default int getDirection(String key) {
    return Parse.direction(getTag(key));
  }
Returns the value for {@code key} interpreted as a direction, where -1 is reverse, 1 is forward, and 0 is other.

@see <a href="https://wiki.openstreetmap.org/wiki/Key:oneway">OSM one-way</a>
planetiler-core/src/main/java/com/onthegomap/planetiler/reader/WithTags.java