Chapter 3 Use Cases

The project team identified seven major work zone technology use cases that could encompass the currently available work zone technologies:

1. Traveler Information Systems (Speed and Travel Time)
2. Queue Warning Systems
3. WZIAS
4. Work Zone Presence/Layout
5. Speed Harmonization Systems
6. Speed Compliance Systems
7. Dynamic Merge Assistance Systems

The following section describes, briefly, each of the use cases and the level of maturity of Smart Work Zone technologies in each of those use cases. The goal of this effort was to develop a practitioner guide for emerging technologies that are not already mature. Maturity in the case of this guide was defined as the readiness of the approach for scaled-up deployment of the Smart Work Zone technology. The FHWA Technology Readiness Level approach was used to develop this guide, and Smart Work Zone technologies were rated on a four-point scale ranging from 0 to 3 (0 – experimental concept, 1 – basic research and controlled laboratory testing, 2 – pilot tests in the field, and 3 – commercially available). Smart Work Zone technologies in each of the use cases have been further categorized into data generation and data dissemination types. Data generation Smart Work Zone technology refers to Smart Work Zone technologies used to collect and generate data about work zones, such as traffic speed, volume, and other relevant data points. These data are typically collected by sensors, cameras, or other types of monitoring equipment and are used to inform decisions about work zone operations and safety. Examples of procurement language for Smart Work Zone components is provided in Appendix B.

On the other hand, data dissemination Smart Work Zone technology refers to technologies that are used to communicate work zone information to drivers and other road users. This information may include real-time traffic updates, detour information, and other relevant information to help drivers navigate through work zones safely and efficiently. This information can be disseminated through a variety of channels, including variable message signs, mobile applications, CAV technologies, and other digital platforms.

Traveler Information Systems

Traveler information systems provide data to drivers on the travel conditions in a work zone in real time. Data can be generated using probe-data, and infrastructure-based sensors. Data for these systems can be disseminated via a 511 system or other state traveler information systems, DMS, smartphone applications, emails, text messages, or CAV in-vehicle messaging. These systems are often deployed with other systems such as queue warning systems and work zone conditions systems. Traveler information systems can be deployed on all roads. Table 5 summarizes technologies used for traveler information systems, which are rated by maturity.

Table 5. Technology Applicability Summary – Traveler Information Systems

^* 0 = System is still in research and development, or no data were available.

Queue Warning Systems

Queue warning systems inform drivers of the presence of downstream congested traffic based on real-time traffic conditions. Data on traffic conditions, including the formation of queues, length of queue, speed of traffic at work zone approach, etc., could be provided using point detectors (most commonly side-fire radar), crowdsourced private sector probe data, and CAV data. Queue warning systems are often deployed on high-speed roadways, such as interstates and expressways, as conflicts between high-speed approaching traffic and the end of queue are a significant safety concern.

The resulting data about traffic queues may be disseminated in a variety of ways, which has made it challenging to define a standard path. Drivers might be alerted to conditions locally using static signs with warning lights, DMS, or through in-vehicle messaging if CAV radio transmission is available. If the queue warning system is equipped to transmit data to a cloud service, data could be made available to smartphone applications or CAV traveler information systems. At the time of writing, the current Work Zone Data Exchange (WZDx) v4.1 standard does not directly support the management of traffic queue system information. There are data objects that address a generic traffic sensor, but the standard lacks queue metrics specifics and message presentation information that may be derived from queue warning systems. However, there is the potential to add this information to the WZDx in the future.

Depending on the system configuration deployed, queue warnings could be provided as a standalone system or as part of a larger traveler information system that would better support dissemination including fleet vehicles. Table 6 summarizes how possible technologies used for queue warning detection and information dissemination are rated by maturity.

Table 6. Technology Applicability Summary – Queue Warning Systems

^* 0 = System is still in research and development, or no data were available.

