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Evaluation of Best Practices in Traffic Operations and Safety: Flashing LED Stop Signs


This study examines the implementation and efficacy of flashing LED stop signs as a traffic control and safety measure within Virginia. Initially, a comprehensive review of overseas literature highlighted 42 traffic operations and safety technologies previously unutilized within the state. From this review, 12 technologies were identified as promising candidates for pilot testing. Among these, the flashing LED stop sign was selected for an in-depth evaluation due to its potential to enhance road safety at intersections with historically higher crash rates than expected.

The investigation focused on a flashing LED stop sign installed at a T-intersection in western Albemarle County, identified for its above-average number of incidents. The effectiveness of the LED stop sign was primarily assessed based on two criteria: the average speed of drivers approaching the sign and the compliance with the stop command. Results demonstrated a statistically significant reduction in vehicle approach speeds by 1 to 3 mph post-installation, with the most notable reductions occurring during nighttime. This suggests that the flashing LED stop sign effectively enhances driver awareness and potentially contributes to safety improvements at critical intersections. However, the study found the outcomes of the compliance evaluation to be inconclusive, indicating a need for further research in this area.

In light of the observed benefits, particularly in speed reduction, the study advocates for the consideration of flashing LED stop signs as viable safety countermeasures at intersections where crash rates exceed averages or excessive speeding is prevalent. A preliminary cost-benefit analysis supported the deployment of such measures, indicating that the reduction in crash occurrences justifies the installation costs, provided that at least one crash is averted.


The imperative to enhance highway safety continues to command the attention of a broad spectrum of stakeholders, including federal, state, and local government officials, as well as public and private organizations. This sustained focus is driven by the recognition that, despite substantial advancements in vehicle and highway safety technologies — which, according to a U.S. Department of Transportation study, have saved approximately 329,000 lives since 1960 — a significant number of fatalities still occur on the nation's roads each year. Specifically, in Virginia, despite having the 12th safest highway system in the nation and a decreasing fatality rate over time, there were 961 recorded deaths on the state's highways in 2006. In an effort to address this ongoing loss of life, the American Association of State Highway and Transportation Officials (AASHTO) has set forth a national highway safety goal aimed at reducing fatalities by 1,000 each year, with the ultimate objective of saving over 50,000 lives within a decade and halving the number of fatalities over the next twenty years.

Virginia, aligning with this national emphasis on improving highway safety, has developed its own Strategic Highway Safety Plan for 2006-2010. The plan aims to reduce the number of deaths and injuries reported in 2005 by 100 and 4,000, respectively, by the end of 2010. It adopts a multi-faceted approach, seeking to identify issues related to human factors, the environment, and infrastructure, with proposed countermeasures rooted in current research, collaboration with safety partners, and empirical evidence.

In the context of evaluating new safety technologies and practices, Virginia has looked beyond its borders, recognizing that while the United States is a leader in traffic operations and safety, there are valuable technologies and practices used internationally that are not yet widespread in the U.S. An earlier research initiative identified 42 such technologies and practices not currently in use in Virginia, assessing them against ten subjective criteria to determine their suitability for pilot testing in the state. This evaluation process categorized two measures as ready for immediate implementation without pilot testing, twelve as promising candidates for pilots, twenty-two as questionable for piloting, and six as unsuitable for pilot studies. Among the twelve measures deemed promising were colored and textured pavements for speed warnings, animated eyes on warning signs to alert drivers to pedestrian crossings, and stop signs enhanced with flashing light-emitting diodes (LEDs) at each corner, the latter of which is the focus of this report.

This introduction sets the stage for a detailed examination of the pilot testing of flashing LED stop signs in Virginia. It highlights the collaborative efforts of Virginia Department of Transportation’s (VDOT) central office and district traffic engineers who, informed by the aforementioned research, selected the flashing LED stop sign for pilot testing based on its potential to contribute significantly to highway safety. This selection process underscores Virginia’s commitment to leveraging innovative technologies and practices to reduce roadway fatalities and injuries, reflecting a broader national and state-level initiative to improve highway safety through evidence-based strategies.

Purpose and Scope

Purpose of the Study

The primary goal of this research was to conduct a comprehensive evaluation of the impact of flashing LED stop signs on driver behavior and traffic safety. This involved before-and-after studies to assess changes in vehicle speeds and compliance with stop signs after the installation of flashing LED technology. Unlike traditional traffic safety studies, this effort did not include crash analysis due to the unavailability of the recommended minimum of three years of post-installation crash data.

Scope of the Study

The study was limited to the examination of flashing LED stop signs installed at one specific location in Virginia. The effectiveness of these signs was measured based on two primary criteria: the average speed of vehicles approaching the stop sign and the rate of compliance with the stop sign.


Selection of Pilot Site and Background Information Collection

A critical site for the study was identified on Virginia Primary Route 151 at its T-intersection with U.S. Route 250 in Albemarle County, selected by VDOT’s Lynchburg District traffic engineers. This location was chosen due to its higher-than-average crash rate and specific challenges such as high approach speeds, limited sight distance, and sign clutter. Various existing countermeasures at the site were documented, including oversized stop signs and rumble strips, to understand the baseline conditions before the introduction of the flashing LED stop sign.

Development of Evaluation Plan

The study's evaluation plan aimed to assess the flashing LED stop sign's effectiveness in increasing driver awareness and compliance. This involved detailed planning for the collection of traffic volumes and speeds, both before and after the sign's installation, across various time periods and conditions to gauge immediate and longer-term effects.

