CHAPTER 3

Planning TPIMS

This chapter focuses on the necessary planning-level decisions for transportation agencies to make before design can commence. While all chapters touch on a critical phase of building a successful TPIMS program, many of the decisions described in this chapter have direct implications for efforts covered in subsequent chapters.

The subsections of Chapter 3 discuss the following actions as steps for fully planning a TPIMS:

• Identify a TPIMS Business Model.
• Screen and Select Eligible TPIMS Sites.
• Select a Count Methodology.
• Review and Choose a Preferred Data Processing Solution.
• Strategize Methods for Information Distribution.
• Discuss Operational Policies.
• Identify Other Considerations.

In this chapter, agencies will consider a series of decisions for the planning and development of the proposed TPIMS deployment that could interplay with subsequent chapters in this Guide. Throughout the process, stakeholder engagement is crucial for achieving program success. Identifying key stakeholders was introduced in Chapter 2, and these organizations or individuals will aid in defining or clarifying objectives and preferred approaches. Engaging stakeholders is essential for effective outcomes, which begins with the planning steps described in Chapter 2 and continues in this chapter, where stakeholders are expected to provide input on key planning and operational decisions. In addition to the transportation agency, the key stakeholder groups that should be involved include representatives of the trucking industry, truck drivers, truck stops, and enforcement agencies.

Within a transportation agency, the TPIMS champion or project lead must identify which units (offices, bureaus, teams, etc.) need to be involved in the planning and development of the proposed TPIMS deployment. The greater the influence a champion brings in an organization, the more likely TPIMS will be integrated into early planning processes. An effective champion understands the issues surrounding truck parking and can leverage resources toward improvements.

The success of the TPIMS requires early input and buy-in from multiple units that may have responsibilities ranging across planning, design, IT, legal, procurement, operations, public relations, or maintenance. If freight-related technology applications are new to an agency, it is important for staff to be mindful of the dynamics among personnel representing freight planning, enforcement, data systems, and so forth, as these groups may not have much history of collaborating. Given the complexity and longer-term nature of developing and implementing TPIMS, intentional collaboration is critical to program success.

There are several key organizational components in the development of internal agency collaboration as well as regional, multistate collaboration. These include an awareness of a shared problem, agency leadership that are active champions of the project, agency organizational structure and committees that support collaboration, active communication throughout the project, and collaborative planning and budgeting to create transparency and partnerships. These factors may be defined in multistate memorandums of understanding.

Organizational and leadership continuity is also critical for TPIMS. Providing for continuity and institutionalization of TPIMS within and across agency partners provides for continued support and investment in TPIMS.

Further, it is vital to acknowledge the disparities between public and private sectors in truck parking. Private-sector truck parking, which dominates the United States, operates differently and is hesitant to collaborate with the public sector due to capacity concerns. Truck stop operators see parking as a financial burden due to the lack of revenue generation, while public-sector infrastructure owners cannot generate commercial income from their facilities. Understanding these differences is crucial for transportation agencies to engage with these groups effectively and align their approach with private-sector motivations, ensuring successful partnerships.

Identify a TPIMS Business Model

One of the first decisions for an agency to make in implementing TPIMS is to select a business model that best fits an agency’s needs and is aligned with the purpose of TPIMS. For many agencies, this step will entail deciding between a public and a public/private model. The two broad model categories are discussed in greater detail below but may generally be characterized as an agency fully owning and operating the TPIMS for the public model versus a private-sector partner owning and/or operating some component of the TPIMS in the public/private model. Prior to embarking on a TPIMS effort, it is important to evaluate which business model might be most appropriate. A public-sector agency may have certain requirements for how TPIMS can be procured, operated, and maintained, whereas a private-sector group may have greater flexibility and fewer institutional barriers. In general, both the public sector and private sector can either have distinct owner and/or operator responsibilities over the entire TPIMS system, or they can both participate in a partnership.

