In the Classic editor, 8-4-1 and 8-4-2 don't have hitbox for the guardrails , so you can go through them. I already saw this on Day 1 version of the game, surprised that this is not fixed yet.
http://i.imgur.com/DZSxOQc.png
http://i.imgur.com/PFXhMgt.jpg
http://i.imgur.com/xZ6dbVD.jpg
You can clearly see that the car goes through the barriers. Don't think any other asphalt road blocks have this problem only with these two Y shaped ones.
