diff --git a/docs-gen/content/bus_tree/_index.md b/docs-gen/content/bus_tree/_index.md
new file mode 100644
index 0000000..040d76a
--- /dev/null
+++ b/docs-gen/content/bus_tree/_index.md
@@ -0,0 +1,13 @@
+---
+title: Bus tree
+weight: 20
+chapter: true
+---
+
+# The bus tree
+The vspec bus tree is a super tree that contains signal definitions for a large set of different bus models.
+The HIM configurator is then used to create a signal tee for a specific bus variant.
+
+The different bus variants that are present in the vspec files are:
+* xxx
+
diff --git a/docs-gen/content/him_configurator/_index.md b/docs-gen/content/him_configurator/_index.md
index a6e471c..2d7c040 100644
--- a/docs-gen/content/him_configurator/_index.md
+++ b/docs-gen/content/him_configurator/_index.md
@@ -58,3 +58,14 @@ If not used the default is false, i. e. not to save the files.
 The -e command line option is used to substitute the external datatype references with the actual enum definitions
 from the common Datatypes tree in the tree(s) that the VSS-tools generate.
 
+## Creation of a vehicle variant specific signal tree
+The HIM configurator enables a model where a "super tree" covering all variations of a vehicle archetype
+(like Truck, Trailer, Bus, etc) can be defined in the vspec files,
+then the HIM configurator can be used to create a "variant specific" vehicle signal tree via the input data in the himConfiguration.json file.
+
+## Usage of a vehicle variant specific signal tree
+The output from the HIM configurator is the selected parts of the "vspec super tree" in a file with one of the supported formats.
+This file can then e. g. be used in a vehicle of the selected variant by a server that is controlling the access to the signals.
+The server cn then use the tree to "vet" client request - checking that the signal is present, whether it is read-only or read-write, etc.
+An example of a server using it like this is the [VISS reference server](https://github.com/COVESA/vissr).
+
diff --git a/docs-gen/content/tractor_tree/_index.md b/docs-gen/content/tractor_tree/_index.md
deleted file mode 100644
index 4e12a75..0000000
--- a/docs-gen/content/tractor_tree/_index.md
+++ /dev/null
@@ -1,9 +0,0 @@
----
-title: Tractor tree
-weight: 20
-chapter: true
----
-
-# Heavyduty tractor tree
-
-xx...
diff --git a/docs-gen/content/trailer_tree/_index.md b/docs-gen/content/trailer_tree/_index.md
index 04ff07d..07536f6 100644
--- a/docs-gen/content/trailer_tree/_index.md
+++ b/docs-gen/content/trailer_tree/_index.md
@@ -4,6 +4,14 @@ weight: 20
 chapter: true
 ---
 
-# Heavyduty trailer tree
+# The trailer tree
+The vspec trailer tree is a super tree that contains signal definitions for a large set of different trailer models.
+The HIM configurator is then used to create a signal tee for a specific trailer variant.
+
+The different variants that are present in the vspec files are:
+* Flatbed trailer: This trailer type has an open flat bed cargo unit.
+* Box trailer: This trailer type has a cargo unit that is covered by walls and a roof.
+* Tanker trailer: This trailer type has a cargo unit that is specicialized for carrying liquid cargos.
+* Freezer trailer: This trailer type has a cargo unit that is specicialized for carrying cargos that require cooling.
+* Specialized trailer: This trailer type has a cargo unit that does not match with any of the other types...
 
