If you have “cuda-8.0” under /usr/local, it’s likely Cuda was installed but the path is missing from .bashrc. You can take look at “cuda-l4t.sh” to see how the path to CUda is added.
You can decide if you want to use “cuda-l4t.sh”, or use command in “cuda-l4t.sh”, e.g., to fix the missing path.
I did not use Jetpack to install Cuda, I did manual installation using “cuda-l4t.sh” and built Cuda samples natively on TX1.