WZIAS

Intrusion alarms or alerts allow workers and motorists to be notified of a dangerous threat through audible or haptic notifications. For some devices, sensors placed on the perimeter of a work zone algorithmically determine if a vehicle approaching a work zone is traveling at a speed that puts workers at risk if it cannot or does not slow in time. Commercially available WZIAS have been evaluated and found to have mixed results. In general, there are two types of WZIAS, each defined by its method of detecting intrusions. One type can provide advanced notifications to workers by predicting an intrusion before it occurs. The second type provides alerts to workers after a vehicle enters the work zone’s perimeter. The technologies can be broken down further by the type of technology they employ for detection. Kinematic systems utilize sensors and other monitoring equipment to detect the movement and speed of vehicles entering the work zone. Pneumatic systems use sensors placed on the pavement that are activated when a vehicle passes over them. When a vehicle passes over the sensor, it triggers a signal that activates a warning device. Beyond the method of detection is the method of notification. There are multiple notification mechanisms for how workers are alerted to intrusion threats, such as flashing lights, audible alarms, radio notifications, and personally worn device alerts. Alert mechanisms are not mutually exclusive either, as a redundant mechanism or alert method is often recommended per human factors requirements. Most of these technologies also have both a data generation component and a data dissemination component because they can detect as well as alert users. As noted in the current study and similarly stated by Nnaji et al. (2020) in their systematic review of work zone safety technologies, studies on cost-effectiveness are lacking. Such information requires a DOT to make an investment in a technology as an intervention and provide before and after data. For WZIAS, it may be too soon to expect cost-effective insights. Furthermore, deployment of these technologies may also be limited due to concerns regarding feasibility of use in mobile work zones (Boodlal et al., 2020). Table 7 summarizes technologies used for WZIAS by the type of activation, which are rated across all taxonomy categories.

Table 7. Technology Applicability Summary – WZIAS

^* 0 = System is still in research and development, or no data were available.

Work Zone Presence/Layout Systems

Work zone presence/layout systems detect and disseminate information about the presence and configuration of a work zone to drivers. Most of these systems are capable of both data generation and data dissemination and could be deployed on all roadway types. Table 8 summarizes technologies used for systems that detect work zone presence, which are rated by maturity.

Table 8. Technology Applicability Summary– Work Zone Presence/Layout

^* 0 = System is still in research and development, or no data were available.

Speed Harmonization

Work zone speed harmonization systems, including variable speed limit (VSL) systems, broadly attempt to (1) provide guidance on appropriate safe speeds based on current conditions and (2) encourage more uniform speed selection, thereby improving flow and safety. To achieve these goals, recommended speeds are usually set dynamically based on current work zone and congestion conditions. Most current field deployments of work zone VSLs/speed harmonization systems have relied on a series of point detectors to collect data used to define recommended speeds. CAV-based speed harmonization has been examined on a more limited basis through simulation efforts and limited field tests. Most field deployed systems provide information on recommended speeds through dynamic speed limit signs placed at fixed locations and supplemental websites, but emerging CAV approaches provide in-vehicle guidance and control.

The current state of the practice is to deploy speed harmonization systems on specific projects where operational or safety issues are expected. These systems have been deployed and evaluated on freeways; no arterial applications were identified. Table 9 summarizes how possible technologies used for speed harmonization information generation and information dissemination are rated across all taxonomy categories,

Table 9. Technology Applicability Summary – Speed Harmonization

* 0 = System is still in research and development, or no data were available.

Speed Compliance Systems

Speed compliance systems monitor vehicle speed using radar to track passing vehicles at the location where it has been deployed. Within a work zone, these systems can be deployed for both advisory and regulatory purposes. In the case of the advisory system, a VSL message sign or speed feedback trailer provides a digital readout of approaching vehicle speeds that updates as each vehicle passes. Most advisory message signs also flash when the speed exceeds a speed limit threshold or may switch to a “slow down” message depending on the product brand. When deployed for regulatory purposes, the system will utilize photo enforcement technology to read the license plate and transmit violation information to a back office administrative system that will issue citations to the owner of the violating vehicle. Regulatory speed compliance systems are most effective when signage is deployed upstream of the system location indicating that photo enforcement is in effect withing the work zone. The use of photo enforcement speed compliance systems is not legal in every jurisdiction, so there may be limitations on the application of this technique. Table 10 summarizes technologies used for systems that detect work zone conditions, which are rated by maturity.

