Polk County is included in the Central Florida Regional Planning Model (CFRPM) area, despite the fact that it is not located within the Florida Department of Transportation (FDOT) District 5 management area. It has a unique presence within CFRPM. This article will explain how it is incorporated into CFRPM, and the differences between its place in CFRPM and the District One Regional Model (D1RPM).
Why is Polk County Included in CFRPM
Polk County was added to CFRPM starting in version 5.0; only a portion of the county was included. The entire county was added in version 6.1.
The unique geographic location of Polk County, despite it being located in a different FDOT managing district, necessitate its inclusion in CFRPM. Polk County lies between the two large metropolitan regions of Central Florida: Orlando and Tampa. The eastern portion of Polk County has many ties to the Orlando region; similarly, the western portion has ties to Tampa.
The most important tie, in terms of travel demand modeling, is transportation and trip-making related. Eastern Polk County contains many residents that work, shop, and make significant other trips to Osceola and Orange counties. This is especially true in the Four Corners region (the confluence of Orange, Osceola, Lake and Polk counties), as well as Haines City, Davenport, and Poinciana. Low housing costs and close proximity to facilities such as I-4 and SR 429 have caused this area to grow drastically within the past 20 years. Many of the residents work in the theme park attraction area, and there are also numerous vacation rentals that cater to theme park visitors. There are also many existing shared transportation facilities: I-4, US 17/92, US 27, and US 192, with others planned.
The United States Office of Management and Budget also includes Polk County as part of the Orlando-Lakeland-Deltona Combined Statistical Area (CSA).
Differences between Polk County in CFRPM vs D1RPM
Aside from the traditional differences between travel demand models, a few differences are important to note.
- The D1RPM only contains scenarios for the Base Year and Horizon Year; CFRPM contains scenarios for every five-year period between the two (i.e. 2020, 2025, etc.)
- CFRPM only contains Cost Feasible projects from the Polk Transportation Planning Organization's Long Range Transportation Plan (LRTP). Illustrative, partially-funded, and developer-sponsored projects are not included; they may be included in the D1RPM.
- In northeastern Polk County, there are additional roadways included in the CFRPM network than the D1RPM network.
- Posted speed limits are an input in the CFRPM network; D1RPM uses a lookup table based on Facility Type and Area Type.
- Zones & ZDATA
- CFRPM largely borrows the same Transportation Analysis Zones (TAZ) from the D1RPM. However in northeastern Polk County, CFRPM has additional TAZs, split from ones provided by the D1RPM. This is due to the need for enhanced model fidelity in this region. There is a many-to-one boundary match between these TAZs in both models; meaning, many zones in CFRPM will fit perfectly into a single zone in the D1RPM, with no overlapping or excluded areas. The CFRPM TAZ feature class has a field containing TAZ number equivalencies in the D1RPM.
Which Model to Use
With Polk County being included in two different travel demand models in Florida, the question often arises as to which one should be used when modeling transportation projects in Polk County.
The answer to that is: on a project-by-project basis; and depending the location of the project.
An unofficial delineation boundary, consisting of US 27 and County Road 580, has been discussed between FDOT District 1 and District 5.
- If the project is located in Lakeland, Bartow, or generally west of US 27 and south of CR 580, the D1RPM should be used.
- If the project is located east of US 27 and north of CR 580, it is recommended that CFRPM be used.
- Before executing a modeling project in this area, it is required to get concurrence with staff at both FDOT District 1 and District 5, as a courtesy to both. These conversations should include the modeling staff, project manager(s), as well as consultant staff.
- Even if the project is located in this area, do not make an automatic assertation that CFRPM will be used. There are other factors that may play into the decision to use either model.
- This does NOT make a statement, implicit or otherwise, that one model is better than the other.