diff --git a/obd.cabal b/obd.cabal
--- a/obd.cabal
+++ b/obd.cabal
@@ -1,5 +1,5 @@
 name:                obd
-version:             0.2.0.1
+version:             0.2.0.2
 synopsis:            Communicate to OBD interfaces over ELM327
 description:
     Haskell library to communicate with OBD-II over ELM327,
diff --git a/src/System/Hardware/ELM327/OBD/Conversion.hs b/src/System/Hardware/ELM327/OBD/Conversion.hs
--- a/src/System/Hardware/ELM327/OBD/Conversion.hs
+++ b/src/System/Hardware/ELM327/OBD/Conversion.hs
@@ -72,8 +72,8 @@
 -- | Convert vehicle speed
 vehicleSpeed :: Iso' (Velocity Double) OneByte
 vehicleSpeed = iso conv mConv
-  where conv = (^. doubleOneByte) . (/~ (kilo meter / second))
-        mConv = (*~ (kilo meter / second)) . (^. re doubleOneByte)
+  where conv = (^. doubleOneByte) . (/~ (kilo meter / hour))
+        mConv = (*~ (kilo meter / hour)) . (^. re doubleOneByte)
 
 -- | Convert between 'Double' and two bytes.
 doubleTwoBytes :: Iso' Double TwoBytes