-xxx...
diff --git a/docs-gen/content/truck_tree/_index.md b/docs-gen/content/truck_tree/_index.md
new file mode 100644
index 0000000..68ae501
--- /dev/null
+++ b/docs-gen/content/truck_tree/_index.md
@@ -0,0 +1,17 @@
+---
+title: Truck tree
+weight: 20
+chapter: true
+---
+
+# The truck tree
+The vspec truck tree is a super tree that contains signal definitions for a large set of different truck models.
+The HIM configurator is then used to create a signal tee for a specific truck variant.
+
+The different variants that are present in the vspec files are:
+* Tow truck: This truck type does not have an integrated cargo unit, but instead it is temporarily connected to a trailer (which defines its own signal tree).
+* Flatbed truck: This truck type has an open flat bed cargo unit that is integrated with the rest of the truck.
+* Box truck: This truck type has a cargo unit that is covered by walls and a roof that is integrated with the rest of the truck.
+* Pickup truck: The model would support pickup trucks to be defined here also...
+* Van: The model would support vans to be defined here also...
+
diff --git a/docs-gen/content/truck_tree/driver_tree/_index.md b/docs-gen/content/truck_tree/driver_tree/_index.md
new file mode 100644
index 0000000..ea21933
--- /dev/null
+++ b/docs-gen/content/truck_tree/driver_tree/_index.md
@@ -0,0 +1,13 @@
+---
+title: Driver tree
+weight: 20
+chapter: true
+---
+
+# The driver tree
+The vspec driver tree is used to represent the truck driver data.
+The source for this driver data is the truck dirver recording unit (in europe often named tachograph, in the US xxx).
+As the driver recording unit may hold data not only for the current driver but also for previous drivers,
+there might be several instances of this driver tree, one for each driver that the driver recording unit has a record on.
+The data from these different instances should be accessible via the interface that is exposed by vehicle server managing the access to the driver recording device.
+
diff --git a/docs-gen/themes/learn/static/css/theme.css b/docs-gen/themes/learn/static/css/theme.css
index 98a5584..969a07d 100644
--- a/docs-gen/themes/learn/static/css/theme.css
+++ b/docs-gen/themes/learn/static/css/theme.css
@@ -429,14 +429,14 @@ textarea:focus, input[type="email"]:focus, input[type="number"]:focus, input[typ
 #chapter h3 {
     font-family: "Work Sans", "Helvetica", "Tahoma", "Geneva", "Arial", sans-serif;
     font-weight: 300;
-    text-align: center;
+    text-align: left;
 }
 #chapter h1 {
     font-size: 5rem;
     border-bottom: 4px solid #F0F2F4;
 }
 #chapter p {
-    text-align: center;
+    text-align: left;
     font-size: 1.2rem;
 }
 #footer {
@@ -462,7 +462,7 @@ h2, h3, h4, h5, h6 {
 }
 h1 {
     font-family: "Novacento Sans Wide", "Helvetica", "Tahoma", "Geneva", "Arial", sans-serif;
-    text-align: center;
+    text-align: left;
     text-transform: uppercase;
     color: #222;
     font-weight: 200;
diff --git a/spec/trees/Vehicle/Trailer/Cargo/BoxCargo.vspec b/spec/trees/Vehicle/Trailer/Cargo/BoxCargo.vspec
new file mode 100755
index 0000000..0ed109a
--- /dev/null
+++ b/spec/trees/Vehicle/Trailer/Cargo/BoxCargo.vspec
@@ -0,0 +1,15 @@
+# Copyright (c) 2016 Contributors to COVESA
+#
+# This program and the accompanying materials are made available under the
+# terms of the Mozilla Public License 2.0 which is available at
+# https://www.mozilla.org/en-US/MPL/2.0/
+#
+# SPDX-License-Identifier: MPL-2.0
+
+#
+# Box type trailer cargo signals and attributes
+#
+
+BoxCargo:
+  type: branch
+  description: Box type trailer.
diff --git a/spec/trees/Vehicle/Trailer/Cargo/Cargo.vspec b/spec/trees/Vehicle/Trailer/Cargo/Cargo.vspec
new file mode 100755
index 0000000..7f419eb
--- /dev/null
+++ b/spec/trees/Vehicle/Trailer/Cargo/Cargo.vspec
@@ -0,0 +1,22 @@
+# Copyright (c) 2016 Contributors to COVESA
+#
+# This program and the accompanying materials are made available under the
+# terms of the Mozilla Public License 2.0 which is available at
+# https://www.mozilla.org/en-US/MPL/2.0/
+#
+# SPDX-License-Identifier: MPL-2.0
+
+#
+# Trailer cargo signals and attributes
+#
+
+Cargo:
+  type: branch
+  description: Trailer cargo types.
+
+VariationPoint: #CargoType
+  - BOXCARGO  #include BoxCargo.vspec Cargo
+  - FLATBEDCARGO #include FlatbedCargo.vspec Cargo
+  - TANKERCARGO #include TankerCargo.vspec Cargo
+  - FREEZERCARGO #include FreezerCargo.vspec Cargo
+  - SPECIALIZEDCARGO #include SpecializedCargo.vspec Cargo
diff --git a/spec/trees/Vehicle/Trailer/Body/Flatbed/FlatbedCargo.vspec b/spec/trees/Vehicle/Trailer/Cargo/FlatbedCargo.vspec
similarity index 77%
rename from spec/trees/Vehicle/Trailer/Body/Flatbed/FlatbedCargo.vspec
rename to spec/trees/Vehicle/Trailer/Cargo/FlatbedCargo.vspec
index f01077b..8131680 100755
--- a/spec/trees/Vehicle/Trailer/Body/Flatbed/FlatbedCargo.vspec
+++ b/spec/trees/Vehicle/Trailer/Cargo/FlatbedCargo.vspec
@@ -7,9 +7,9 @@
 # SPDX-License-Identifier: MPL-2.0
 
