http://ecomodder.com/forum/showthrea...ics-17717.html Your mirrors are it the problematic flow around the A-pillar. Modern buses and fire engines cantilever them forward. (Or pull them back like on the driver's side in the example) The drivers don't seem to mind.
I'd like to see a hood contour that has a bluff contour like the sleeper cab. But I recognize the value of the sightline. The driver can tell if there is a wheelchair snagged on the front bumper.
Wheelchair user taken on 50-mph ride - US news - Life | NBC News
The brush guards are longitudinal to the air flow, across the flow they would just bend back unless they were backed by an inflated tube or something. Here's an example of a diverter that shows the strength required:
