diff --git a/src/main/java/com/conveyal/analysis/results/MultiOriginAssembler.java b/src/main/java/com/conveyal/analysis/results/MultiOriginAssembler.java
index dc2b0b150..6aa3c9fad 100644
--- a/src/main/java/com/conveyal/analysis/results/MultiOriginAssembler.java
+++ b/src/main/java/com/conveyal/analysis/results/MultiOriginAssembler.java
@@ -139,7 +139,8 @@ public MultiOriginAssembler (RegionalAnalysis regionalAnalysis, Job job, FileSto
                     // We might want to record a grid of dual accessibility values, but this will require some serious
                     // refactoring of the GridResultWriter.
                     // if (job.templateTask.dualAccessibilityThreshold > 0) { ... }
-                    throw new IllegalArgumentException("Temporal density of opportunities cannot be recorded for gridded origin points.");
+                    // throw new IllegalArgumentException("Temporal density of opportunities cannot be recorded for " +
+                    //        "gridded origin points.");
                 } else {
                     // Freeform origins.
                     // Output includes temporal density of opportunities and optionally dual accessibility.
diff --git a/src/main/java/com/conveyal/r5/analyst/TemporalDensityResult.java b/src/main/java/com/conveyal/r5/analyst/TemporalDensityResult.java
index 6ba2294b4..573dd9075 100644
--- a/src/main/java/com/conveyal/r5/analyst/TemporalDensityResult.java
+++ b/src/main/java/com/conveyal/r5/analyst/TemporalDensityResult.java
@@ -1,6 +1,7 @@
 package com.conveyal.r5.analyst;
 
 import com.conveyal.r5.analyst.cluster.AnalysisWorkerTask;
+import com.conveyal.r5.analyst.cluster.RegionalTask;
 import com.google.common.base.Preconditions;
 
 import static com.conveyal.r5.common.Util.notNullOrEmpty;
@@ -89,6 +90,36 @@ public int[][] minutesToReachOpportunities(int n) {
         return result;
     }
 
+    public int[][][] fakeDualAccess (RegionalTask task) {
+        int nPointSets = task.destinationPointSets.length;
+        int nCutoffs = task.cutoffsMinutes.length;
+        int[][][] dualAccess = new int[nPointSets][nPercentiles][nCutoffs];
+        for (int d = 0; d < nPointSets; d++) {
+            for (int p = 0; p < nPercentiles; p++) {
+                // Hack: use cutoffs as dual access thresholds
+                for (int c = 0; c < nCutoffs - 1; c++) {
+                    int m = 0;
+                    double sum = 0;
+                    while (sum < task.cutoffsMinutes[c] && m < 120) {
+                        sum += opportunitiesPerMinute[d][p][m];
+                        m += 1;
+                    }
+                    dualAccess[d][p][c] = m == 0 ? 999 : m;
+                }
+                // But hack above won't allow thresholds over 120; so use the dualAccessibilityThreshold instead of
+                // the last cutoff
+                int m = 0;
+                double sum = 0;
+                while (sum < task.dualAccessibilityThreshold && m < 120) {
+                    sum += opportunitiesPerMinute[d][p][m];
+                    m += 1;
+                }
+                dualAccess[d][p][nCutoffs - 1] = m == 0 ? 999 : m;
+            }
+        }
+        return dualAccess;
+    }
+
     public int[][] minutesToReachOpportunities() {
         return minutesToReachOpportunities(opportunityThreshold);
     }
diff --git a/src/main/java/com/conveyal/r5/analyst/TravelTimeReducer.java b/src/main/java/com/conveyal/r5/analyst/TravelTimeReducer.java
index 213091d56..a4d5c50b2 100644
--- a/src/main/java/com/conveyal/r5/analyst/TravelTimeReducer.java
+++ b/src/main/java/com/conveyal/r5/analyst/TravelTimeReducer.java
@@ -145,7 +145,7 @@ public TravelTimeReducer (AnalysisWorkerTask task, TransportNetwork network) {
         if (task.includePathResults) {
             pathResult = new PathResult(task, network.transitLayer);
         }
-        if (task.includeTemporalDensity) {
+        if (task.includeTemporalDensity || task.flags.contains("gridDualAccess")) {
             temporalDensityResult = new TemporalDensityResult(task);
         }
 
diff --git a/src/main/java/com/conveyal/r5/analyst/cluster/RegionalWorkResult.java b/src/main/java/com/conveyal/r5/analyst/cluster/RegionalWorkResult.java
index c606acc0f..7f10e77b8 100644
--- a/src/main/java/com/conveyal/r5/analyst/cluster/RegionalWorkResult.java
+++ b/src/main/java/com/conveyal/r5/analyst/cluster/RegionalWorkResult.java
@@ -63,7 +63,7 @@ public RegionalWorkResult(OneOriginResult result, RegionalTask task) {
         this.jobId = task.jobId;
         this.taskId = task.taskId;
         this.travelTimeValues = result.travelTimes == null ? null : result.travelTimes.values;
-        this.accessibilityValues = result.accessibility == null ? null : result.accessibility.getIntValues();
+        this.accessibilityValues = result.accessibility == null ? null : result.density.fakeDualAccess(task);
         this.pathResult = result.paths == null ? null : result.paths.summarizeIterations(PathResult.Stat.MINIMUM);
         this.opportunitiesPerMinute = result.density == null ? null : result.density.opportunitiesPerMinute;
         // TODO checkTravelTimeInvariants, checkAccessibilityInvariants to verify that values are monotonically increasing