diff --git a/src/karts/controller/ai_properties.cpp b/src/karts/controller/ai_properties.cpp
index 7c0c75b2a..b4c22e8e9 100644
--- a/src/karts/controller/ai_properties.cpp
+++ b/src/karts/controller/ai_properties.cpp
@@ -26,9 +26,6 @@ float AIProperties::UNDEFINED = -99.9f;
 /** Constructor. Sets all properties to the special UNDEFINED value.
  */
 AIProperties::AIProperties(RaceManager::Difficulty difficulty)
-            : m_skid_probability(/*decreasing*/false)
-            , m_speed_cap(/*decreasing*/true)
-            , m_collect_item_probability(/*decreasing*/true)
 {
     switch(difficulty)
     {
diff --git a/src/karts/kart_properties.cpp b/src/karts/kart_properties.cpp
index b2fd3e67f..46999bf29 100644
--- a/src/karts/kart_properties.cpp
+++ b/src/karts/kart_properties.cpp
@@ -44,7 +44,6 @@ float KartProperties::UNDEFINED = -99.9f;
  *  defined, it is guaranteed that each kart has well defined physics values).
  */
 KartProperties::KartProperties(const std::string &filename)
-              : m_turn_angle_at_speed(/*decreasing*/true)
 {
     m_icon_material = NULL;
     m_minimap_icon  = NULL;
diff --git a/src/utils/interpolation_array.hpp b/src/utils/interpolation_array.hpp
index 70212f748..9ed7c8cac 100644
--- a/src/utils/interpolation_array.hpp
+++ b/src/utils/interpolation_array.hpp
@@ -40,11 +40,8 @@ private:
     /* Pre-computed (x[i+1]-x[i])/(y[i+1]/-y[i]) . */
     std::vector<float> m_delta;
 
-    /** True if the Y values are decreasing. This flag is important when 
-     *  doing a reverse loopup (find X given Y). */
-    bool m_decreasing;
 public:
-    InterpolationArray(bool decreasing) : m_decreasing(decreasing) {};
+    InterpolationArray() {};
 
     /** Adds the value pair x/y to the list of all points. It is tested
      *  that the x values are added in order.
@@ -114,7 +111,7 @@ public:
     {
         if(m_y.size()==1) return m_x[0];
 
-        if(m_decreasing)
+        if(m_y[1]<m_y[0])   // if decreasing values
         {
             if(y > m_y[0]) return m_x[0];