Index: /applications/editors/josm/plugins/graphview/src/org/openstreetmap/josm/plugins/graphview/core/property/RoadMaxspeed.java
===================================================================
--- /applications/editors/josm/plugins/graphview/src/org/openstreetmap/josm/plugins/graphview/core/property/RoadMaxspeed.java	(revision 36269)
+++ /applications/editors/josm/plugins/graphview/src/org/openstreetmap/josm/plugins/graphview/core/property/RoadMaxspeed.java	(revision 36270)
@@ -1,4 +1,6 @@
 // License: GPL. For details, see LICENSE file.
 package org.openstreetmap.josm.plugins.graphview.core.property;
+
+import java.util.Objects;
 
 import org.openstreetmap.josm.plugins.graphview.core.access.AccessParameters;
@@ -34,5 +36,6 @@
     public <N, W, R, M> Float evaluateN(N node, AccessParameters accessParameters,
             DataSource<N, W, R, M> dataSource) {
-        assert node != null && accessParameters != null && dataSource != null;
+        Objects.requireNonNull(node);
+        Objects.requireNonNull(dataSource);
 
         initializeIfNecessary(dataSource);
@@ -44,5 +47,6 @@
     public <N, W, R, M> Float evaluateW(W way, boolean forward, AccessParameters accessParameters,
             DataSource<N, W, R, M> dataSource) {
-        assert way != null && accessParameters != null && dataSource != null;
+        Objects.requireNonNull(dataSource);
+        Objects.requireNonNull(way);
 
         initializeIfNecessary(dataSource);
@@ -55,10 +59,5 @@
 
         if (maxspeedString != null) {
-
-            Float maxspeed = ValueStringParser.parseSpeed(maxspeedString);
-            if (maxspeed != null) {
-                return maxspeed;
-            }
-
+            return ValueStringParser.parseSpeed(maxspeedString);
         }
 
@@ -68,6 +67,5 @@
     @Override
     public boolean isUsable(Object propertyValue, AccessParameters accessParameters) {
-        assert propertyValue instanceof Float;
-        return true;
+        return propertyValue instanceof Float;
     }