I took the photo below in Cebu during one visit in 2010. The signs were posted along the coastal highway in the South Road Properties (SRP). Our friend explained that the signs were supposed to have been posted there as a spiteful message by a former mayor of the city to a political rival whose entourage commonly used the highway going to the city. Apparently, the vehicles on the politician’s convoy have the habit of using their lights even during the day to announce their presence in traffic. It seems their headlights are always on high beam (i.e., bright), which can be distracting for opposing traffic even if there is a median island along the highway. I can also imagine that in the past, vehicles on the convoy would probably use sirens or wangwang.
Many Philippine roads, especially in the rural areas, do not have lighting or are poorly lit, and it would be a lucky night when the moonlight is sufficient to provide illumination. Thus, it is understandable if we use the high beam or bright mode of our headlights when we are driving along dark roads and if there are no traffic on the opposing lanes. However, I think it is a matter of road courtesy that we dim lights when we encounter other vehicles on the road at night. Maybe it’s okay if the opposing lanes are divided by a median (like the island with plants in the photo) or barrier such that the lights are dissipated somehow. But most Philippine highways are undivided and thus, bright lights may become a hazard for motorists and lead to road crashes. If only for this, then there is actually a sound basis for reminding drivers to dim their headlights, especially in the city where there is significant vehicular traffic.