Journal of Traffic Control Device Research

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2025-12-31T14:42:57+00:00

Quantifying How Much Key Factors Influence Freeway Operational Speeds During Noncongested Periods

2025-10-30T21:13:54+00:00

An evaluation of speeds on Texas freeways used data from 243 roadway sensors located in Fort Worth representing operating speeds during daytime and clear weather conditions from 2015 to 2019. The initial evaluation explored how much average operating speeds increased when the posted speed limit (PSL) was raised from 60 to 65 mph, 60 to 70 mph, or 65 to 70 mph. The average operating speed increased between 2.4 to 4.0 mph for 5-mph increase in PSL or 2.9 mph for the 10-mph increase in PSL. The next evaluation identified variables associated with variations in average freeway speeds. The most significant amount of operating speed variation was associated with unidentified localized factors representing 33.8 percent of variability due to differences between detector locations. Yearly shifts in speeds at a given location were found to be the third most relevant source of speed variation (10.6 percent). Geometry was estimated to explain about 7.5 percent, speed limit 4.1 percent, and citations 3.6 percent of the speed variation in this dataset. Geometry, citations, and PSL represent the range of influence for engineering, law enforcement, and traffic management on operating speed. This study estimates that a strategy that entails modifying geometry, changing the PSL, and varying the level of law enforcement presence within the ranges included in this study may impact freeway operational speeds up to 6.2 mph (depending upon existing conditions along with the changes in the geometry, PSL, and enforcement).

Keeping Drivers Right: Iowa’s Low-Cost Strategy to Prevent Wrong-Way Entries

2025-12-15T16:34:30+00:00

Wrong-way driving (WWD) crashes, though infrequent, carry a high risk of fatal and severe outcomes. The Iowa Department of Transportation (Iowa DOT) identified recurring WWD movements at partial cloverleaf (Parclo B) interchanges and implemented a series of low-cost, human-factor-based signing and marking countermeasures. The “gateway treatment” approach emphasized driver guidance through enhanced “Do Not Enter” and “Keep Right” signing and improved pavement markings. Evaluation across multiple sites showed an 88 percent reduction in WWD events per month and no crashes at treated locations since implementation. The results demonstrate that simple, data-driven strategies can deliver substantial safety benefits and serve as a practical model for other agencies addressing WWD risks.

A New Method to Assess Pavement Marking Retroreflectivity for Compliance with the MUTCD Minimum Pavement Marking Retroreflectivity Levels

2025-10-31T15:15:13+00:00

Pavement markings are an important element of the roadway infrastructure providing delineation and safety for human drivers as well as machine visions systems used in automated vehicles, making up larger portions of the vehicle fleet in the US each year. The Federal Highway Administration (FHWA) has published minimum retroreflectivity requirements in the Manual on Uniform Traffic Control Devices (MUTCD). Support documents provided by the FHWA describe methods that can be used to manage pavement marking retroreflectivity. This paper describes the requirements set forth by FHWA and also describes a new tool that agencies can use to manage pavement marking retroreflectivity so that they can be in compliance with the National minimum retroreflectivity requirements.

State of Practice Review: Human Factors Considerations for LED-Enhanced Static Traffic Signs

2025-12-31T15:41:32+00:00

Traffic signs communicate important information that drivers rely on to safely perform driving tasks. Because of their critical role, it’s crucial that drivers are able to detect, recognize, and respond to signs with sufficient time and distance to do so safely. When signs are difficult to detect or not easily distinguishable within a visually complex environment, drivers may miss critical information, which can compromise safe driving performance. As a result, enhancing sign visibility and conspicuity are key components in roadway and traffic control design.

There are a variety of treatments that can be implemented to improve sign conspicuity, including the use of retroreflective materials, the removal of unnecessary or redundant signs, and increases in sign size. In the early 2000s, light-emitting diodes (LEDs) were first introduced within static traffic signs to draw drivers’ attention to particularly important information (Bert, 2021).

From a human factors perspective, the effectiveness of LED-enhanced static signs depends on how drivers perceive, interpret, and respond to these visual stimuli under real-world driving conditions. This report explores literature on the use of LEDs within static signs, examines how their use relates to human factors principles, and describes current guidance and state practices regarding their implementation.

Technology Solutions for Temporary Traffic Control Operations

2025-08-25T16:17:36+00:00

This case study explores the application of Automated Flagger Assistance Devices (AFAD), Portable Traffic Signals (PTS), and Residential Driveway Temporary Signals (RDTS) in enhancing safety and efficiency within temporary traffic control zones. Drawing from agency practices and field evaluations, the study highlights operational benefits, regulatory considerations, and deployment strategies for each technology. The findings underscore the importance of innovative traffic control solutions in reducing flagger exposure and improving driver compliance in two-lane, one-way work zones. These insights support broader adoption and standardization of AFAD, PTS, and RDTS technologies across transportation agencies.

Case Study: Conversion of Solar Rectangular Rapid Flash Beacon (RRFB) to a Solar HAWK or Pedestrian Hybrid Beacon (PHB):

2025-10-31T15:22:16+00:00

The town not only improved the safety at this crosswalk, but also at another school crosswalk in the town on a narrow street with lower speeds by relocating the RRFB equipment (onto new supports) which was more suitable for that particular location and traffic conditions. This project provided a total gain in crosswalk safely townwide. This traffic control change was done more efficiently than typical installations due to utilizing a solar-powered operation as opposed to a traditional utility installation.

The town’s selection of a solar crosswalk traffic control system allows the traffic control devices to be independent of the power grid and associated electrical power boxes, meters, conduits or blackouts which can become a problem during the sever desert summer storms. The children’s safety continues even when the power goes out.

Another saving factor is that there can be less maintenance because modern electronics, batteries and LED technology are becoming highly reliable, and a properly designed system will run by itself for years. There are a few items that need to be checked periodically. You will need to check the batteries every three to five years and check the height of trees around the site for as they grow, they could impair a system's full functioning by casting shade on the solar module(s). Basically, routine tree and sign/signal maintenance is like what the town needs to do with any other traditional traffic sign and signal installation to ensure the (TCD) traffic control device is not blocked by vegetation.

Editor's Welcome

2025-12-31T14:58:24+00:00

The Intricate Interstate

2025-12-31T15:01:43+00:00

The Steady Beacon

2025-12-31T15:05:49+00:00