Existing Interstate 4 (I-4) from 50th Street (US 41) to the Hillsborough/Polk County Line is a 4 lane divided rural freeway. This facility consists of four 12 foot travel lanes divided by a depressed median with 10 foot (8 foot paved) shoulders on the outside and either 8 or 10 foot (4 foot paved) shoulders in the median. From 50th Street to Hillsborough Avenue (US 92), the existing median is 64 feet wide and from Hillsborough Avenue to the Hillsborough/Polk County Line the existing median is 40 feet wide.. Access to the facility is possible at 12 interchanges with various County and State Highways. The posted speed from 50th Street to Mango Road (CR 579) is 55 mph while it is 65 mph east of Mango Road. The existing right-of-way width is 300 feet between 50th Street (US 41) and Hillsborough A venue and 200 feet between Hillsborough Avenue and the Hillsborough/Polk County Line. The need for the project is based on satisfying existing and projected traffic demands as well as levels of service, safety and geometric deficiencies.

Study Purpose and Need

Existing I-4 accommodates east-west regional travel between the downtown Tampa area and the areas of eastern Hillsborough County, Brandon, Plant City, Lakeland and Polk County. On a statewide level, I-4 accommodates travel between the Tampa/St. Petersburg/Clearwater metropolitan area and the Orlando Metropolitan area, eventually terminating in Daytona Beach.

Having been designed and constructed in the 1950’s and 1960’s, I-4 is inadequate by today’s design standards, particularly in the areas of vertical alignment, clear recovery areas, safety and capacity. This report documents existing characteristics and conditions of the roadway along with the need for an improved facility. The preferred alternative as defined by the approved Master Plan is identified, described and evaluated.

Proposed Improvements

The Department of Transportation is proposing improvements to I-4 from 50th Street to the Hillsborough/Polk County Line. The project length is approximately 23 miles. Segment I from 50th Street to I-75 consists of adding six (6) through lanes and two (2) HOV lanes to the existing four (4) lanes. Segment II from I-75 to Thonotosassa Road (SR 566) consists of adding six (6) through lanes to the existing four (4) lanes. Segment III from Thonotosassa Road to S.R. 39 consists of adding four (4) through lanes to the existing four (4) lanes. Segment IV from S.R. 39 to the Hillsborough/Polk County Line adds 4 through lanes to the existing 4 lanes while maintaining frontage roads. A median barrier wall will also be constructed through the project.

Segment I improvements would replace the existing depressed grass median with a 10 foot wide paved inside shoulder and a 12 foot wide HOV lane in each direction. Segments II, III and IV improvements would replace the existing depressed grass median with a 10 foot wide paved inside shoulder and a 12 foot wide travel lane in each direction.

Segments I and II improvements will also add two (2) 12 foot travel lanes and a 12 foot outside shoulder (10 foot paved) in each direction. Approximately 197 acres of additional right-of-way will be required to construct these improvements.

The existing crossroad structures will be improved to accommodate the improvements to I-4. The proposed improvements would improve I-4’s level of service to acceptable levels.