Public Model

In the public-sector model, an agency fully owns and operates the TPIMS. This includes the truck parking facility as well as the ITS devices that comprise the TPIMS subsystems. In deploying TPIMS using this model, an agency may either own a parcel of land on which it constructs a new truck parking facility equipped with TPIMS or deploy TPIMS at an existing truck parking facility. Among the TPIMS deployments in the United States, the public model is one of the most common. Wisconsin, Minnesota, Florida, and Colorado all provide examples of states that have followed the public model.

Public/Private Partnership Models

An alternative to the public model is the public/private model. The FHWA’s 2022 Truck Parking Development Handbook observed that truck parking is an appropriate public/private candidate because it sits at the nexus of public interest and private industry operations—when truck parking is adequate, safety and mobility are improved, as is the economic competitiveness of private industry (FHWA 2022). For some agencies, the public/private model may be preferred as it offers

The 2022 South Carolina Statewide Truck Parking Assessment Study offers further guidance on selecting a business model through the development of a screening tool for evaluating and developing truck parking partnerships. The tool provides a high-level description of the proposed partnership approach, including the types of contractual partners. It goes on to provide screening factors, which are criteria for evaluating each of the potential partnerships. Each factor identifies aspects of a potential truck parking partnership that are critical for the achievement of an agency’s goals. They include the following screening factors, along with critical questions posed by each factor:

• Policy Goals. How well does the proposed partnership address specific truck parking policy goals? Can the partnership address specific truck challenges that have been identified through planning activities?
• Organizational Capacity. Are there internal champions for the specific partnership within the agency? Does the agency have access to sufficient internal and external technical resources to successfully manage the partnership in the public interest? Has the agency established guidelines and regulations for procuring and managing the partnership?
• Legal. Is there legal authority to pursue the proposed partnership? Are there certain legal structures that would be more appropriate for the partnership? Who would need to provide approval for this potential partnership, and what would be the parameters?
• Public Support. Can sufficient support from stakeholders be achieved to pursue the project? Can sufficient political support be achieved for delivering the project?
• Risk Allocation. Would the partnership provide cost-effective opportunities for the appropriate allocation of key risks between the partners? What would be key responsibilities that the agency could retain, and what are the associated risks? What would be the key responsibilities that the agency would seek to allocate to a partner, and what are the associated risks?
• Financial Viability. What are the near-term and long-term cost requirements? Would the results of the partnership’s efforts potentially include scenarios that could involve revenue generation? Are there federal, state, or local funding sources that can support the cost requirements? Would the potential partner be responsible for providing any funding sources that can support the cost requirements? (South Carolina Department of Transportation 2022)

These South Carolina DOT screening factors and the critical questions posed can be useful to any agency selecting an appropriate TPIMS business model. Partnerships with the private sector, including drivers and truck stop operators, are also critical to the success of a TPIMS. Truck operators offer grounded experience in understanding parking needs and constraints, and truck stop operators should be included when agencies are working to expand TPIMS, given these private facilities’ potential roles in long-term partnerships.

Other Considerations

There are other considerations for an agency to keep in mind when selecting a TPIMS business model. For instance, there is the potential to include other public and private partners beyond state DOTs and truck stop operators. For example, U.S. DOT could be a potential partner as several U.S. DOT truck parking grants have been used by truck stop operators to successfully expand parking capacity. This arrangement effectively creates a joint powers agreement whereby federal funds are used to construct new capacity, and the private sector agrees to manage and maintain the parking spaces for a set amount of time. Academic institutions have also served as public-sector partners as the nation’s first TPIMS was codeveloped with the University of Minnesota, and the Virginia Tech Transportation Institute has been involved in several truck parking projects.

