diff --git a/modules/common/src/main/java/edu/tigers/sumatra/drawable/ShapeMap.java b/modules/common/src/main/java/edu/tigers/sumatra/drawable/ShapeMap.java
index 9ff5be7b..ac6e32f5 100644
--- a/modules/common/src/main/java/edu/tigers/sumatra/drawable/ShapeMap.java
+++ b/modules/common/src/main/java/edu/tigers/sumatra/drawable/ShapeMap.java
@@ -15,6 +15,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 
 /**
@@ -169,7 +170,7 @@ private ShapeLayer()
 		public ShapeLayer(final IShapeLayerIdentifier identifier)
 		{
 			this.identifier = identifier;
-			shapes = new ArrayList<>();
+			shapes = new CopyOnWriteArrayList<>();
 		}