Road Sign

Thoughts on setting license plates in mixed/lowercase?

Given that research on road sign legibility supports the use of mixed case over uppercase, would it be worth examining the case of license number plates as well?
I'm really bad at remembering car plates, and I think it's partly attributable to the block shape issue. So I wondered whether they might be easier to read and remember if, at the least, the letters were set in lowercase (probably large x-height).

Does anyone have any thoughts on this? Is it worth investigating, or is it a non-issue?

By the way, I'm nowhere near as well-versed in type research, theory, and practice as many of you are, so please be gentle if I seem uninformed.