Mobile applications and other technology companies may also serve as private-sector partners. Smartphone applications can serve as a variation of TPIMS that are created and managed by

The following list identifies the primary parking types that have been supported by TPIMS, with additional detail provided in Table 3:

• Public-Sector Rest Areas, Weigh Stations, Welcome Centers, and Truck Parking Lots. These are among the most common truck parking facilities that a public-sector agency will provide. As such, these facilities are often featured in business models run by the public sector and are offered as a free service to the community. That said, several truck parking research efforts have documented the different needs and expectations that truck drivers have for public truck parking facilities.
• Private-Sector Truck Stops and Truck Parking Lots. These private-sector facilities are among the most common truck parking facilities in the United States. They can include a mix of free or paid services for truck parking, which can impact which TPIMS models, if any, are used.
• Mixed-Use Truck Parking Lots. This refers to cases where parking lots designed for one purpose (e.g., a stadium or retail center) also make parking available during certain times for trucks. This is still an emerging practice but could increase the availability of truck parking in areas where they are properly zoned. Since this parking lot type often provides services for a fee, it often falls best under a private-sector TPIMS business model, although public-sector models could also accommodate these types of lots outside of the federally funded portions of the interstates.

Short-term parking areas such as curb spaces and staging areas are not addressed in this Guide, as they offer limited utility in planning truck parking for purposes of safety, rest, or HOS compliance. Curb space truck parking often focuses on short-term parking activities (e.g., loading and unloading), and staging operations tend to focus on facilities that are close to an intermodal facility or distribution center.

Table 3. Truck parking facility types.

It is important for public agencies to recognize that these various parking models, to date, have required very different technology solutions in order to collect and report availability, so the parking model decision will heavily influence the technology system requirements necessary for the system to function properly.

Select a Count Methodology

The selection of a count method is often one of the most critical decisions for a TPIMS provider to make, as its selection will dictate a menu of capital, operations, and maintenance costs necessary to achieve a certain level of accuracy. Understanding this key decision helps inform the planning and design phases.

Various count methods exist for assessing truck parking availability, each has its own set of advantages, disadvantages, and applications. Understanding how this planning-level approach impacts the downstream elements of TPIMS is critical for ensuring that the system is set up for success. Similar to the selection of parking locations, the selection of a particular technology

The following provides an overview of the benefits, drawbacks and common use cases for the four TPIMS count methods described in Table 4:

• Entrance/Exit Count Method. This method is often most appealing because it typically incurs a lower average cost and footprint to install radars, beams, or microwave systems (see Figure 8). However, it is also prone to errors from miscounting since there is no verification that trucks are parking in their actual spaces. Increasing data accuracy with this method requires frequent monitoring by the operating agency.
• Space Occupancy Count Method. This method is often considered more reliable as it comprehensively assesses whether spaces are being utilized (see Figure 9). The technologies required to operate this method are often more costly overall due to the size of the monitoring area, and—with some technologies—it may not provide coverage of areas that are not officially marked for parking but are still considered viable parking spaces by truck drivers.
• Digital Occupancy Count Method. This method is often found among reservation-based systems that allow truck drivers to select a parking spot. With reservation systems often being a for-profit business model, it is not usually found in public-sector parking facilities and it requires the maintenance and operation of a reservation system. New street-side metered parking systems are migrating to this approach.
• Crowdsourcing Count Method. This method is typically low-cost to collect and usually does not involve physical infrastructure for data collection. However, it is often not accurate at parking facilities that do not have frequent or widespread contributions from crowdsource reporters (e.g., truck drivers and facility owners). It also does not provide space count data; most use color-coded (red, yellow, green) capacity estimates.

Figure 8 provides a concept drawing of the “entrance/exit count” method and Figure 9 provides a concept drawing of the “space occupancy count” method; these figures illustrate these counting methods and the technology options for implementing them for transportation agencies interested in pursuing these counting methods.

