diff --git a/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Edge.java b/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Edge.java
index de2a5c4b..66c85b12 100644
--- a/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Edge.java
+++ b/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Edge.java
@@ -5,6 +5,10 @@ public class Edge extends Capability {
     public String getWebDriverClass() {
         return "org.openqa.selenium.edge.EdgeDriver";
     }
+    
+    public Edge() {
+        this.put("maxInstances", 1);
+    }
 
     @Override
     public String getIcon() {
diff --git a/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Safari.java b/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Safari.java
index 4f306e82..624654ef 100644
--- a/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Safari.java
+++ b/SeleniumGridExtras/src/main/java/com/groupon/seleniumgridextras/config/capabilities/Safari.java
@@ -6,6 +6,10 @@ public class Safari extends Capability {
   public String getWebDriverClass() {
     return "org.openqa.selenium.safari.SafariDriver";
   }
+  
+  public Safari() {
+    this.put("maxInstances", 1);
+  }
 
   @Override
   public String getIcon() {