Commissioners say city, state and rail officials have failed to follow through on improvements first proposed in August 2013.
On Wednesday, city officials submitted a plan to make the necessary safety upgrades by May 29.
"We applaud our municipal partners for coming to the table to provide us with a plan we have been asking for over the past five years,” said Chairman Tom Forese.
The Federal Railroad Administration in 2016 said the crossing had one of the highest incident rates over the last decade. It's among five Arizona sites included on an FRA list of 15 most dangerous crossings nationally.
The 15 crossings had multiple collisions involving trains, automobiles and pedestrians, and the commission says the 35th Avenue crossing had 25 incidents resulting in nine injuries since 2006.
The five Arizona crossings are along Grand Avenue in metro Phoenix.