Sounds like you are getting a "designed cover up". There is a part of various laws used to deny what you are seeking which would otherwise be open to public knowledge. I know of no reason why any agency would deny such a request unless it is something they would rather not discuss. When an agency, State or Federal Government is excessively sensitive to a request, they typically hide behind various laws they can quote and wait to see if a person does an appeal, which increases the cost of the review. They of course inform the person inquiring there will be additional fees. Typically, they don't tell you the extent of what the fees may be, although it is usually required.
My guess is that our State prefers to use our money we contribute for road improvements to areas such as "Baltimore" or the surrounding area instead.
However, if you still want to pursue a request for information about the still dangerous interesection, I recommend Senator Jack Bailey. He used to be a police officer and now our Senator. I think he may be of some help. It will probably be a lot easier than what you are encountering.
The intersection remains highly dangerous. A good friend was killed there. And I was nearly killed there. True, it may not be as bad as it once was. But, it still is an intersection to use very strong caution at.