I learned the hard way you will get best results with a custom model trained on images from your cameras. Granted most of us do not have many to start with so it is a good idea to add an action to your alerts to save a copy (preferably without markup) to a folder or better yet folders named for the first object found.
If you need a starter set for things you might see in the Texas hill country you can check out my dataset and model on avatar42 | Datasets Novice I'm planning on about doubling the number of images and moving them into folders by main object soon. Also separating day and night images into separate object classes.
I also have some utils to help making your own custom models easier at GitHub - avatar42/deepstack: DeepStack utils.
I tried your model out last night and found it really nice. I like how you broke "truck" down into types and made trucks, pick-ups, garbage, vans, etc. I just looked through the recordings today and your model works wonderfully. It was not slow, yet seems accurate so far. (as for cars, trucks, people,etc) I have not had any critters go by the cameras it is installed on yet. I am going to have to take a shot at making my own now.