Sounds like Cabera erythemaria the Yellow-dusted cream. It matches the region, season, and color you mentioned. The behavior you mention is very very unusual, especially for moths in that particular family (Geometridae). This species is definitely nocturnal and it's very worrying that you were able to see them on open pavement in broad daylight. Not only that, but they were also able to be crushed in such high numbers.

It points to a complete loss of very basic instincts. I've studied what you're talking about before, and there's no good answer on why this happens, but there are a few decent theories:

• Magnetic disturbance We know that there are numerous lepidopteran species which rely on the magnetic field of the Earth to some extent, especially for migration. It is possible that this sensitivity still exists even in moths that don't migrate, just as a vestige. Magnetic disturbances have been known to affect many different animals, even whales and other cetaceans. In this case, the moths could be picking up on some geomagnetic anomaly and its making them suicidal.

• Neurotoxin It is possible there is something in the air or even the nocturnal-blooming flowers that these moths usually pollinate. There are organic compounds, like pyrethroids, don't affect vertebrates because we have sufficient enzymes to break them down. Insects, like moths however have no such enzymes and chemicals like that depolarize and degrade their nervous system, severely affecting movement and reaction. Most pyrethroids become inert in direct sunlight, so either they're, "hiding" inside flowers that only bloom at night or in soil sediments that the moths are getting into.

• Epigenetics This is the least likely scenario out of all of them, and by far the most theoretical. There are some studies on, "inherited memories" in insects, especially butterflies and moths. Epigenetics is the study of how environmental factors change the phenotype of organisms, these changes while not originally caused by heritage are themselves heritable. We know how the migration patterns of lepidopterans are affected by the, "memory" of past migrations. However, the degree to which non-migratory moths like the Yellow-dusted cream are affected is unclear. That could be a part of it, perhaps even the cause itself.

Either way, this behavior is likely a coal-mine canary for ecological damage where you are. I highly recommend you try to find your local wildlife society and give them a call about what you've seen. If it goes on long enough, it could possible begin to interfere with the broader food web of your area, especially for animals which usually eat moths or moth caterpillars.