hour : deduced_unit<mile_per_hour, si::dim_velocity, mile, si::hour> {};
+
+inline namespace literals {
+
+// mph
+constexpr auto operator"" mph(unsigned long long l) { return si::velocity<mile_per_hour, std::int64_t>(l); }
+constexpr auto operator"" mph(long double l) { return si::velocity<mile_per_hour, long double>(l); }
+
+}  // namespace literals
+
+}  // namespace units::us
diff --git a/src/include/units/physical/us/volume.h b/src/include/units/physical/us/volume.h
new file mode 100644
index 00000000..29898cc5
--- /dev/null
+++ b/src/include/units/physical/us/volume.h
@@ -0,0 +1,40 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+#include <units/physical/si/volume.h>
+#include <units/physical/us/length.h>
+
+namespace units::us {
+
+struct cubic_foot : deduced_unit<cubic_foot, si::dim_volume, foot> {};
+
+inline namespace literals {
+
+// cub_ft
+constexpr auto operator""cub_ft(unsigned long long l) { return si::volume<cubic_foot, std::int64_t>(l); }
+constexpr auto operator""cub_ft(long double l) { return si::volume<cubic_foot, long double>(l); }
+
+}  // namespace literals
+
+}  // namespace units::us
diff --git a/test/unit_test/runtime/fmt_units_test.cpp b/test/unit_test/runtime/fmt_units_test.cpp
index 1e721528..72fb7a24 100644
--- a/test/unit_test/runtime/fmt_units_test.cpp
+++ b/test/unit_test/runtime/fmt_units_test.cpp
@@ -26,10 +26,14 @@
 #include "units/physical/si/velocity.h"
 #include "units/physical/si/volume.h"
 #include "units/physical/si/surface_tension.h"
+#include "units/physical/us/area.h"
+#include "units/physical/us/velocity.h"
+#include "units/physical/us/volume.h"
 #include "units/format.h"
 #include <catch2/catch.hpp>
 
 using namespace units::si;
+using namespace units::us;
 
 TEST_CASE("fmt::format on synthesized unit symbols", "[text][fmt]")
 {
diff --git a/test/unit_test/static/CMakeLists.txt b/test/unit_test/static/CMakeLists.txt
index 790ee380..06aa6b1f 100644
--- a/test/unit_test/static/CMakeLists.txt
+++ b/test/unit_test/static/CMakeLists.txt
@@ -33,6 +33,7 @@ add_library(unit_tests_static
     si_cgs_test.cpp
     type_list_test.cpp
     unit_test.cpp
+    us_test.cpp
 )
 target_link_libraries(unit_tests_static
     PRIVATE
diff --git a/test/unit_test/static/si_test.cpp b/test/unit_test/static/si_test.cpp
index 19a3cb8e..724064ab 100644
--- a/test/unit_test/static/si_test.cpp
+++ b/test/unit_test/static/si_test.cpp
@@ -59,13 +59,6 @@ static_assert(10km / 5km == 2);
 static_assert(100mm / 5cm == 2);
 static_assert(10km / 2 == 5km);
 
-static_assert(1yd == 0.9144m);
-static_assert(1yd == 3ft);
-static_assert(1ft == 12in);
-static_assert(1mi == 1760yd);
-
-static_assert(5in + 8cm == 207mm);
-
 static_assert(millimetre::symbol == "mm");
 static_assert(centimetre::symbol == "cm");
 static_assert(kilometre::symbol == "km");
@@ -200,8 +193,6 @@ static_assert(1km / 1s == 1000mps);
 static_assert(1.0km / 1h == 1kmph);
 static_assert(1000.0m / 3600.0s == 1kmph);
 
-static_assert(10.0mi / 2h == 5mph);
-
 static_assert(2kmph * 2h == 4km);
 // static_assert(2kmph * 15min == 500m); // should not compile
 static_assert(2kmph * 15.0min == 500m);
@@ -213,7 +204,6 @@ static_assert(quantity_cast<kilometre>(2000m) / 2kmph == 1h);
 
 static_assert(detail::unit_text<dim_velocity, metre_per_second>() == "m/s");
 static_assert(kilometre_per_hour::symbol == "km/h");
-static_assert(mile_per_hour::symbol == "mi/h");
 
 // acceleration
 
diff --git a/test/unit_test/static/us_test.cpp b/test/unit_test/static/us_test.cpp
new file mode 100644
index 00000000..30bdd9dd
--- /dev/null
+++ b/test/unit_test/static/us_test.cpp
@@ -0,0 +1,59 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#include <units/physical/si/area.h>
+#include <units/physical/si/length.h>
+#include <units/physical/si/velocity.h>
+#include <units/physical/si/volume.h>
+#include <units/physical/us/area.h>
+#include <units/physical/us/length.h>
+#include <units/physical/us/velocity.h>
+#include <units/physical/us/volume.h>
+#include <utility>
+
+namespace {
+
+using namespace units;
+using namespace units::si;
+using namespace units::us;
+
+/* ************** BASE DIMENSIONS **************** */
+
+// length
+
+static_assert(1yd == 0.9144m);
+static_assert(1yd == 3ft);
+static_assert(1ft == 12in);
+static_assert(1mi == 1760yd);
+
+static_assert(5in + 8cm == 207mm);
+
+
+/* ************** DERIVED DIMENSIONS IN TERMS OF BASE UNITS **************** */
+
+// velocity
+
+static_assert(10.0mi / 2h == 5mph);
+
+static_assert(mile_per_hour::symbol == "mi/h");
+
+}  // namespace