I don't think anyone will be able to get the number plate from that size image. If you had the original 8 megapixel image (or whatever your camera can do) it might be easier.
I'm also not sure if this is an allowed use of the forum! Either way, you do know the intersection, and the exact time, it could be worth seeing if the police can find any security cameras in the area.
I'm also not sure if this is an allowed use of the forum!
No problem with that, we've had lots before. And they all boil down to the same: not enough pixels.
This "zoom and enhance" trick only works on TV, not in the real world.