Table 10. Technology Applicability Summary – Speed Compliance Systems

^* 0 = System is still in research and development, or no data were available.

Dynamic Merge Assistance Systems

Work zone dynamic merge assistance systems attempt to (1) provide guidance on lane usage based on real-time work zone and traffic conditions or (2) encourage smoother merging by creating appropriate gaps, thereby improving work zone throughput, reducing traffic congestion, and mitigating safety concerns. To achieve these goals, recommended merge strategies (e.g., early or late merges) are usually activated dynamically based on real-time work zone and traffic conditions. Current field deployments of work zone dynamic merge assistance systems usually rely on a series of traffic sensors to collect data to determine corresponding merge strategies. CAV-based dynamic merge assistance has been evaluated on a more limited basis, mostly through simulation efforts and limited field tests. Most field deployments disseminate merge strategy information using both (1) static signs with dynamic flashers and (2) DMS placed at strategic locations. Emerging CAV-based approaches, on the other hand, provide either in-vehicle guidance (for human-operated vehicles) or governance over the cooperative merging process (for autonomous vehicles). The current state of the practice is to deploy DMS with supplemental static signs (equipped with dynamic flashers) at work zones expected to have operational issues. These systems have been deployed and evaluated on both freeways and arterials. Table 11 summarizes possible technologies used for dynamic merge assistance information collection and information dissemination rated by maturity.

Table 11. Technology Applicability Summary – Dynamic Merge Assistance

^* 0 = System is still in research and development, or no data were available.

Application of Emerging Technologies in Smart Work Zone Use Cases

The guide is focused on emerging Smart Work Zone technologies that had a maturity rating of less than or equal to 1 or Smart Work Zone technologies suggested by stakeholders who participated in the pre-guide development workshops. The team has chosen two technologies based on each use case, which are discussed below.

Traveler Information Systems

CAVs

Connected vehicle technologies have been used to disseminate information about work zones to approaching drivers. In Wyoming, a connected vehicle pilot program used traveler information

messages and showed that they reduced deceleration rates and lowered crash risk (Yang et al., 2020). Further, Misra et al. (2018) found that vehicle-to-infrastructure (V2I) and infrastructure-to-vehicle (I2V) communication could be more effective than vehicle-to-vehicle (V2V) communication by providing state DOTs with the ability to send tailored in-vehicle messages to drivers. Finally, a driver smart assistance system alerted drivers of an approaching work zone by sending alerts in auditory and visual modalities via radio frequency identification, which resulted in reduced speeds and helped prompt vehicles to decelerate sooner (Qiao et al., 2014). Most of the CAV deployments for traveler information systems are in experimental or pilot testing stages.

Crowdsourced Data/Smartphone Applications

Some of these technologies—email alerts, text messages, social media, Commercial Navigation Apps, websites, and media alerts—can also be used to provide information to travelers about work zones. In general, these technologies make it easy to disseminate information and are low-cost solutions. These systems are commercially available and well understood by state DOTs. However, they are also limited by access and availability of infrastructure to send the data. For example, a person may need to be subscribed to an email alert or text message option to be notified of the information or, in the case of a website, need to be aware of the website, or they may need to have the app installed on their cell phone and have internet access to be able to access traveler information.

Queue Warning Systems

CAVs

CAV-based queue warning systems have been proposed in the literature, but few field evaluations exist. In CAV-based queue warning systems, the vehicles themselves act as probes on the traffic stream. The speeds from equipped vehicles are then used to detect the existence of a traffic queue or significant speed differences. A CAV-based queue warning can be executed by either V2V communications among vehicles in the vicinity or reporting speeds to an IOO, which then creates and disseminates warnings via V2I communications. To date, V2I systems that have relied on CAVs to generate the data for the queue warning system have only been examined via simulation, as the market penetration rate for CAVs has been insufficient to do field tests where the vehicles serve as the data collection tool. Although most V2V systems have been evaluated with simulation analysis, a few field evaluations of V2V-based systems, in the form of rear-end collision warning systems, have been identified (Khazraeian et al., 2017; Stephens et al., 2015; Zhao et al., 2019).

