Get ready for a campaign that may need lights and sirens.

Lawrence city commissioners unanimously approved a question for the Nov. 4 ballot asking voters to approve a 0.2 percent sales tax to pay for a new police headquarters. Commissioners have left themselves a little less than 90 days to persuade voters to support the nearly $28 million project.

“The work is just beginning,” said City Commissioner Jeremy Farmer. “It will be a fast and furious campaign.”

Commissioners have written the ballot language so that the 0.2 percent sales tax — that equates to 2 cents for every $10 spent — will sunset after nine years. Commissioners also wrote the language so the tax would end sooner than nine years if collections come in greater than projected, which would allow for the project’s bonds to be paid off more quickly.

Commissioners already were in campaign mode Tuesday night, stressing that the tax could not be extended past nine years unless voters approved an extension as part of another citywide election. Commissioners also were working to get voters in the mood to get to the polls.

“This is an extremely important question we’re asking voters,” Mayor Mike Amyx said. “But I believe we have a price range that allows us to feel comfortable asking the voters to approve it. I feel we’ll have a building that will take us generations into the future, and at two-tenths of a percent, I think it is affordable.”

City commissioners last week decided to move forward with the project on a vacant piece of property at 100 McDonald Drive, which is across the street from the Hallmark Cards production plant and along the Kansas Turnpike. Commissioners authorized a $2.25 million contract to purchase the property, contingent upon the sales-tax question winning voter approval.

The total project is expected to cost just under $28 million — about $25.7 million in construction and design costs and $2.25 million for land acquisition. But commissioners are hopeful they will recoup the cost of the land by selling excess city property, including the current West Lawrence police administration building that no longer will be needed once a headquarters facility is built.

The sales-tax question only will ask voters for $24.2 million worth of funding. The city plans to use $1.5 million worth of funding from existing resources that already is built into the city’s 2015 budget.

In other news, commissioners:

• Unanimously approved a 2 percent pay increase for members of the Lawrence Professional Firefighters IAFF Local 1596. The 2015 budget had called for a 1 percent pay increase, but an extra 1 percent was added through negotiations between the city and the union.

• Approved on a 3-2 vote a performance agreement that will provide an 85 percent, 10-year tax rebate to a proposed apartment project and mixed-use retail development across the street from Kansas University’s Memorial Stadium. Commissioners had previously approved most details of the estimated $75 million project that would include 238 upscale apartment units and about 13,000 square feet of commercial space at 1101 and 1115 Indiana Street. Tuesday’s agreement spells out the terms of the incentives package. The agreement does not obligate the developer, Chicago-based HERE LLC, to build the project, but stipulates the city will provide the 85 percent tax rebate if the project is built as it has been proposed. Amyx and Commissioner Bob Schumm voted against the project.