Executive Summary
The Florida Department of Transportation (FDOT) District Seven, in collaboration with the City of St. Petersburg, is preparing an Interchange Operational Analysis Report (IOAR) to document the traffic operational and highway safety benefits of improving the southbound Interstate 275 (I-275) (State Road (SR) 93) off ramp at 22nd Avenue South in Pinellas County, Florida. The proposed improvement is needed to alleviate existing traffic operational/highway safety deficiencies on the southbound I-275 off ramp and on westbound 22nd Avenue South between I-275 and US 19.
Existing traffic conditions at the southbound I-275/22nd Avenue South ramp terminal intersection were evaluated to establish a baseline condition for comparison of operations with and without a series of improvement alternatives. The results of the existing conditions analysis indicates that the
southbound-to-westbound right-turn movement on the southbound I-275 off ramp at 22nd Avenue South operates at an unacceptable Level of Service (LOS) E or worse during both the AM and PM peak periods. The vehicle queue lengths that occur on the southbound approach are over 1000 feet
long, which causes traffic to back onto the I-275 mainline gore area. In addition to performing level of service and vehicle queue length analyses, a safety evaluation of the study corridor revealed that there were 128 crashes within the three-year period from 2011 to 2013, of which, 60 occurred on the southbound I-275 off ramp.
Five improvement alternatives were analyzed using the Highway Capacity Manual (HCM) 2010 Module of Synchro for the southbound I-275 off ramp/22nd Avenue South intersection. An evaluation of both the safety and operational aspect of each alternative was performed to identify a
recommended improvement alternative. The recommended Build Alternative is to provide dual, signalized right-turn lanes on the southbound I-275 off ramp. This alternative significantly reduces the control delay of the southbound I-275 off ramp approach and provides an acceptable LOS C
during both the AM and PM peak periods. Queue lengths are also reduced to ensure there is no queue spillback that could affect mainline operations on southbound I-275. This improvement can be accomplished for approximately $544,000, and no right-of-way or environmental impacts are
expected.
Purpose and Need
Download the Purpose and Need (PDF, 21KB)
I-275 is a vital link in the local and regional transportation network and serves as a critical evacuation route. As a major north-south corridor through Pinellas County, I-275 links the Tampa Bay region with the remainder of the state and the nation supporting commerce, trade, and tourism. I-275 is part of the Strategic Intermodal System (SIS), a statewide transportation network of highways, railways, waterways, and transportation hubs that provides for the movement of goods and people at high speeds and high traffic volumes. As an SIS facility and part of the regional roadway network, I-275 is included in the 2035 Regional Long Range Transportation Plan (LRTP) developed by the West Central Florida Metropolitan Planning Organization’s (MPO) Chairs Coordinating Committee (CCC) and the Tampa Bay Area Regional Transportation Authority (TBARTA) Master Plan.
Preserving the operational integrity and regional functionality of I-275 is critical to mobility and economy of the Tampa Bay region. Twenty second Avenue South is an important east-west arterial roadway in southern Pinellas County that links the City of Gulfport to I-275. Twenty second Avenue South intersects 34th Street South (better known as US 19) west of I-275. Traffic volumes are projected to increase in the future along 22nd Avenue South and its major cross streets, as well as on I-275. The increased traffic traveling along the 22nd Avenue South corridor, combined with increased traffic entering and exiting I-275, will cause increased delays and congestion.
Travel Time Savings
| Network-wide Comparison |
Design Year 2045 No-Build Alternative |
Design Year 2045 Build Alternative |
Difference |
| Total Travel Time (hrs) |
AM Peak |
77 |
30 |
-61% |
| PM Peak |
120 |
36 |
-70% |
FDOT Emergency Travel Alert: For information on the current situation, please visit the following
page - 