CAV-based systems are still in an experimental stage. The CAV market penetration rate remains low, and the required penetration to support this application remains unclear. As a result, the ability to directly use CAVs to generate data for queue warning is still limited. While using CAVs as a data source for queue warning is currently experimental, it has a great deal of promise as market penetration increases because data generation would not be tied to specific physical locations where sensors are deployed. Khazraeian et al. (2017) found a 3% to 6% market penetration rate would yield accurate queue warnings, and the CAV-based estimation of the back of the queue on a congested freeway can provide a more accurate location than that based on detectors. Texas A&M Transportation Institute conducted a demonstration with 21 CV-enabled vehicles showing that queue warning using CAV technology can locate the end of queue more accurately than loop detectors with a 1-mile spacing (Stephens et al., 2015). This could provide a long-term robust way to identify traffic queues approaching the work zone.

Crowdsourced Data/Smartphone Applications

Queue warning functions in smartphone applications are rarely standalone applications. Instead, they are usually part of navigation software that provides broader traveler information and routing functions. Navigation applications on smartphones are a well-developed commercially available technology with multiple vendors. The smartphone user can install the navigation software directly from the app marketplace, usually at no cost, but not every user may have the software installed or be actively using it when approaching a work zone. The queue warning function, as part of the navigation software, is available not only at the pre-trip planning stage, but also throughout the trip if an internet connection is available. Being a data element within navigation software, the queue warning function integrated with the navigation software can easily provide comprehensive information from local work zone conditions, alternative routing, and suggested departure times. However, no explicit studies of the effectiveness of these systems on preventing end-of-queue crashes could be located. Because this dissemination method requires no physical devices being deployed onto the road, the queue warning on smartphone applications works under all traffic conditions at any sites, given an internet connection is available. It has been observed that drivers trust navigation software on their mobile devices, and as drivers often follow the detour suggested by a navigation app, significant traffic pattern shifts may be observed.

WZIAS

Smart Vest

Smart Vest technologies are evolving rapidly and can describe both the vest itself or a wearable device carried in a vest pocket. These systems can identify intrusions; track vehicles, equipment, and personnel; and consider potential collisions based on trajectory (Mollenhauer et al., 2021). Smart Vests are very new pieces of technology, whose evaluation is still ongoing (Maturity = 1). The vests employ an algorithm to communicate potential collisions to workers, passing drivers, and CAVs. Human-machine interface (HMI) modes utilize flashing lights for visual signaling, vibrations for haptic signaling, and speakers for auditory signaling. A receiver provides RTK GPS localization, and a communication module transmits between the vest and the gateway that houses the algorithm. This module sends algorithm-based RTK GPS data and HMI requests to activate the sensors on the vest. The gateway also interprets work zone boundaries through a polygon plot. The vest features a low-level warning when within 1 meter of a work zone boundary and a high-level warning when the boundary has been reached or crossed. Field testing was conducted in Elliston, VA, at an active construction site, where it was verified that the communication range was operational in a zone with a 500-meter length (Mollenhauer et al., 2021).

Traffic Guard Worker Alert System

The Traffic Guard Worker Alert System (TGWAS, or WAS) uses a pneumatic detection system and provides auditory, visual, and haptic alarms. It is a commercially available system, but so far has been evaluated only in limited pilot deployments. Astro Optics advertises the device as having a 1,000-ft. range, but specifies that the device is a “Warehouse Audible” system, suggesting the device is marketed for an indoor environment as opposed to an outdoor highway work zone environment (Worker Alert System, n.d.). If a vehicle drives over a pneumatic tube positioned at the perimeter of a work zone, the alarms are triggered, including an audio alarm that achieves 80 decibels at a span of 50 feet (Boodlal et al., 2020). Eseonu et al. (2018) found that workers operating noisy equipment are unable to hear the alarm.