 #
-# Flatbed truck cargo signals and attributes
+# Flatbed trailer type cargo signals and attributes
 #
 
 FlatbedCargo:
   type: branch
-  description: Flatbed truck cargo signals.
+  description: Flatbed trailer type.
diff --git a/spec/trees/Vehicle/Trailer/Body/Freezer/FreezerCargo.vspec b/spec/trees/Vehicle/Trailer/Cargo/FreezerCargo.vspec
similarity index 77%
rename from spec/trees/Vehicle/Trailer/Body/Freezer/FreezerCargo.vspec
rename to spec/trees/Vehicle/Trailer/Cargo/FreezerCargo.vspec
index be63629..5ba5429 100755
--- a/spec/trees/Vehicle/Trailer/Body/Freezer/FreezerCargo.vspec
+++ b/spec/trees/Vehicle/Trailer/Cargo/FreezerCargo.vspec
@@ -7,9 +7,9 @@
 # SPDX-License-Identifier: MPL-2.0
 
 #
-# Freezer truck cargo signals and attributes
+# Freezer trailer type cargo signals and attributes
 #
 
 FreezerCargo:
   type: branch
-  description: Freezer truck cargo signals.
+  description: Freezer trailer type.
diff --git a/spec/trees/Vehicle/Trailer/Body/Specialized/SpecializedCargo.vspec b/spec/trees/Vehicle/Trailer/Cargo/SpecializedCargo.vspec
similarity index 75%
rename from spec/trees/Vehicle/Trailer/Body/Specialized/SpecializedCargo.vspec
rename to spec/trees/Vehicle/Trailer/Cargo/SpecializedCargo.vspec
index 826dc90..3851b4a 100755
--- a/spec/trees/Vehicle/Trailer/Body/Specialized/SpecializedCargo.vspec
+++ b/spec/trees/Vehicle/Trailer/Cargo/SpecializedCargo.vspec
@@ -7,9 +7,9 @@
 # SPDX-License-Identifier: MPL-2.0
 
 #
-# Specialized truck cargo signals and attributes
+# Specialized trailr type cargo signals and attributes
 #
 
 SpecializedCargo:
   type: branch
-  description: Specialized truck cargo signals.
+  description: Specialized trailer type.
diff --git a/spec/trees/Vehicle/Trailer/Body/Tanker/TankerCargo.vspec b/spec/trees/Vehicle/Trailer/Cargo/TankerCargo.vspec
similarity index 77%
rename from spec/trees/Vehicle/Trailer/Body/Tanker/TankerCargo.vspec
rename to spec/trees/Vehicle/Trailer/Cargo/TankerCargo.vspec
index d10c306..369c84f 100755
--- a/spec/trees/Vehicle/Trailer/Body/Tanker/TankerCargo.vspec
+++ b/spec/trees/Vehicle/Trailer/Cargo/TankerCargo.vspec
@@ -7,9 +7,9 @@
 # SPDX-License-Identifier: MPL-2.0
 
 #
-# Tanker truck cargo signals and attributes
+# Tanker trailer type cargo signals and attributes
 #
 
 TankerCargo:
   type: branch
-  description: Tanker truck cargo signals.
+  description: Tanker trailer type.
diff --git a/spec/trees/Vehicle/Trailer/TrailerSignalSpecification.vspec b/spec/trees/Vehicle/Trailer/TrailerSignalSpecification.vspec
index d50583a..b716100 100644
--- a/spec/trees/Vehicle/Trailer/TrailerSignalSpecification.vspec
+++ b/spec/trees/Vehicle/Trailer/TrailerSignalSpecification.vspec
@@ -27,10 +27,11 @@ Trailer:
 #include Chassis/Chassis.vspec Trailer
 
