^Basically it's to wake up sleepy drivers. The thing is it should be laid in short patches only and before i recall only encountering these on highways.

Yung nakakainis sa suspension is yung mga ukit-ukit sa mga parking ramps (i.e. sa Shang EDSA Plaza) however they do help keep cars from sliding when the ramp is wet.

The dividing lane lines should also serve the same purpose when a car is drifting off course.