The estimate is based on the cost to keep two police officers in the neighborhood around the clock, according to the Dallas Morning News. But Dallas police backed off that initial estimate on Thursday.
"(We) don't have any idea how much it's going to cost," police spokesman Lt. Andy Harvey said. "We're not quite at that stage quite yet."
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Police said the department and the Secret Service will work out the details in the coming weeks for the former president's security.
"Well, there may be some crowd issues and then, as a result of that, some traffic issues as well," Harvey said.
A spokesman for the city manager's office said the city would consider asking the federal government for reimbursement if the costs become exorbitant.
Dallas police had previously said they would keep 24-hour patrols of Bush's new neighborhood in place based on how much curiosity the public has.
Police do not expect to provide any motorcade security, which will be handled by the Secret Service.