- If there is no median, use a 2-way segment
- If there is a median wider than 12 meters, use a divided roadway
- If there is a median less than 12 meters wide, but there is a special lane between the two directions (bicycle lane, emergency vehicle lane, or there are cross streets or u-turns every 300m or closer, then also use a divided roadway
- otherwise, use a 2-way segment