What's meanings of outputs in detectnet_v2?

Firstly , please check your postprocessing is correct.

For postprocessing of Traffic Cam Net(Based on detectnet_v2, please refer to /opt/nvidia/deepstream/deepstream/sources/libs/nvdsinfer_customparser/nvdsinfer_custombboxparser.cpp

More reference: Run PeopleNet with tensorrt - #3 by steventel

For the difference of model output, please refer to

In TLT the preprocessing of SSD image is like below:

assume RGB input values which range from 0.0 to 255.0 as float
change from RGB to BGR
then subtract channels of input values by 103.939;116.779;123.68 separately for BGR channels.