Office of Operations
21st Century Operations Using 21st Century Technologies

CHAPTER 3. HOT Lane Implementation and Design

The previous chapters addressed issues related to the planning, design and operational considerations when converting existing HOV lanes to HOT lanes. This chapter is intended as guide to all aspects of the implementation phase from project organization, procurement and financing through construction.

Figure 3-1: Stages of HOT Lane Project Development

This graphic shows five Key Stages of HOT lane project development

The remainder of this section discusses the various elements of the key stages of project development necessary to convert an existing HOV lane facility to HOT lane.

3.1 Organization and Management

3.1.1 Participation

There are several transportation organizations that can successfully plan, build, operate and manage an HOT lane program. The specific organizational and management structure may differ based on a variety of factors: state enabling legislation, asset ownership, project financing (e.g., revenue bond or general funds), and the role of the state DOT, regional planning organizations (RPOs) and metropolitan planning organizations (MPOs) in the region. It is important to identify the players involved in the HOT lane implementation process and describe their roles and responsibilities. In addition, it is important to establish an interagency framework that enables their participation.

Described below are entities that should be involved in the planning and implementation of the program:

  • Owner: agency that legally owns the HOT facility and right of way, usually the state Department of Transportation (DOT).

  • Sponsor: the agency with responsibility for overall project planning, design and implementation (Note: the sponsor can be the same as the owner but may be a separate transportation agency).

  • Operator: the organization responsible for the operations and management of the HOT lane facility (Note: the operator can be the same as the owner and sponsor but may be a different organization).

  • Interfacing organizations and institutions: There are several other agencies, including those involved in the development, implementation and operation of the HOT lanes. Examples are:
    • Emergency Services and Incident Management: The HOT lane system will need to interface to these services and coordinate provision of incident management and emergency management services. Decisions must be made on which entities are responsible for control of lanes in emergency and incident situations and protocols and interfaces must be established.
    • 511 and other information services, including Web based links to regional traffic information. Traveler information should be provided on a local and regional basis on the HOT lane operation.
    • State DOTs who may govern policy and in some cases own or operate the roadway or intersecting roadways.
    • Intersecting roadways - There will be temporary impacts to these roadways during construction and more permanent impacts due to changes in traffic patterns resulting from the HOT lanes that need to be coordinated with intersecting roadways. Also, advanced signage for the HOT lanes will need to be placed on these roadways.
    • Regional Interoperability Groups - As discussed below, depending upon the state or region in which the planned HOT lane is located, the Sponsor will most likely need to work with the regional group (e.g., SunPass, E-ZPass, CTOC) in order to use a transponder technology that has regional penetration.
    • MPOs and RPOs – These organizations may be involved only in elements of planning in some cases and in other cases may take a more active role in the regional implementation of HOT lanes and related programs.
    • Stakeholders – Stakeholders including local, regional and state government agencies, interested parties and the general public must be considered at appropriate points in the implementation.

3.1.2 Organization and Management Plan

Early in the planning and implementation process, it is strongly recommended that the interim sponsoring agency establish an organization and management plan. At a minimum, the organization and management plan should identify:

  • Roles and responsibilities;

  • A detailed responsibility matrix that clearly identifies each element of work and varying responsibilities associated with that work element (e.g., who has direct responsibility, support responsibility);

  • An overall program schedule (developed under this process or another related process); and,

  • A communication and meeting plan to establish how the project team will interact, obtain consensus and approvals and what types and frequencies of meetings can be expected.

This plan will evolve and should be updated periodically as the project moves toward implementation. In order to ensure transparency, the organization and management plan should be reviewed and approved by each of the entities directly involved in the project.

3.2 Public Private Partnerships (PPPs)

Over the past several years, public private partnerships have become an increasingly intriguing method of introducing new highway capacity when and where conditions are suitable for these innovative but sometimes controversial arrangements. While most PPPs have emerged in the context of traditional expressway projects, there are a number of PPPs either in place or planned in niche transportation markets involving Express Lanes and HOT lanes.

It is important to develop clear lines of responsibility for the PPP entity and the public entity, or DOT, especially in regard to operational and maintenance decisions on the HOT lanes or the general purpose lanes that have an operational impact on the other facility.

Figure 3-2: Benefits vs. Risks
+ Potential Benefits of PPP - PPP Areas of Potential Risks
  • An infusion of funds to the state associated with a long term lease or purchase of the toll road.
  • A reduction in the state costs to operate and maintain the road.
  • Potentially greater flexibility in setting toll rates and charges than a public entity has.
  • Potential cost and operational efficiencies if the toll road partner (operator) is operating other toll roads and has the resources and expertise to leverage this experience.
  • A loss of control of operations that could affect operations and roadway quality and the rates the customers pay to use the facility
  • Risk of revenue bond downgrading if the facility revenue bond financed and revenue or trip volumes are below what has been assumed in the financing.
  • Long term questions of financial viability of the roadway in the event of market changes, operator bankruptcies or changes in ownership.
  • Potential opportunity cost losses if toll revenues are greater than anticipated.

