feat(profiles): handle priority=forward/backward way tag in car profile

features/car/priority.feature

@@ -0,0 +1,24 @@
+@routing @priority @car
+Feature: Car - Priority tag handling
+The priority tag indicates traffic right-of-way direction on a way.
+priority=forward means forward traffic has right-of-way, penalizing backward.
+priority=backward means backward traffic has right-of-way, penalizing forward.
+
+    Background: Use specific speeds
+        Given the profile "car"
+        Given a grid size of 1000 meters
+
+    Scenario: Car - Priority tag applies directional penalty
+        Then routability should be
+            | highway     | maxspeed | priority | forw    | backw   | forw_rate | backw_rate |
+            | primary     | 60       |          | 48 km/h | 48 km/h | 13.3      | 13.3       |
+            | primary     | 60       | forward  | 48 km/h | 48 km/h | 13.3      | 9.3        |
+            | primary     | 60       | backward | 48 km/h | 48 km/h | 9.3       | 13.3       |
+
+    Scenario: Car - Priority penalty applies to the permitted direction on oneways when it lacks priority
+        Then routability should be
+            | highway     | maxspeed | priority | oneway | forw    | backw   | forw_rate | backw_rate |
+            | primary     | 60       | forward  | yes    | 48 km/h |         | 13.3      |            |
+            | primary     | 60       | backward | yes    | 48 km/h |         | 9.3       |            |
+            | primary     | 60       | forward  | -1     |         | 48 km/h |           | 9.3        |
+            | primary     | 60       | backward | -1     |         | 48 km/h |           | 13.3       |

profiles/car.lua

@@ -42,6 +42,9 @@ function setup()
     -- Applied to bidirectional roads to prefer roads with clear lane markings
     lane_markings_penalty     = 0.75,
 
+    -- Penalty multiplier for the non-priority direction on ways tagged priority=forward/backward
+    priority_penalty          = 0.7,
+
     -- Size of the vehicle, to be limited by physical restriction of the way
     vehicle_height = 2.0, -- in meters, 2.0m is the height slightly above biggest SUVs
     vehicle_width = 1.9, -- in meters, ways with narrow tag are considered narrower than 2.2m

profiles/lib/way_handlers.lua

@@ -437,8 +437,19 @@ function WayHandlers.penalties(profile,way,result,data)
     sideroad_penalty = profile.side_road_multiplier
   end
 
-  local forward_penalty = math.min(service_penalty, width_penalty, alternating_penalty, sideroad_penalty)
-  local backward_penalty = math.min(service_penalty, width_penalty, alternating_penalty, sideroad_penalty)
+  local priority_forward_penalty = 1.0
+  local priority_backward_penalty = 1.0
+  if profile.priority_penalty then
+    local priority = way:get_value_by_key("priority")
+    if priority == "forward" then
+      priority_backward_penalty = profile.priority_penalty
+    elseif priority == "backward" then
+      priority_forward_penalty = profile.priority_penalty
+    end
+  end
+
+  local forward_penalty = math.min(service_penalty, width_penalty, alternating_penalty, sideroad_penalty, priority_forward_penalty)
+  local backward_penalty = math.min(service_penalty, width_penalty, alternating_penalty, sideroad_penalty, priority_backward_penalty)
 
   if profile.properties.weight_name == 'routability' then
     if result.forward_speed > 0 then

taginfo.json

@@ -258,6 +258,8 @@
         {"key": "lanes:forward", "description": "Lanes in forward direction"},
         {"key": "lanes:backward", "description": "Lanes in backward direction"},
         {"key": "lane_markings", "value": "no", "description": "Penalty for roads without lane markings on bidirectional streets"},
+        {"key": "priority", "value": "forward", "object_types": ["way"], "description": "Traffic priority in forward direction; non-priority direction gets a penalty"},
+        {"key": "priority", "value": "backward", "object_types": ["way"], "description": "Traffic priority in backward direction; non-priority direction gets a penalty"},
         {"key": "surface", "value": "asphalt"},
         {"key": "surface", "value": "concrete"},
         {"key": "surface", "value": "concrete:plates"},