diff --git a/OpenRA.Mods.Common/Activities/FindAndDeliverResources.cs b/OpenRA.Mods.Common/Activities/FindAndDeliverResources.cs
index 7f729637eb..7d86ed8120 100644
--- a/OpenRA.Mods.Common/Activities/FindAndDeliverResources.cs
+++ b/OpenRA.Mods.Common/Activities/FindAndDeliverResources.cs
@@ -24,7 +24,6 @@ namespace OpenRA.Mods.Common.Activities
 		readonly HarvesterInfo harvInfo;
 		readonly Mobile mobile;
 		readonly ResourceClaimLayer claimLayer;
-		readonly DomainIndex domainIndex;
 
 		Actor deliverActor;
 		CPos? orderLocation;
@@ -41,7 +40,6 @@ namespace OpenRA.Mods.Common.Activities
 			harvInfo = self.Info.TraitInfo<HarvesterInfo>();
 			mobile = self.Trait<Mobile>();
 			claimLayer = self.World.WorldActor.Trait<ResourceClaimLayer>();
-			domainIndex = self.World.WorldActor.Trait<DomainIndex>();
 			this.deliverActor = deliverActor;
 		}
 
@@ -188,7 +186,6 @@ namespace OpenRA.Mods.Common.Activities
 			using (var search = PathSearch.ToTargetCellByPredicate(
 				self.World, mobile.Locomotor, self, new[] { searchFromLoc, self.Location },
 				loc =>
-					domainIndex.IsPassable(self.Location, loc, mobile.Locomotor) &&
 					harv.CanHarvestCell(self, loc) &&
 					claimLayer.CanClaimCell(self, loc),
 				BlockedByActor.Stationary,
diff --git a/OpenRA.Mods.Common/Activities/Move/MoveAdjacentTo.cs b/OpenRA.Mods.Common/Activities/Move/MoveAdjacentTo.cs
index a3bcf19b31..450ce9719b 100644
--- a/OpenRA.Mods.Common/Activities/Move/MoveAdjacentTo.cs
+++ b/OpenRA.Mods.Common/Activities/Move/MoveAdjacentTo.cs
@@ -22,7 +22,6 @@ namespace OpenRA.Mods.Common.Activities
 	public class MoveAdjacentTo : Activity
 	{
 		protected readonly Mobile Mobile;
-		readonly DomainIndex domainIndex;
 		readonly Color? targetLineColor;
 
 		protected Target Target => useLastVisibleTarget ? lastVisibleTarget : target;
@@ -37,7 +36,6 @@ namespace OpenRA.Mods.Common.Activities
 			this.target = target;
 			this.targetLineColor = targetLineColor;
 			Mobile = self.Trait<Mobile>();
-			domainIndex = self.World.WorldActor.Trait<DomainIndex>();
 			ChildHasPriority = false;
 
 			// The target may become hidden between the initial order request and the first tick (e.g. if queued)
@@ -123,7 +121,7 @@ namespace OpenRA.Mods.Common.Activities
 				searchCells.Clear();
 				searchCellsTick = self.World.WorldTick;
 				foreach (var cell in CandidateMovementCells(self))
-					if (domainIndex.IsPassable(loc, cell, Mobile.Locomotor) && Mobile.CanEnterCell(cell))
+					if (Mobile.CanEnterCell(cell))
 						searchCells.Add(cell);
 			}
 
diff --git a/OpenRA.Mods.Common/Scripting/Global/ReinforcementsGlobal.cs b/OpenRA.Mods.Common/Scripting/Global/ReinforcementsGlobal.cs
index 5434734ac0..27c6bb3523 100644
--- a/OpenRA.Mods.Common/Scripting/Global/ReinforcementsGlobal.cs
+++ b/OpenRA.Mods.Common/Scripting/Global/ReinforcementsGlobal.cs
@@ -25,12 +25,9 @@ namespace OpenRA.Mods.Common.Scripting
 	[ScriptGlobal("Reinforcements")]
 	public class ReinforcementsGlobal : ScriptGlobal
 	{
-		readonly DomainIndex domainIndex;
-
 		public ReinforcementsGlobal(ScriptContext context)
 			: base(context)
 		{
-			domainIndex = context.World.WorldActor.Trait<DomainIndex>();
 		}
 
 		Actor CreateActor(Player owner, string actorType, bool addToWorld, CPos? entryLocation = null, CPos? nextLocation = null)
diff --git a/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs
index 7133ff8bfc..b48f0db0c7 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs
@@ -62,7 +62,6 @@ namespace OpenRA.Mods.Common.Traits
 		readonly Dictionary<Actor, HarvesterTraitWrapper> harvesters = new Dictionary<Actor, HarvesterTraitWrapper>();
 
 		IPathFinder pathfinder;
-		DomainIndex domainIndex;
 		IResourceLayer resourceLayer;
 		ResourceClaimLayer claimLayer;
 		IBotRequestUnitProduction[] requestUnitProduction;
@@ -84,7 +83,6 @@ namespace OpenRA.Mods.Common.Traits
 		protected override void TraitEnabled(Actor self)
 		{
 			pathfinder = world.WorldActor.Trait<IPathFinder>();
-			domainIndex = world.WorldActor.Trait<DomainIndex>();
 			resourceLayer = world.WorldActor.TraitOrDefault<IResourceLayer>();
 			claimLayer = world.WorldActor.TraitOrDefault<ResourceClaimLayer>();
 
@@ -145,7 +143,6 @@ namespace OpenRA.Mods.Common.Traits
 		Target FindNextResource(Actor actor, HarvesterTraitWrapper harv)
 		{
 			Func<CPos, bool> isValidResource = cell =>
-				domainIndex.IsPassable(actor.Location, cell, harv.Locomotor) &&
 				harv.Harvester.CanHarvestCell(actor, cell) &&
 				claimLayer.CanClaimCell(actor, cell);
 
diff --git a/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs b/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs
index 46b13c92b4..74ab805cd9 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs
@@ -325,8 +325,8 @@ namespace OpenRA.Mods.Common.Traits
 
 			// If this bridge repair operation connects two pathfinding domains,
 			// update the domain index.
-			var domainIndex = self.World.WorldActor.TraitOrDefault<DomainIndex>();
-			domainIndex?.UpdateCells(self.World, footprint.Keys);
+			var domainIndex = self.World.WorldActor.Trait<DomainIndex>();
+			domainIndex.UpdateCells(self.World, footprint.Keys);
 
 			if (LongBridgeSegmentIsDead() && !killedUnits)
 			{
diff --git a/OpenRA.Mods.Common/Traits/Buildings/GroundLevelBridge.cs b/OpenRA.Mods.Common/Traits/Buildings/GroundLevelBridge.cs
index f13e54b308..5b76018841 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/GroundLevelBridge.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/GroundLevelBridge.cs
@@ -71,7 +71,7 @@ namespace OpenRA.Mods.Common.Traits
 			foreach (var cell in cells)
 				self.World.Map.CustomTerrain[cell] = terrainIndex;
 
-			self.World.WorldActor.TraitOrDefault<DomainIndex>()?.UpdateCells(self.World, cells);
+			self.World.WorldActor.Trait<DomainIndex>().UpdateCells(self.World, cells);
 		}
 
 		void INotifyAddedToWorld.AddedToWorld(Actor self)