This information was provided by Chicago Title:
Streets as constructed vs. streets as dedicated:
A common issue in many older neighborhoods is the width of the street as dedicated on the recorded plat, versus the width of the constructed street on the ground.
In many cases, the street as dedicated is wider than the street as constructed. This leads to a portion (sometimes a large portion) of what looks like the front yard and the property of the owner, actually being within the street. In some cases, actual improvements such as the garage, driveway, landscaping and perhaps even the dwelling itself may encroach into the street.
If an inspection is performed by the title company, and such an encroachment is discovered it will be disclosed by the company. However, the buyer may want to take this little anomaly into consideration when considering making an offer on a particular property. The same issue may also exist when properties abut active or abandoned railroad right of ways.