Anyone can recapture an alley for access to their property. Call Bob Hempler at the City of Houston Public Works and Engineering Department, he handles the miles of red tape and corresponding hoops to jump through. Drainage is the big issue, by code the alley must drain to the ends of the alley, not the neighbors property, so drains may be required (24"!). You can not raise the level of the alley either, if a neighbors back yard currently drains into the alley that condition must exist after you add road base. It is much easier to just talk to your neighbors and work something out without getting the city involved.