[doorty]

I thought it would be much bigger and projected onto the glass. Maybe my physics is off, but this form factor doesn't look that impressive.

[hx87]

That might work if the windshield is steeply raked (e.g. Honda Civic) but not if it's closer to vertical.

[diggernet]

"onto an almost completely-clear piece of glass"

I suspect the glass is slightly silvered (similar to fighter plane HUDs), in order to reflect the image better. Wouldn't work nearly as well projecting onto the windshield.