Work Zone Presence/Layout

CAVs

Typically, warning drivers of an approaching work zone or end of queue ahead can be done with I2V systems. Parikh et al. (2019) described this technology as able to warn approaching CAVs about upcoming work zones by providing advanced warning to approaching drivers about obstructions, lane shifts, lane closures, speed reductions, or maintenance vehicles entering or exiting a work zone area. Most of the work in this domain is still ongoing at an experimental capacity.

Crowdsourced Data/Smartphone App

Commercial Navigation App technologies allow information to be either manually or automatically collected and shared with a large number of people who also enlist the services of the technology. These technologies have been deployed successfully for over 10 years, and the near ubiquitous use of smartphones has made it easy to collect data with minimal effort. Some crowdsourcing applications allow users to opt in regarding the information they share, while other applications capture information without the user’s direct knowledge. In general, these applications allow information to be regularly updated and curated by the public. Some services analyze the environmental aspects of the data, including road inventory and work zones, for organizations to use in their asset management. For work zones, the application detects the presence of cones and aggregates the information where it can be accessed and monitored via an application programming interface. Studies in non-work zone locations have shown that these crowdsourcing technologies have resulted in traffic incidents being identified 10 minutes sooner, a 30% decrease in vehicle crashes, and a 24% to 27% decrease in traffic delays (Amin-Naseri et al., 2018; Waze, 2020). These crowdsourcing technologies can be used by traffic management centers or third-party providers to update road users about lane closures or other changes to work zones along their route. Further, crowdsourcing features include the ability to upload images and select traffic conditions such as crashes and traffic queues in active work zones as well as lane activity conditions, including an open, restricted, or closed lane (Adu-Gyamfi et al., 2019).

Speed Harmonization

CAVs

CAV-based speed harmonization systems have been proposed in the literature, but few field deployments have been conducted. In CAV speed harmonization systems, the vehicles themselves act as probes on the traffic stream. The speeds from equipped vehicles are then used to generate recommended travel speed to optimize flow and safety. CAV-based speed harmonization typically involves reporting speeds to an IOO, which then generates a recommended speed that is transmitted via V2I communications. To date, systems that have relied on CAVs to generate the data for the speed harmonization system have only been examined via simulation, as the market penetration rate for CAVs has been insufficient to do field tests where the vehicles serve as the data collection tool (Ghiasi et al., 2019; Hale et al., 2016; Jiaqi Ma et al., 2016; Ramezani & Benekohal, 2015). Those studies found widely varying results for the market penetration of CAVs required to generate system benefits, ranging from a low of about 10% (Hale et al., 2016) to a high of 80% (Ramezani & Benekohal, 2015). The most widely reported CAV-based speed harmonization field test used three CAVs as data collectors and provided automated speed control, but the actual data collected to set the recommended speeds were from roadside radar trailers (Hale et al., 2016; Ramezani & Benekohal, 2015).

CAV-based systems are still in an experimental stage. The market penetration rate of CAVs remains low, and the required penetration to support this application remains unclear. As a result, the ability to directly use CAVs to generate data for speed harmonization is still extremely limited. While using CAVs as a data source for speed harmonization is currently experimental, it has a great deal of promise as market penetration increases, as data generation would not be tied to specific physical locations where sensors are deployed. This could provide a long-term robust way to characterize flow approaching the work zone taper and throughout the work zone.

Smartphone Applications

Mobile applications and internet sites have also been used to share information from VSL/speed harmonization systems with road users, but they are not as prevalent as the use of VSL signs. These methods typically show a display that duplicates the speeds that are displayed on the field VSL signs, so they are not the sole means by which information on VSLs is distributed. Websites showing work zone conditions are provided by some commercial vendors. Likewise, some DOTs will archive and share information about real-time messages through online data portals for ingestion by state traveler information websites or other third-party sites. Mobile applications have been developed for VSLs deployed for active traffic management purposes, but no example of work-zone-specific applications was found.