The decision to proceed with a PPP requires consensus at the highest levels in state government on program objectives, tolerance to financial risk and benefits to the public interest. States such as California have tested the PPP waters by authorizing the California Department of Transportation (Caltrans) to enter into franchise agreements with private companies to operate and maintain private toll roads. Other states struggling with traffic congestion have also investigated private toll roads as a means of addressing expanding roadway capacity through private toll roads.

3.3 Procurement Strategies

Once the concept of operations is defined and operational requirements are established, the sponsoring agency must develop a procurement strategy through which the components of the HOT lane system are acquired. Given the time frame required for most HOT lane procurements, this decision should be made no later than approximately two-and-a-half to three years prior to the planned live date for reasons described in more detail below.

3.4 Procurement Options

There are two major elements of the HOT lane system that will be procured: 1) roadway-related work, and 2) the electronic toll collection (ETC) system. For several important reasons, the two elements should not necessarily be procured using the same strategy:

  • Roadway Work. Improving the roadway involves civil work such as widening, paving and surfacing, gantry installation and electrical work, including power and communications to the ETC and variable message sign (VMS) equipment. Much of this work lends itself to competitive bidding on a low price basis from qualified bidders. There are two procurement options for roadway work:

    • Design-Bid-Build. Under this option, the sponsoring agency provides all of the roadway design detail and puts the package out for bid on a low bid basis.

    • Design-Build. Here, the sponsoring agency develops preliminary designs and then puts the package out for bid to a design-build team. (Note: this procurement option may lend itself to the RFP process discussed in the next bullet in order to facilitate an evaluation of the design/build team’s overall design capabilities and concepts).

  • ETC Systems Work. ETC work involves designing (including developing and integrating), installing and potentially maintaining and operating an ETC system, including software and communications to the lane equipment and critical back office operations. Because the ETC work is highly specialized, it does not lend itself to a selection solely on a low bid basis.

    A request for proposal (RFP) is the recommended approach to ensure that the selection of the system integrator considers all critical factors including technical solution, team qualifications and experience and price. As mentioned above, the scope of the ETC procurement can be limited to design and installation of the ETC system or it can cover all aspects of operations as well. There are three basic models to consider in the ETC system integrator procurement:

    • Design-Build. The System Integrator designs, builds and installs the system and then turns it over to the Sponsor, who then hires a separate entity to maintain the system (or use in-house resources). The Sponsor will also have to a separate agreement with a Customer Service Center (CSC) operator to process the transactions and bill customers and handle violations. The sponsoring agency can obtain these services through a separate RFP or can make an agreement with another agency to “piggyback” on their existing customer service center operations.

    • Design-Build-Maintain. Where the System Integrator not only designs, builds and installs the ETC system, but also maintains the system for fixed period of time, for example, five years. Here, the sponsoring agency would again have a separate agreement for CSC operations or could operate the CSC.

    • Design-Build-Operate-Maintain. The System Integrator is completely responsible for all aspects of HOT lane implementation and operations, including maintenance and CSC operations for an agreed to period of time.

      If the sponsoring agency does not have experience maintaining ETC systems, it is recommended that the Sponsor use a design-build-maintain RFP. Whether the sponsor agency also chooses to include CSC operations in the RFP depends on a number of factors such as the availability and cost effectiveness of using an existing CSC of another agency and the desire to separately procure CSC operations through a separate RFP.

3.4.1 Procurement Sequencing

The proper sequencing of roadway infrastructure and ETC procurements is critical to project success. Specifically, it is desirable to have the System Integrator in place prior to the completion of the roadway design package. This will enable the System Integrator to have input into the placement, type and number of ETC equipment gantries, communications infrastructure requirement, placement and types of equipment cabinets, and roadway issues related to any in-road ETC equipment. This will minimize change orders to both the roadway contract and the ETC contract. As the roadway improvements are constructed, the System Integrator can work with the Sponsoring Agency to complete the system design and development, which typically takes approximately 12 months.

3.5 Procurement, Implementation and Construction Issues

A prerequisite to initial and long-term success of a HOT lane implementation is proper management of all stages of project development (from procurement through construction and final testing). The project development process must be viewed as a unified process, with multiple interdependent links. Several key guidelines should be kept in mind while planning the ETC construction process:

  • A detailed design, implementation and construction schedule should be stated in the RFP. The schedule should be refined prior to notice-to-proceed (NTP) and updated regularly throughout the design and installation process. The schedule must also recognize all of the key design, testing and installation elements and consider coordination with roadway design and construction.