Installation Process

The installation involved setting up a 48-inch flashing LED stop sign equipped with solar-powered LEDs. Specific details about the sign's features, including its solar panel, battery pack, and prismatic sheeting, were noted, alongside the cost and logistical considerations of the installation process.

Data Collection and Evaluation

Data were collected at multiple points along Route 151, with traffic counters placed at specified distances from the intersection to capture vehicle speeds before and after the sign's installation. Additionally, a stop sign compliance study was conducted to observe and record driver behavior in relation to the stop sign under various conditions.

This structured approach to the research methodology ensures a comprehensive evaluation of the flashing LED stop sign's impact on traffic safety and driver behavior, contributing valuable insights to the field of traffic management and safety engineering.



Evaluation of Flashing LED Stop Sign Effectiveness

The implementation of the flashing LED stop sign yielded a measurable, albeit modest, reduction in vehicle speeds. This outcome, while statistically significant, prompts a deeper consideration of the practical implications for traffic safety improvements. The observed speed reductions were relatively minor, suggesting that the influence of the flashing LED stop sign, while positive, may be limited in contexts where other safety measures are already in effect.

Contextual Impact of Pre-existing Measures

The environment surrounding the chosen intersection on Route 151 was already equipped with multiple safety measures designed to alert drivers to the impending stop requirement. These measures likely established a baseline reduction in speed, which could have attenuated the incremental impact of the flashing LED stop sign. This pre-existing safety framework underscores the need to evaluate new interventions within the context of the overall safety ecosystem at a given site.

Compliance with the Stop Sign

Regarding the stop sign compliance aspect of this study, the inconclusive results point to the complex interplay of factors influencing driver behavior at stop-controlled intersections. While other research has highlighted the potential of flashing LED stop signs to enhance compliance significantly, the specific conditions at the studied intersection—already bolstered by various visibility and awareness-enhancing measures—may have diluted the unique contribution of the flashing LED technology.



The study provides important insights into the effectiveness of flashing LED stop signs as a traffic safety measure:

  • Effectiveness in Speed Reduction

  • Flashing LED stop signs have been proven to effectively reduce vehicle speeds as they approach an intersection, particularly in conditions where sign visibility is compromised. While the reduction in speed may be modest, typically ranging from 1 to 3 mph, the significance of this decrease should not be understated, especially during dusk and nighttime hours when visibility issues are exacerbated.


FAQ: How can TraffiCalm Help with Your Flashing LED Stop Sign Solutions?

Q: How does TraffiCalm's flashing LED stop sign address visibility issues at intersections?

A: TraffiCalm's flashing LED stop signs are designed to enhance the visibility of stop signs, especially in areas where traditional signs may not be as noticeable due to environmental factors or high-speed areas. As noted in the study, these signs have proven effective in reducing vehicle speeds by making the stop sign more visible, particularly during dusk, nighttime, or other low-light conditions.


Q: Are TraffiCalm's flashing LED stop signs compliant with MUTCD and recommended by DOTs?

A: Yes, TraffiCalm's flashing LED stop signs are fully compliant with the Manual on Uniform Traffic Control Devices (MUTCD) standards. Their design and functionality meet the strict guidelines set forth by the MUTCD, making them a trusted choice recommended by Departments of Transportation (DOTs) across the country for improving intersection safety.


Q: What makes TraffiCalm's flashing LED stop signs effective in areas with high crash rates?

A: The effectiveness of TraffiCalm's flashing LED stop signs in areas with high crash rates lies in their ability to attract drivers' attention well in advance of the stop sign. The study highlighted significant speed reductions and potential improvements in compliance at intersections equipped with these signs. By enhancing sign visibility, TraffiCalm's signs contribute to giving drivers more reaction time to stop safely.


Q: Can TraffiCalm's flashing LED stop signs be integrated into existing traffic safety strategies?

A: Absolutely. TraffiCalm's flashing LED stop signs are versatile and can be seamlessly integrated into existing traffic safety strategies. They serve as an additional layer of safety at intersections, complementing other measures such as "stop ahead" signs, pavement markings, and rumble strips. Their integration into a comprehensive traffic management plan can address specific safety challenges of an intersection, as demonstrated in the study.


Q: How does TraffiCalm ensure the long-term effectiveness of its flashing LED stop signs?

A: TraffiCalm is committed to the long-term effectiveness of its flashing LED stop signs through continuous innovation, rigorous testing, and feedback incorporation from DOTs and traffic safety professionals. The company provides durable, high-quality signs designed for longevity and minimal maintenance, ensuring that they remain an effective safety measure over time.


Q: What support does TraffiCalm offer for communities looking to improve intersection safety?

A: TraffiCalm offers comprehensive support for communities aiming to enhance intersection safety, including site assessment, product selection guidance, and installation support. The company works closely with traffic engineers, safety officials, and community leaders to identify the most appropriate solutions for their specific traffic safety challenges, informed by studies like the one discussed and best practices from across the country.


Q: How can interested parties learn more about implementing TraffiCalm's flashing LED stop signs in their area?

A: For more information on implementing TraffiCalm's flashing LED stop signs, interested parties can contact TraffiCalm directly through their website or by reaching out to your Regional Sales Manager. TraffiCalm also offers informational resources, case studies, and consultation services to help communities make informed decisions about enhancing their traffic safety measures.



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