I've been invited to give feedback to all Parsons students, regarding your thesis projects.
Your project idea really stands out because it is super specific. I had not considered the "unintended consequence" of silent hybrid cars in this context before. So, in this regard, good for you for identifying a niche issue and solving for it.
I'm unclear on how the alert will be projected from the car's electronics / engine...and whether or not branding a sound makes sense. Perhaps a universal sound could be applied to all hybrid/silent automobiles around the world - and the manufacturers could form a community with respect to this issue. (Rather than it be solely a Toyota-branded initiative.) An analogy that comes to mind is the beep-beep alert on trucks that kicks in when they shift into reverse driving mode...
Overall, I like the project and I think it has legs. Most importantly, it raises awareness about a sector of society that often is overlooked in public space. Congratulations and good luck, J.