 VariationPoint: #TrailerCargoType
-  - FLATBED #include Body/Flatbed/FlatbedCargo.vspec Trailer
-  - TANKER #include Body/Tanker/TankerCargo.vspec Trailer
-  - FREEZER #include Body/Freezer/FreezerCargo.vspec Trailer
-  - SPECIALIZED #include Body/Specialized/SpecializedCargo.vspec Trailer
+  - BOXCARGO #include Cargo/BoxCargo.vspec Trailer
+  - FLATBEDCARGO #include Cargo/FlatbedCargo.vspec Trailer
+  - TANKERCARGO #include Cargo/TankerCargo.vspec Trailer
+  - FREEZERCARGO #include Cargo/FreezerCargo.vspec Trailer
+  - SPECIALIZEDCARGO #include Cargo/SpecializedCargo.vspec Trailer
 
 ##include Exterior/Exterior.vspec Trailer
 
diff --git a/spec/trees/Vehicle/Trailer/Variability.json b/spec/trees/Vehicle/Trailer/Variability.json
index 4b19395..5803459 100644
--- a/spec/trees/Vehicle/Trailer/Variability.json
+++ b/spec/trees/Vehicle/Trailer/Variability.json
@@ -3,6 +3,9 @@
         {
             "FLATBED": "FLATBED"
         },
+        {
+            "BOX": "BOX"
+        },
         {
             "TANKER": "TANKER"
         },
diff --git a/spec/trees/Vehicle/Truck/Cargo/Boxtruck.vspec b/spec/trees/Vehicle/Truck/Cargo/Boxtruck.vspec
index d08f73a..a525331 100755
--- a/spec/trees/Vehicle/Truck/Cargo/Boxtruck.vspec
+++ b/spec/trees/Vehicle/Truck/Cargo/Boxtruck.vspec
@@ -10,6 +10,6 @@
 # Boxtruck cargo signals and attributes
 #
 
-Boxtruck:
+BoxTruck:
   type: branch
-  description: Boxtruck cargo signals.
+  description: Box truck type cargo.
diff --git a/spec/trees/Vehicle/Truck/Cargo/Cargo.vspec b/spec/trees/Vehicle/Truck/Cargo/Cargo.vspec
index 13e8044..2bc8df8 100755
--- a/spec/trees/Vehicle/Truck/Cargo/Cargo.vspec
+++ b/spec/trees/Vehicle/Truck/Cargo/Cargo.vspec
@@ -15,7 +15,8 @@ Cargo:
   description: Truck cargo signals.
 
 VariationPoint: #CargoType
-  - BOXTRUCK  #include Boxtruck.vspec Cargo
   - TOWTRUCK #include TowTruck.vspec Cargo
+  - BOXTRUCK  #include Boxtruck.vspec Cargo
+  - FLATBEDTRUCK #include FlatbedTruck.vspec Cargo
   - VAN #include Van.vspec Cargo
   - PICKUP #include Pickup.vspec Cargo
diff --git a/spec/trees/Vehicle/Truck/Cargo/Flatbedtruck.vspec b/spec/trees/Vehicle/Truck/Cargo/Flatbedtruck.vspec
new file mode 100755
index 0000000..7e06cd3
--- /dev/null
+++ b/spec/trees/Vehicle/Truck/Cargo/Flatbedtruck.vspec
@@ -0,0 +1,15 @@
+# Copyright (c) 2016 Contributors to COVESA
+#
+# This program and the accompanying materials are made available under the
+# terms of the Mozilla Public License 2.0 which is available at
+# https://www.mozilla.org/en-US/MPL/2.0/
+#
+# SPDX-License-Identifier: MPL-2.0
+
+#
+# Flatbed truck cargo signals and attributes
+#
+
+FlatbedTruck:
+  type: branch
+  description: Flatbed truck cargo type.
diff --git a/spec/trees/Vehicle/Truck/Variability.json b/spec/trees/Vehicle/Truck/Variability.json
index 257c605..5b76d03 100644
--- a/spec/trees/Vehicle/Truck/Variability.json
+++ b/spec/trees/Vehicle/Truck/Variability.json
@@ -26,6 +26,9 @@
         {
             "BOXTRUCK": "BOXTRUCK"
         },
+        {
+            "FLATBEDTRUCK": "FLATBEDTRUCK"
+        },
         {
             "PICKUP": "PICKUP"
         },