Review and Choose a Preferred Data Processing Solution

Real-time data that is collected must then be processed to determine the availability of parking at a given lot. This step of the planning process reviews options that are available for data processing and their associated advantages and disadvantages. Public-sector and private-sector data processing options are available and often are driven by predecessor decisions regarding business model, site identification, and (to a lesser degree) count methodology, so it represents the logical next step to undertake. This section of the Guide is intended to help an agency identify the choices that are available. While the preferred alternative may not yet be known, identifying the eligible (and ineligible) options can help structure the TPIMS program and establish requirements. The following technologies are among those that are frequently utilized to process real-time parking data, with additional details provided in Table 5:

• Central/Integrated Software. This is often a public-sector agency using its advanced traffic management system (ATMS) software to manage a TPIMS deployment as part of its ITS program. Similarly, a private-sector group might offer truck parking information to its customers through its own platform, or—in instances of a public/private partnership—send data to the public-agency ATMS. This alternative is best for agencies that prefer to manage their systems in-house and through one primary software tool that can manage the vast majority of operational elements in their transportation system.
• Independent Software. This third-party software is owned by the public-sector agency to process TPIMS data, but it is not part of the ATMS. Similar options exist for private-sector groups, either internally or in partnership with the public agency. This alternative is best for agencies that do not have a central software tool that can accommodate TPIMS, or among

Table 5. Detailed information about parking data processing technologies.

• those who wish to keep the functionality separate, such as instances where the private sector is running TPIMS and providing a data feed to a public-sector agency.
• Software-as-a-Service. This option uses a software-as-a-service (SaaS) operating model, where a third party is contracted to provide data collection and processing services for TPIMS data. Various models exist for this alternative, but it works best for agencies that prefer a third-party entity to oversee the proper function of the system.

Many public-sector agencies are accustomed to one particular approach for data processing, so it is important to review each decision in depth and determine which options are feasible and allowable within a particular organization. The purpose is not necessarily to select a particular software solution but to recognize the options that are feasible and interoperable for this effort. Additional considerations should be given to consider data accuracy requirements and the associated levels of effort required.

Other information processing considerations to keep in mind include data processing and predictive reporting. Maintaining accurate parking availability information is critical for the acceptance of the system by truck drivers. As part of data processing, decision-makers must determine the level of ongoing validation that is both possible for a given organization and required by the

they are along the corridor, along with the available spaces. DMS tend to be more costly than DPAS as they have more dynamic messaging features, are larger in size, and require associated support structures. However, an advantage of DMS is that a transportation agency can use the DMS for messaging other than TPIMS (e.g., during a major emergency the DMS could report on traveler information instead of parking availability).

Web-Based Platforms

Web-based platforms, such as traveler information websites or mobile smartphone applications, are another option available to agencies for disseminating TPIMS information. Web-based platforms enable drivers and dispatchers to make informed route planning decisions at the beginning of their trip as well as en route. These services can share TPIMS data on parking location and availability with truck drivers through a variety of digital mediums.

Traveler information websites, such as 511 programs and smartphone applications, are relatively low-cost ways to disseminate truck parking information. Web-based platforms can display real-time truck parking cameras’ images if CCTV cameras are present at the sites. A smartphone application may sense a vehicle’s roadway heading and global positioning system (GPS) location to present parking availability information to drivers for facilities in proximity to the vehicle’s position and travel path, whereas a website can show all of the available truck parking locations

in its database. One drawback of relying on traveler information systems for truck parking is that the information can only be accessed by dispatchers, drivers with Wi-Fi or data plans and cellular service along the corridor, and vehicles with integrated in-cab systems. More importantly, to ensure safe operations, mobile applications must comply with distracted driving laws and regulations, including FMCSA’s “one-touch” compliance requirement that truck driving mobile applications rely on hands-free, voice-interactive commands.

Other Dissemination Methods

In addition to roadside signs and web-based platforms, agencies have other tools available to them to distribute information on parking availability, which are outlined in the following list. However, in reaching a decision on preferred methods for disseminating TPIMS information, it is important for agencies to consider that these methods are less frequently used in the industry. As a result, they may not be preferred methods for the primary distribution of parking availability information but may serve well as supplements to an agency’s primary dissemination tool.

