Alleyways are typically dedicated to the City for acceptance by the original developer who subdivided the lots and recorded the original subdivision plat at the Register of Deeds Office. However, the City may not have officially accepted these offers of dedications. Meaning the alleyways are ingress and egress easements to the City, the public and abutting property owners. Never the less, ownership of these areas only belong to the abutting owners when it is clearly shown on the original property deed or survey.
This does not mean that ownership of these areas belong to the abutting owners. The only time it belongs to the abutting owners is when it is clearly shown on the original property deed or survey. In most cases, it does not and the alleyways are shown on the recorded subdivision plats as being separate from the private parcel property lines.
The only way to permanently close any dedicated right-of-way including an alleyway is through the City right-of-way abandonment process.
Never the less, the only time the ownership of these areas belong to the abutting owners are when it is clearly shown on the original property deed or survey.