diff --git a/java-r5rcore/src/org/ipea/r5r/Network/NetworkBuilder.java b/java-r5rcore/src/org/ipea/r5r/Network/NetworkBuilder.java
index 5d0631cd..26fb164b 100644
--- a/java-r5rcore/src/org/ipea/r5r/Network/NetworkBuilder.java
+++ b/java-r5rcore/src/org/ipea/r5r/Network/NetworkBuilder.java
@@ -3,6 +3,7 @@
 import com.conveyal.analysis.datasource.DataSourceException;
 import com.conveyal.gtfs.GTFSFeed;
 import com.conveyal.osmlib.OSM;
+import com.conveyal.r5.analyst.cluster.TransportNetworkConfig;
 import com.conveyal.r5.analyst.scenario.RasterCost;
 import com.conveyal.r5.kryo.KryoNetworkSerializer;
 import com.conveyal.r5.streets.StreetLayer;
@@ -21,6 +22,7 @@
 import java.util.stream.Stream;
 
 public class NetworkBuilder {
+    public static final String JSON_CONFIG_FILE = "config.json";
 
     public static boolean useNativeElevation = false;
     public static String elevationCostFunction = "NONE";
@@ -31,6 +33,8 @@ public class NetworkBuilder {
     private static OSM osmFile;
     private static Stream<GTFSFeed> gtfsFeeds;
     private static String tiffFile = "";
+    private static TransportNetworkConfig transportNetworkConfig = null;
+
 
     public static TransportNetwork checkAndLoadR5Network(String dataFolder) throws Exception {
         File file = new File(dataFolder, "network.dat");
@@ -102,6 +106,8 @@ private static Map<String, String> buildNetworkConfig() {
         networkConfig.put("elevation_cost_function", elevationCostFunction);
         networkConfig.put("tiff_file_name", tiffFile);
 
+        networkConfig.put("transportNetworkConfig", transportNetworkConfig != null ? JSON_CONFIG_FILE : null);
+
         return networkConfig;
     }
 
@@ -109,13 +115,14 @@ private static TransportNetwork createNetwork() {
         TransportNetwork network = new TransportNetwork();
 
         network.scenarioId = "r5r";
-        network.streetLayer = new StreetLayer();
+        network.streetLayer = new StreetLayer(transportNetworkConfig);
         network.streetLayer.loadFromOsm(osmFile);
         osmFile.close();
 
         network.streetLayer.parentNetwork = network;
         network.streetLayer.indexStreets();
 
+        // currently the TransitLayer has no config, so we do not pass in networkConfig
         network.transitLayer = new TransitLayerWithShapes();
 
         gtfsFeeds.forEach(gtfsFeed -> {
@@ -185,6 +192,15 @@ public static void loadDirectory(File directory) {
             }
             if (name.endsWith(".zip")) gtfsFiles.add(file.getAbsolutePath());
             if (name.endsWith(".tif") | name.endsWith(".tiff")) tiffFile = file.getAbsolutePath();
+            if (name.equals(JSON_CONFIG_FILE)) {
+                try {
+                    // Use the R5 object mapper to make sure R5 config files are compatible (e.g. same case conventions)
+                    transportNetworkConfig = com.conveyal.analysis.util.JsonUtil.objectMapper.readValue(file, TransportNetworkConfig.class);
+                } catch (Exception e) {
+                    // re-throw, don't silently ignore a config file
+                    throw new RuntimeException(e);
+                }
+            }
         }
 
         // Supply feeds with a stream, so they do not sit open in memory while other feeds are being processed.
diff --git a/r-package/R/utils.R b/r-package/R/utils.R
index b45f6a04..c1fcba31 100644
--- a/r-package/R/utils.R
+++ b/r-package/R/utils.R
@@ -137,18 +137,27 @@ start_r5r_java <- function(data_path,
   fileurl <- fileurl_from_metadata( r5r_env$r5_jar_version )
   filename <- basename(fileurl)
 
-  jar_file <- data.table::fifelse(
-    temp_dir,
-    file.path(tempdir(), filename),
-    file.path( r5r_env$cache_dir, filename)
-  )
-
-  # If there isn't a JAR already larger than 60MB, download it
-  if (checkmate::test_file_exists(jar_file) && file.info(jar_file)$size > r5r_env$r5_jar_size) {
-    if (!verbose) message("Using cached R5 version from ", jar_file)
+  if (is.null(getOption("r5r.r5jar"))) {
+    jar_file <- data.table::fifelse(
+      temp_dir,
+      file.path(tempdir(), filename),
+      file.path( r5r_env$cache_dir, filename)
+    )
+
+    # If there isn't a JAR already larger than 60MB, download it
+    if (checkmate::test_file_exists(jar_file) && file.info(jar_file)$size > r5r_env$r5_jar_size) {
+      if (!verbose) message("Using cached R5 version from ", jar_file)
+    } else {
+      check  <- download_r5(temp_dir = temp_dir, quiet = !verbose)
+      if (is.null(check)) { return(invisible(NULL)) }
+    }
   } else {
-    check  <- download_r5(temp_dir = temp_dir, quiet = !verbose)
-    if (is.null(check)) { return(invisible(NULL)) }
+    jar_file <- getOption("r5r.r5jar")
+    if (checkmate::test_file_exists(jar_file)) {
+      message("Overriding default R5 with option r5r.r5jar, using ", jar_file)
+    } else {
+      stop(paste0("Cannot find r5 jar \"", jar_file, "\", specified in options(r5r.r5jar)"))
+    }
   }
 
   # R5 jar
diff --git a/r-package/inst/jar/r5r.jar b/r-package/inst/jar/r5r.jar
index b8ebf475..384daad0 100644
Binary files a/r-package/inst/jar/r5r.jar and b/r-package/inst/jar/r5r.jar differ