• In-Cab Systems. Many trucking companies equip their fleet vehicles with in-cab systems that provide applications for navigation and electronic logging devices (ELD) for tracking HOS and fuel optimization, among others. In-cab systems may also disseminate truck parking availability data from an online data feed.
• GPS Navigation Systems. GPS navigation systems may also provide truck parking availability data from an online data feed.
• Highway Advisory Radio. Highway advisory radio, also known as travelers’ information stations, disseminates highway information to travelers via radio. A transportation agency may provide truck parking information via a highway advisory radio station.
• Citizen’s Band (CB) Radio. Individual truck drivers may communicate the availability of truck parking via CB radio.
• Other Radio Options. Satellite radio services and some local radio stations may incorporate truck parking data into their existing traveler information segments.
• Call-in Phone Systems. Using interactive voice recognition (IVR) technology, call-in phone systems can provide truck parking information. A driver who is looking for information would verbally call the IVR system and follow the voice prompts to get the desired truck parking information in a hands-free environment.
• Traveler Information Kiosks. Existing traveler information kiosks at truck stops and rest areas may be adapted to display truck parking information.
• Connected Vehicle Communications. Connected vehicle communications is an emerging technology that could broadcast truck parking information via infrastructure-to-vehicle or vehicle-to-everything messages from roadside units and/or other large-scale communications methods. As of 2022, the deployment of connected vehicles is not common, so the supporting infrastructure is not yet present to facilitate widespread data exchange.

Data Sharing Systems

While the previous discussion primarily focused on technologies that distribute information to truck drivers, it is also important to consider tools that enable data sharing between systems. Ideally, TPIMS systems should provide seamless information to truck drivers across jurisdictional boundaries. As a truck is approaching a state line, being able to receive information on real-time parking availability in the next state is extremely valuable. This requires multistate coordination to ensure that information can be shared and displayed in the most advantageous manner for freight operations. Improving interoperability or sharing TPIMS data across jurisdictions may also benefit intermodal terminal operations or urban curb management for local freight, though more research is needed.

Most agencies routinely share data with other agencies as part of their ITS program. Standards-based data feeds using APIs and central clearinghouses are two methods for effectively sharing data across agencies. A data exchange standard would allow any agency to ingest another agency’s TPIMS data without confusion of what data is being received. For example, as part of the MAASTO TPIMS deployment, one key development was the Regional TPIMS Data Exchange Specification Document (MAASTO 2018). This allowed MAASTO to standardize the data feed containing JSON scripting language so that all third-party application developers could display TPIMS data on their platforms.

Another potential tool is a central clearinghouse, where data from all agencies is consolidated for distribution to private third parties. This approach provides one location to access the data for all agencies and the clearinghouse can also act as a data archive. Another alternative is to use private third parties to obtain data from individual agencies using a consistent data feed format.

It is important, however, to consider the issue of data ownership, especially with regard to private-sector TPIMS providers. When developing the project contract, it is important for DOTs to ensure that data ownership is addressed and that they have free and unlimited access to the data to use as they see fit. This data is important for TPIMS performance analysis, planning, communication, and the project’s continued success.

Discuss Operational Policies

As part of the planning process, a key question for an agency to ask is the following: What are the operational policies to which the TPIMS will adhere? More specifically, it is important for them to ask how reliable, accurate, and timely the information should be. A TPIMS that provides incorrect or outdated parking availability will lose credibility very quickly. Many public agencies face similar challenges with other facets of their ITS program. For example, agencies typically implement policies for how, when, and under what conditions a message can be posted to DMS; policies also outline how information must be verified before posting the message. In implementing TPIMS, it is important for agencies to reexamine existing policies for DMS messaging as truck drivers are likely to be more sensitive to inaccurate parking information (as opposed to inaccurate travel times displayed on a DMS), given the potential legal and safety consequences of being unable to find parking at a designated facility.

Accuracy requirements may be part of a larger set of system requirements developed as part of the systems engineering approach. It is important that these requirements be vetted closely with agency policies and stakeholder needs to make sure that they are reasonable, achievable, and pertinent. While an agency manager will likely state that the system should be “totally accurate,” it is important to know that this may not be feasible without undertaking a substantial cost. Understanding the allowable tolerances will help inform the extent of data infrastructure necessary to publish a sufficiently accurate assessment of parking availability.

