New traffic control device approved for residential driveways
By: Tiffany Kautz, Traffic Standards Engineer, Office of Traffic Engineering
The FHWA has issued an interim approval for the Residential Driveway Temporary Signal (RDTS), with Minnesota receiving a Statewide Interim Approval. The RDTS is designed to improve safety and efficiency on two-lane, two-way roads by controlling traffic entering from residential driveways during construction or maintenance activities that result in the closure of one lane. The use of the RDTS is optional.
The RDTS may be used to replace flaggers at residential driveways within one-lane, one-direction temporary traffic control zones. It features a three-section signal face with a circular red indication and two yellow arrows, along with signing to guide motorists.
Background and research
The RDTS addresses challenges during construction or maintenance on two-lane roads, where one lane is closed, leading to alternating one-direction traffic. Traditional methods using flaggers or temporary signals were less effective, especially at residential driveways.
Over a ten-year period, from 2013 to 2023, 10 state departments of transportation (DOTs) including Indiana, Kansas, Massachusetts, Michigan, Mississippi, Nebraska, New York, Ohio, Texas, and Virginia, experimented with the RDTS. They evaluated its operational and safety effectiveness, cost efficiency, and optimal design.
Findings and benefits
The FHWA's evaluation of the RDTS experiments showed positive results:
- Safety: High compliance rates and no crashes were reported. The RDTS reduced flagger exposure to traffic, especially in low-light conditions.
- Operational improvements: Significant improvements in traffic flow were noted. For instance, the Indiana DOT reported a 15-20 percent increase in green time during peak hours, while the Ohio DOT observed shorter delays and queue lengths.
- Cost efficiency: The RDTS proved to be cost-effective compared to using flaggers, with significant savings reported by DOTs in Kansas, Massachusetts, New York, and Ohio.
- Design optimization: The most effective signal face layout was found to be an inverted “T” configuration using flashing yellow arrows. The inclusion of a “No Turn on Red” sign and regulatory TURN ONLY IN DIRECTION OF ARROW plaque were recommended.
Conditions of use
The RDTS is limited to use at residential driveways within the one-lane, one-direction portion of temporary traffic control zones on two-lane, two-way roads. The device is required to meet the following criteria.
- A three-section inverted “T” signal face is used, consisting of:
- A circular red on top.
- Two bimodal yellow arrows below.
- A NO TURN ON RED (R10-11b) sign with a TURN ONLY IN DIRECTION OF ARROW plaque is displayed.
- Additional criteria include:
- Only one signal face is installed per driveway.
- A steady yellow change interval follows the flashing yellow arrow.
- The device operates in coordination with the main Temporary Traffic Control Signal.
- The signal flashes red when the main signal is in flashing mode.
- When not in use, the signal is either covered or turned away from view.
Please see the Interim Approval for the Optional Use of Residential Driveway Temporary Signal (IA-23) Memorandum for more details.
Minnesota, through MnDOT, has received a Statewide Interim Approval for the RDTS. Jurisdictions within the State of Minnesota using the RDTS must adhere to the following requirements:
- Abide by the specific conditions for use of the RDTS as contained in the Interim Approval for the Optional Use of Residential Driveway Temporary Signal (IA-23) Memorandum;
- Provide MnDOT with a list of locations where devices have been installed, which can be done by completing the Interim Approval Reporting form; and,
- If needed,
- Restore the site(s) of the interim approval to a condition that complies with the provisions of the Minnesota Manual on Uniform Traffic Control Devices (MN MUTCD) within 3 months following the issuance of a Final Rule on the traffic control device; and,
- Terminate use of the device or application installed under the interim approval at any time that it is determined that significant safety concerns are directly or indirectly attributable to the device or application. The FHWA's Office of Transportation Operations has the right to terminate the interim approval at any time if there is an indication of safety concerns.
Questions
For questions, please contact Tiffany Kautz at tiffany.kautz@state.mn.us or 651-234-7388, or Michelle Moser at michelle.moser@state.mn.us or 651-358-9094.