Panasonic WV-S1531LTN

I am testing Panasonic camera WV-S1531LTN with OpenALPR on road where vehicles moves between 40-140km/h.
I am using JPEG stream from camera with 1280x720, 15fps, fine quality image.
I am getting good result.
My question is , if camera can deliver 30fps JPEG stream to this software, the reading performance can be better for fast moving vehicles ? Will it affect the processing performance of the software ?
Can I use H.264 stream of the camera ? reading performance would be same as JPEG stream or lower ?

We have been working with ALPR under similar conditions for many years, and in my experience I would say that the overall performance of the entire system depends very little on the fps of the camera. Of course you need to be able to capture the vehicles as they move across the field of view, but adding more images of similar quality only marginally increases the reading performance. The factors that really change the performance dramatically is the dynamic range of the camera (the ability to read plates hit by direct sunlight vs. in the middle of the night), and being able to cap the shutter speed at the higher end (using too long exposures will blur images of rapidly moving objects).
I presume a H.264 stream uses higher resolution images than JPEG? If you can resolve the number plates clearly in the image, this should not be a factor either. Using larger resolution images is only going to slow the processing down. As long as the plate is on the order of 100 pixels wide (or wider), adding more pixels generally does not significantly increase the reading performance.