• What are the planned improvements?
  
  This project will improve the driving environment for the large number of motorists who use I-10 by eliminating an S-curve from the alignment. Also, portions of I-10 and State Route 90, including the overpass, underpass and ramps that comprise the interchange, will be widened to provide greater capacity for future needs.


• Why is it important to realign Interstate 10 west of the junction with State Route 90 as part of this project?
  
  By eliminating the S-curves, that stretch of Interstate 10 will be brought into better compliance with contemporary design standards and will reduce the potential for motorists accidentally running off the highway. Also, this project will increase the amount of banking on two other nearby curves to improve driving conditions.


• Why is the interchange being replaced now?
  
  ADOT's mission is to provide a safe, efficient and reliable regional transportation system. One of the ways we accomplish that is by updating our highways to meet current and future needs. It has become apparent, given increases in population and highway use; including commercial truck traffic; that the time is right to improve this traffic interchange and the highways that serve it. We anticipate an even larger volume of traffic using this interchange over the coming decades as our population continues to grow. The improvements that will be made during this project will allow us to accommodate the increased use and will provide the capability to add lanes to meet future needs.


• Why is State Route 90 being lowered beneath Interstate 10?
  
  The new I-10 bridge decks will be thicker than the existing decks and, in order to provide 16-feet, six-inches of clearance for trucks passing beneath on SR 90, we need to lower the elevation of that highway. This also will allow us to avoid having a sudden rise on the overpass, which creates a roller coaster effect for traffic passing over on I-10.


• How does this project relate to ADOT's other major project in this area the new Marsh Station Road traffic interchange?
  
  The Marsh Station Road project, which is 13 miles west of State Route 90, is being constructed to allow oversized loads to remain on Interstate 10. Right now, over-height vehicles are forced to exit I-10 and take a lengthy detour on several state routes to avoid the existing interchange at Marsh Station Road and the adjacent railroad bridge. When the new Marsh Station Road interchange is complete and when Union Pacific Railroad replaces its existing bridge, I-10 will accommodate over-height vehicles across Arizona with improvements at these important junctions.


• When was the existing traffic interchange at I-10 and SR 90 constructed?
  
  The plans are dated 1961 so construction took place shortly after.