Today's exciting discovery while working on the American Sign Museum book.
The 'nightrider' was a vehicle used by workers at Stalcup Neon in Kansas City, KS, to drive around iinspecting their signs for bulbs that needed replacing. It had a generator installed in the boot to power its own neon lights, but no air conditioning.
I can't say if this photo will be in the final publication, but the book is available for pre-order here: https://48055.blackbaudhosting.com/48055/ASM-25th-Anniversary-Book.