I created an expanded delivery vehicle model building off of the hard work of 
sstratoti and with help from 
mikelud1. The custom model is trained to recognize 
amazon, dhl, fedex, garbage, homedepot, ikea, lowes, target, uhaul, ups, usps, and 
walmart.
Sample captures: 
delivery truck images
Download link: 
delivery.pt (version 
1.0 1.1 1.2 1.3 1.4)
Update: Uploaded a version 1.1 to the same link. I was getting some false positives with 
ups so I added more images and did additional training. Newer model is also smaller and faster.
Update: Uploaded version 
1.2 1.3 with additional training on images for 
usps.
Edit: I'm also working on adding 
uhaul and perhaps 
garbage (truck), though it seems to be prone to false positives on garbage trucks.
Update: Uploaded version 1.4 that now has support for 
uhaul and 
garbage. For now, I would set detection to 90% on garbage to prevent false positives. If anyone would like to donate some images of garbage trucks, I'll add them and retrain the model.