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An overview of the updated Signal Warrants module

Renan Favero2024-11-04T18:49:22+00:00October 31, 2024|
Renan Favero
Renan Favero

Before installing a traffic control signal, a thorough study of traffic operations, pedestrian activity, physical road characteristics, and safety conditions is necessary, and mandated by many public agencies. The updated Warrants module in HCS 2025 automates the evaluation of these factors, providing a comprehensive check against all traffic signal warrants to determine if a signal is justified at a particular intersection.

The new HCS 2025 includes the latest Warrants updates from the Manual on Uniform Traffic Control Devices (MUTCD) 11th Edition, published in 2023. This article will provide an overview of the 9 warrants included in HCS 2025 to evaluate the need for traffic signal control, highlighting the major updates:

Warrant 1: Eight-Hour Vehicular Volume

This warrant is intended for intersections where traffic flow is the primary reason for installing traffic signal control. It considers 8 hours of traffic volume from both the minor and major approaches to the intersection.

Warrant 2: Four-Hour Vehicular Volume

Applied where intersecting traffic volumes are the principal reason for signal installation. This warrant uses specific criteria, especially on high-speed roads or in small communities, where the buildup of traffic occurs over a shorter period.

Warrant 3: Peak Hour

This warrant is applied in situations where the minor-street traffic experiences undue delays during peak hours. It evaluates whether 1-hour of traffic volume exceeds certain thresholds.

Warrant 4: Pedestrian Volume

This warrant applies when the traffic volume on a major street is so heavy that pedestrians experience significant delays in crossing. It evaluates both vehicular traffic and pedestrian crossings on the major street.

WHAT IS NEW

The updated Warrants HCS 2025 now allows traffic criteria for this warrant to be applied separately to each direction of vehicular traffic when the street is divided by a median that provides a pedestrian refuge.

Users can select the specific approaches with pedestrian medians (see figure below), and the software will adjust the analysis accordingly. If both approaches of a major street have a median, the method evaluates directional traffic volumes. In cases where only one approach has a median, or none at all, the method considers the total bidirectional traffic flow on the major road. Additionally, a new checkbox allows the analysis of crossing locations where the 15th percentile of pedestrian speeds is below the threshold of 3.5 ft/s.

Warrant 4 Pedestrians - New inputs

Warrant 5: School Crossing

This warrant applies when schoolchildren crossing a major street is the primary reason for considering the installation of a traffic control signal. It evaluates the number of schoolchildren and the available gaps in traffic during the highest crossing hour.

Warrant 6: Coordinated Signal System

It is applied when it is intended to ensure that signals are coordinated to improve traffic flow and reduce stops along a corridor.

Warrant 7: Crash Experience

This warrant applies when the frequency and severity of crashes are the primary reasons for installing a traffic control signal.

WHAT IS NEW

The updated Warrants HCS 2025 includes important updates to crash thresholds. While the previous warrants version, based on MUTCD 2009, requires a yearly crash frequency over a 12-month period along with a traffic flow threshold, the updated version maintains the traffic flow threshold but introduces new criteria for crash frequency. It now considers total crashes and fatal-and-injury crashes over 1-year and 3-year periods, providing a more comprehensive safety assessment. Additionally, the new inputs are specific to crash types that are most susceptible to correction by installing a traffic signal (angle and pedestrian), as shown in the figure below:

Warrant 7 Crash Experience - new inputs

Warrant 8: Roadway Network

This warrant applies when a traffic signal can help encourage the concentration and organization of traffic flow within a roadway network. It considers the strategic importance of the intersection in the overall road network to enhance traffic management.

Warrant 9: Intersection Near a Grade Crossing

This warrant applies to intersections near a grade crossing, where one approach is controlled by a STOP or YIELD sign at a highway-highway intersection. It evaluates both traffic volume and the physical characteristics of the roadway to determine the need for a signal installation.

After entering the intersection data, HCS 2025 generates a final report that provides an overview of the intersection characteristics and indicates which warrants are met. The formatted report simplifies the review process, making it easier for professionals to assess the need for a traffic signal, review and submit the traffic study. The next Figure shows an example of the check list provided in the software report.

Warrant 4 Pedestrians - new inputs in HCS

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