You can build OpenALPR with CUDA support following the example in this script
Don't forget to create 2 copies of the alpr config file. One for CPU and one for GPU.
If the git repo for openalpr is at /opt/openalpr
this would be the commands to create the config files:
cp /opt/openalpr/config/openalpr.conf.defaults /etc/openalpr/openalpr.conf \
&& cp /tmp/etc/openalpr/openalpr.conf /etc/openalpr/openalpr.conf.gpu \
&& sed -i 's/detector =.*/detector = lbpgpu/g' /etc/openalpr/openalpr.conf.gpu