Website-based platforms for information sharing are commercially available and well understood by agencies. No studies were located that determined the effects of disseminating data using these platforms, but they are expected to create relatively small behavioral changes because they are mirroring the information provided by the VSL signs. The information provided is accessible to everyone and can be accessed enroute or pre-trip. The information used to populate these sites is derived almost exclusively from Smart Work Zone systems where sensors and signs have been placed, so they are limited to locations where there is supporting infrastructure.

Speed Compliance Systems

CAVs

CAVs can be used to reduce speed for drivers approaching work zones using roadside units to broadcast alerts (Parikh et al., 2019). A simulator study conducted by Whitmire et al. (2011) showed that in-vehicle warnings in connected vehicles can increase driver speed compliance, and these warnings are more effective when used in audio and visual modalities. Use of CAVs for speed compliance in work zones is still ongoing in an experimental capacity.

Speed Safety Camera Systems

While speed safety camera systems have been available for some time, they may be considered emerging technologies because legal and institutional barriers to deployment in many jurisdictions have prevented their widespread adoption. As such, they can be categorized as an emerging technology, as there has been some evidence to suggest effectiveness, but there have been limitations as to where they may be deployed. Therefore, speed safety camera systems cannot be fully assessed and suggested as mature technologies. Speed safety camera systems use sensors such as radar or cameras to identify and capture images of vehicle license plates and/or drivers who are traveling over the speed limit. Speeding citations are then mailed to the vehicle’s registered owners. These systems have been used successfully by several state DOTs to reduce traveling speeds in work zones. For example, speed safety camera systems in Illinois have reduced the average travel speed by 4 to 8 mph (Benekohal et al., 2008). Furthermore, in Maryland, the percentage of vehicles exceeding the speed limit dropped from 7% to 1% after these systems were

implemented (Franz & Chang, 2011). More recently, in 2021, the Pennsylvania DOT reduced the total percentage of speeding vehicles in Automated Work Zone Speed Enforcement work zones to 18% to 20% on average from an average of 30% to 35% at the start of the program in 2020 (Pennsylvania DOT, 2022). These systems can work in any deployed stationary work zones, although installing cameras and radar sensors at mobile work zones might be problematic. The data generated from these systems are only available where they are deployed and typically only available to the agency that deploys them. Speed safety camera systems can be deployed with the resources available to state DOTs, but it should be noted that implementing these systems requires collaboration and involvement of multiple government stakeholders, such as law enforcement, the judiciary, and others (Douma et al., 2014).

Dynamic Merge Systems

CAVs

The CAV approach to disseminating dynamic lane merging guidance involves both notification and vehicle control. In this approach, an IOO would provide work zone event information, potentially via a unified data exchange format (e.g., WZDx). This work zone event information would be transmitted to vehicles approaching a work zone using I2V communications. In the dynamic lane merging assistance application, data dissemination using the CAV approach can be broadly grouped into (1) in-vehicle notification that relies on human intervention to conduct the merging process and (2) cooperative lane changing/merging control that executes the merging process automatically using Advanced Driver Assistance Systems (ADAS). In the first group, CAVs in the closed lane can receive notifications regarding the presence and location of the work zones, while drivers in the open lanes are asked to cooperate and smooth the merge through in-vehicle notifications. A primary benefit of this approach is that it can accommodate mixed traffic conditions that consist of both autonomous and human-operated vehicles. In the second group, while assuming a 100% market penetration, the work zone merging traffic receives a full suite of CAV benefits, including reduced gaps, increased throughput, and a system-optimal merging plan, made possible by full cooperative merging and not reliant on voluntary compliance. However, most systems have only been tested using simulation due to the low market penetration of CAVs.

