but the default Pathparser is currently very hard to read because
we need a complement operator. */
if (s0.getBackEdge() instanceof TransferEdge) return null;
if (s0.getOptions().wheelchairAccessible && !wheelchairAccessible) return null;
StateEditor s1 = s0.edit(this);
s1.incrementTimeInSeconds(time);
s1.incrementWeight(time);
s1.setBackMode(TraverseMode.WALK);
return s1.makeState();
}