Once the operational policies of the TPIMS have been established, it is important for an agency to then adopt metrics by which they may monitor and track the performance of the TPIMS in light of those policies. Without metrics to support operational policies, agencies will be unable to determine if the TPIMS is performing to agency standards and take corrective actions in the event it is not. Some factors to consider when establishing accuracy-related metrics for data reporting include the following:

• Latency. When parking availability is reported some distance from the parking lot, a time-distance gap exists between when a truck driver sees that reported availability and when they reach a facility. An inherent risk will always be that the parking availability will change by the time the driver reaches the lot (which could be as long as an hour, if signed 70 miles away).

• Some of this can be mitigated through proper messaging (e.g., “Spaces Open”) or through use of prediction, though this introduces other risks for reporting inaccurate information.
• Inconsistency. If multiple types of TPIMS data are present (e.g., real-time, predictive, latent crowdsourced information), inconsistent reports on availability might occur, which could impact credibility of the system.
• Reporting on a Full Lot. At some point, a parking lot will be full, and the parking availability will be zero. A risk exists that one truck may depart and another truck driver (who previously was told the lot was full) may pull in and find the empty spot. This may impact credibility, as a truck driver will remember being told that “0” stalls were available when, in fact, they believe they found one. To mitigate these challenges, some agencies with TPIMS have elected to display “LOW” instead of a count when below a certain threshold (e.g., when below two available parking stalls, show “LOW” instead of “0” or “1”).
• Perspectives on Parking Availability. There are differences between what a transportation agency or parking manager considers to be an authorized parking stall versus what a truck driver might consider an eligible parking stall. There may be agency policies or local laws that require a parking stall to be marked in order to be considered eligible; this often discounts other unmarked areas that might be eligible for parking, such as an overflow lot. Truck drivers, however, may view these unmarked areas as eligible sites. When a parking lot is reported to be full (i.e., when all marked stalls are in use), it may impact credibility when the truck driver is able to find space in an unmarked area that is not part of that report.
• Definition of “Real-time” Data and Required Refresh Rates. Transportation agencies will need to select the “goldilocks zone” for data reporting; reporting too often will unnecessarily consume limited bandwidth, and reporting too infrequently will impact credibility with truckers. This update frequency will often drive design requirements for network communications. For example, a cellular modem in an area with poor coverage may not provide an acceptable level of service for a system that must refresh every minute.

Decisions on operational policies must be reached before an agency commences design, as these policies can ultimately impact the system design. Furthermore, decisions made during this step in the TPIMS planning process may require an agency to look back at previous planning-level decisions in order to verify that a particular decision or assumption remains valid with the policy selection. For example, as discussed earlier in this section, certain count methodologies are more accurate than others but may be more costly to implement. If an agency chooses to adopt an operational policy that prioritizes accuracy in “reporting on a full lot,” then they may decide that the more accurate count methodology is worth the trade-off in cost.

In reaching operational policy decisions, an agency may also need to revisit the purpose and need for TPIMS. The circumstances that initially motivated an agency to invest in TPIMS can provide guidance on which operational policies should be prioritized and may even spur an agency to create new operational policies it did not previously consider. For instance, perhaps an agency was initially motivated to develop a TPIMS because they observed increased or higher-than-average HOS violation rates in their jurisdiction. Perhaps they observed that truck drivers frequently park in unauthorized or unsafe locations to meet HOS requirements or to temporarily stage before making pickups or deliveries. In making operational policy decisions, looking back to these initial motivating factors can help an agency develop relevant questions to ask and make choices that are aligned with the purpose and need.

Identify Other Considerations

It is important for transportation agencies to account for other design considerations prior to undertaking the design process, recognizing that TPIMS may or may not operate in a variety of environments. For example, rest stops may be far from urban centers and in areas with limited