Several studies have proposed and evaluated the effectiveness of various CAV-based work zone lane merging strategies. Many simulation/modeling studies found that the cooperative control strategy can improve both work zone capacity and safety at 100% of cooperating vehicles. For example, Cao et al. (2021) found from a simulation study that by assuming a 0.5-second headway, a three-to-one lane closure work zone can experience a more than 50% reduction in mean travel time with CAV technology. Other studies explored how the market penetration rate affects traffic safety and mobility (Algomaiah & Li, 2021, 2022; Liu et al., 2017). Liu et al. (2017) concluded that the number of merging conflicts decreased with increases in the ADAS penetration rate. Their simulation study found a 7.2% decrease in conflicts as the penetration rate increased from 20% to 50%. Conflicts decreased by an additional 4.3% as the penetration rate grew from 55% to 90%. Note that varying results in mobility performance were widely reported in the literature, ranging from a 1.5% decrease in throughput with 90% ADAS market penetration (Liu et al., 2017) to a 45% capacity increase from an optimized central trajectory planning cooperative merging scenario (Algomaiah & Li, 2022).

Using CAVs to provide dynamic lane merging assistance is still in the experimental stage. Most data available on this approach come from simulation studies, and impacts varied significantly between studies. The deployment and field evaluation of these systems are contingent upon having

enough market penetration to support the application. A CAV-based lane merging assistance system has obvious potential advantages because it does not require physical roadside signs to share information with drivers. This enables continuous merging recommendations over the course of a work zone and potentially improves flexibility, especially in cases where a work zone might be for a short duration or experience phasing changes. Furthermore, cooperative lane merging integrated with ADAS will likely create greater safety and mobility effects, as the system will no longer rely on driver compliance with recommendations.

Smartphone Applications

Lane merging assistance functions on smartphone applications are rarely standalone applications. Instead, they are usually part of navigation or traffic and traveler information applications. These navigation or traveler information apps on smartphones are a well-developed commercially available technology with multiple vendors. The navigation software can be installed by the smartphone user directly from the app marketplace or accessed directly via software website, usually free of charge. However, not every user may have the software installed or be actively using it when approaching a work zone. One challenge with disseminating dynamic lane merging assistance information is that the merging strategy changes with real-time traffic conditions, and pre-trip information may be obsolete when the motorist arrives at the work zone. Therefore, most navigation systems include only static work zone data elements (e.g., work zone locations), but not dynamic lane merging information. Because this technology requires no physical devices to be deployed onto the road, the lane merging assistance function on smartphone applications, if available, works under all traffic conditions at any sites given an available internet connection. No studies were identified that determined the effects of disseminating dynamic lane merging information using smartphone app platforms.

Additional Resources

In the review of the literature and discussions with stakeholders, the team identified the following resources and personnel at state DOTs who are implementing these Smart Work Zone systems:

1. Work Zone Management Guidebook
   • MN DOT, March 2021
   • Link: https://epg.modot.org/files/6/6b/909_WZM_Guidebook.pdf
2. Smart Work Zone Guidelines, Design Guidelines for Deployment of Work Zone ITS
   • Tx DOT, October 2018
   • Link: https://ftp.dot.state.tx.us/pub/txdot-info/trf/smart-work-zone-guidelines.pdf
3. Connecticut Department of Transportation, Smart Work Zone Guide
   • CT DOT, April 2017
   • Link: https://portal.ct.gov//media/dot/documents/dhighwayoperations/its/april2017ctdotsmartworkzonesguidepdf.pdf
4. Work Zone ITS Implementation Guide, Use of Technology and Data for Effective WZ Management
   • FHWA, January 2014
   • Link: https://ops.fhwa.dot.gov/publications/fhwahop14008/fhwahop14008.pdf
5. Work Zone Intelligent Transportation Systems - Technology Supplement
   • FHWA, September 2021

5. • Link: https://ops.fhwa.dot.gov/publications/fhwahop21021/fhwahop21021.pdf
6. Identification of National Work Zone Safety Objectives and Activities: Summary Report
   • FHWA, March 2023
   • Link: https://ops.fhwa.dot.gov/publications/fhwahop22059/fhwahop22059.pdf
7. FHWA Resources
   • Link: https://ops.fhwa.dot.gov/wz/outreach/wz_training/wz_guides_documents.htm
8. Work Zone Safety Information Clearinghouse
   • Smart Work Zones Technology Applications
   • Link: https://workzonesafety.org/topics-of-interest/smart-work-zones/