Evaluation of Expanded Uses of Residential Driveway Temporary Signals (RDTS): Turn Lane Volumes and Storage

Traffic management for work zones in rural two-lane two-way highways can be challenging as these segments often intersect with low volume side streets and access points. Residential Driveway Temporary Signal devices (RDTS) (formerly Driveway Assistance Device (DAD)) have provided a solution to improve mobility for traffic entering a one-lane, two-way work zone. These devices have been implemented for several years under experimental evaluations by numerous state and local agencies across the United States. In January 2025, the optional use of RDTS was approved by the Federal Highway Administration (FHWA) under Interim Approval (IA) 23. However, whereas prior experimental use of the DAD allowed the device to be deployed at minor cross-streets and commercial driveways, IA-23 only allows for the RDTS to be used at residential driveways. To that end, this proposed research project will assess the operational effects of RDTS when used at non-residential access points to develop guidance that will inform future policy-making related to the device. The proposed project objectives build upon the work already performed with RDTS/DAD and other temporary work zone signal systems by considering their use at uncontrolled rural low-volume side streets and access points. Of particular interest is the ability of RDTSs to handle traffic on low volume side streets and access points with a focus on turning volumes related specifically to the designed turn lane storage capacity (i.e., the amount of left and right turn storage). The results will include implementation guidance that will delineate appropriate usage cases of the RDTS, including appropriate mainline and access point exiting volumes based on storage capacity of the turn lane(s) departing the access point. Guidance related to future Manual on Uniform Traffic Control Devices (MUTCD) language will also be provided where applicable and appropriate.

Language

• English

Project

• Status: Active
• Funding: $116,292.21
• Contract Numbers:

  TPF-5(545)

• Sponsor Organizations:

  Iowa Department of Transportation

  800 Lincoln Way
  Ames, IA  United States  50010

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Managing Organizations:

  Iowa Department of Transportation

  800 Lincoln Way
  Ames, IA  United States  50010
• Project Managers:

  Clute, Khyle

• Performing Organizations:

  Michigan State University, East Lansing

  Department of Civil & Environmental Engineering
  Institute for Community Development
  East Lansing, MI  United States  48824-1226
• Principal Investigators:

  Gates, Tim

• Start Date: 20251031
• Expected Completion Date: 20271231
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Implementation; Rural highways; Signal devices; Turning lanes; Two lane highways; Work zone traffic control
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01992133
• Record Type: Research project
• Source Agency: Iowa Department of Transportation
• Contract Numbers: TPF-5(545)
• Files: RIP, STATEDOT
• Created Date: Jun 9 2026 12:32PM