Five cucumber tests fail where routing should prefer turning facilities (turning_circle, turning_loop, mini_roundabout) for u-turns but instead chooses direct u-turns.

Root Cause

The Lua profile code in profiles/lib/obstacles.lua was attempting to lookup obstacle types using obstacle_type[highway] where highway is a string value (e.g., "turning_circle"). However, Sol2's new_enum() function creates an enum table with named fields (e.g., obstacle_type.turning_circle) but doesn't automatically support string-indexed lookups (obstacle_type["turning_circle"]).

This caused turning facilities to never be added to the obstacle map, resulting in the routing algorithm not recognizing them and applying u-turn penalties even when using designated turning facilities.

Solution

Added an explicit mapping table highway_to_obstacle_type in profiles/lib/obstacles.lua that maps highway tag string values to their corresponding obstacle type enum values:

local highway_to_obstacle_type = {
    ["traffic_signals"] = obstacle_type.traffic_signals,
    ["stop"] = obstacle_type.stop,
    ["give_way"] = obstacle_type.give_way,
    ["crossing"] = obstacle_type.crossing,
    ["traffic_calming"] = obstacle_type.traffic_calming,
    ["mini_roundabout"] = obstacle_type.mini_roundabout,
    ["turning_loop"] = obstacle_type.turning_loop,
    ["turning_circle"] = obstacle_type.turning_circle
}

This ensures that nodes with highway=turning_circle, highway=turning_loop, or highway=mini_roundabout are correctly identified and added to the obstacle map during extraction, allowing the routing engine to recognize these facilities and avoid applying u-turn penalties when using them.

Changes Made

• File Modified: profiles/lib/obstacles.lua
  • Added explicit highway_to_obstacle_type mapping table (lines 6-16)
  • Changed lookup from obstacle_type[highway] to highway_to_obstacle_type[highway] (line 23)

Expected Impact

All five failing cucumber test scenarios should now pass:

• Car - Should prefer turning_circle for u-turn over direct u-turn
• Car - U-turn at turning_loop should have no penalty
• Car - U-turn at mini_roundabout should work
• Car - Multiple turning facilities, use closest
• Car - Turning circle on one-way should respect direction