According to the AASHTO Roadside Design Guide, which is the preferred order for treating roadside obstacles?

The preferred order for treating roadside obstacles according to the AASHTO Roadside Design Guide emphasizes safety and risk minimization for errant vehicles. The correct sequence begins with removing the obstacle whenever possible, as this completely eliminates the potential hazard. If removal is not feasible, relocating the obstacle to a safer distance from the road becomes the next priority, reducing the likelihood of a crash involving that obstacle.

If relocation is also not possible, making the obstacle breakaway is the next appropriate step. This means that the obstacle is designed in such a way that if impacted by a vehicle, it will give way without causing significant harm to the vehicle occupants. The final option, shielding with a longitudinal barrier, is considered if none of the previous methods are viable. This effectively provides a protective buffer between the roadway and the obstacle, further reducing the risk of severe impacts.

This sequence prioritizes the removal and relocation of obstacles first to mitigate risks, before considering modifications like breakaway designs or barriers, which are seen as less effective than eliminating the hazard altogether. This hierarchy is crucial for road safety engineering and aligns with best practices recommended in the guide.