The HPS looks just as glary. LEDs should thrive in highmast installations. The narrow, concentrated beam is perfect for the high mounting height. The light won't spill for acres and acres like HID highmasts would.
Yes and no I say. LED's may no spill light as much as HPS, but I find if I lock on to one at night it is a dangerous effect to my driving vision! I would like to see the visors I've seen on the HPS used on LED highmasts, but never have. I guess the understanding of visors are to limit light trespass, but they will definitely reduce glare for drivers under mega LED's! Some LED models I've seen (even city streetlights) are much glare-ier but do not light the road more than competitors. In all honesty I'm noticing the waffle panel variety to be less intense if your eye catches it vs the couple diode blasters.