'Forgiving Highway' to enhance highway safety

VEHICLES running off the roads and then colliding with trees or poles, or falling into ditches and ponds causing injury and death, are common incidents on the country's highways. Such accidents may happen as a result of driver's lack of concentration, fatigue, drunk driving, speeding, inconsistent road design, poor driving conditions or faulty vehicle. Since driver error and mechanical fault in vehicles are unpredictable, it is felt that crashes are unavoidable as well. This is why, besides trying to keep vehicles on the roadway, highway engineers also have to try to reduce the number and severity of accidents. Several countries have successfully done so by applying the 'Forgiving Highway' concept.
Forgiving Highway is a concept that is designed to "forgive" mishaps on the road as a result of driver error or faulty vehicle. The objective of this concept is to reduce the severity of the crash in the event a vehicle runs of the roadway.
Providing highway shoulder ensures that even if a vehicle leaves the travel lane, it is still on the paved surface, which will make it easier for vehicles to return to the travel lane. A highway shoulder works as a buffer between the roadway and roadside objects by providing some extra paved space for a stable and clear recovery area for drivers who have left the travel lane.
The second thing is removing and relocating roadside hazards such as trees, poles, boards etc., further away from the edge of the travel way. This greatly reduces the severity of an accident as the vehicles are able to stop without colliding with any object.
In cases where obstacles cannot be removed, they should be 'protected' or be able to 'breakaway' to dissipate the energy of the crash, which helps to reduce the severity of injuries.
Other than fixed objects such as trees or poles, ditches and ponds can also be found along highways. In places where ditches and ponds are located close to the highway, the forgiving highway requires the use of barriers such as guardrails along the highway. To prevent run-off road vehicles from driving through a guardrail, the end of the guardrail is buried or fish (curved) tails are provided to reduce the severity of the collision. In addition, flattening and rounding slopes and ditch sections has also become a standard design as part of the concept.

The writer is a Transportation Engineer working in Thailand.