  • The RFP should require the System Integrator to prepare a transition plan. The transition plan, which will be refined in the design process, should clearly identify a timeline for the construction and transition of the HOV lanes to HOT lanes.

  • Construction planning, staging and project costs must accommodate maintenance and protection of traffic. Performing work on an existing roadway with live traffic operations is a major challenge, and plans to mitigate the impact of construction on parallel roadway operations must be developed.

  • The RFP should include rigorous performance standards for the installed equipment and the overall system. It is recommended that the RFP be developed as a performance-based document rather than an equipment specification. The RFP should specify rigorous performance standards, which place the burden of designing a system to meets those requirements squarely on the System Integrator.

  • Include sufficient time for testing in factory, on-site pre-live and live acceptance testing in the RFP. The system should not be considered complete until a live acceptance test for a period of 30 to 60 consecutive days verifies system operation.

3.6 HOT Lane System Design

Creating a toll facility within an existing highway requires attention to system design considerations, which must be evaluated on its potential impact within a corridor or region. A feasibility study assists in the developing support for the venture and provides the basis for developing a project design plan.

The design plan for the implementation of a specific HOV system conversion is generally developed from a corridor study that provides feasible alternatives for consideration. It most likely will be corridor-specific, or applicable to a network of lanes on several corridors, depending on the specified problem and demand characteristics. Regional consistency is desirable, and many areas (e.g. Los Angeles, Seattle, and Atlanta) have implemented systems where most facilities operate in the same manner and appear consistent to the user.

3.6.1 Geometric Requirements

HOT lanes may involve single or double lanes operated on a reversible-flow basis or one or two lanes providing continual service in each direction, or multiple lanes that can operate concurrently. An example of the latter is the planned SANDAG I-15 Managed Lanes which will comprise four lanes which can operate on a concurrent flow basis such as 2/2 or 3/1. However, in order to maintain premium traffic service levels and discourage toll violations, HOT lanes generally require access control along with effective enforcement. Additionally the physical configuration of HOT lanes and accesses to the HOT lanes should minimize excessive weaving between highway mainlines.


Barrier separation on 2-lane reversible I-15 Express LanesGuidelines from AASHTO, TxDOT, Caltrans and FHWA provide varying design standards for implementing managed lane facilities. For example, for total clear width for a single-lane barrier separated reversible lane, AASHTO advises 20-22 feet, TxDOT suggests 20-26 feet, Caltrans suggests 27 feet and FHWA recommends 20-32 feet for HOT lanes.[8] In the absence of HOT design standards, highway design standards and guidelines pertaining to HOV lanes are often applied to HOT lanes. Since express lanes are essentially HOT lanes with all traffic being tolled, these design standards are also compatible for implementing express lanes.



Table 3-1 provides the recommended cross-section standards for HOT lanes, or tolled managed lanes, as recommended by the FHWA.

Table 3-1: Managed Lane Cross-section Standards
Cross-section Element Standard
Lane Width
  • 12 feet, 3.6 meters
Shoulder Width (Right and Left)
  • 10 feet, 3.0 meters preferable 2 feet, 0.6 meters minimum (dependent on number of lanes, type of operation, sight distance).
Separation (Buffer) Width for non-barrier separated operation
  • 4 feet, 1.2 meters
Sight Distance
  • Standard stopping sight distance for facility type
Safety Considerations
  • Crash attenuation for exposed barrier ends
  • Transition treatments with HOV or general-purpose lanes
  • Adequate access opening lengths

As the national guidance for HOV facilities, AASHTO’s ranges establish the minimum values for state DOT’s. Development of Express Lane or HOT facilities by various DOTs are typically based on shoulder widths and controlling project parameters anticipated at the time project design guidelines were established.

Because right-of-way availability varies from one location to another there are various design standards to consider for separating HOT lane traffic from the general purpose lanes. In addition there may also be situations where deviations from recommended design standards may have to be considered because of additional corridor constraints. Geometrics for managed lane facilities can be divided into four general categories.[9]

Table 3-2 provides a summary of the physical design options that may be implemented and the benefits and issues that may be associated with each type.

Table 3-2: Operational Impacts of Physical Design Options
Physical Design Options Benefits Issues
Concrete Barrier
  • Reversible lane concept
  • Safety from general purpose lanes
  • Easier to enforce compliance
  • Users have feeling of confinement
  • No way out during accidents unless removable rail or gates are installed
Flexible Delineators (Pylons)
  • Inexpensive and achieves visible separation
  • Transition treatments with HOV or general-purpose lanes
  • Adequate access opening length
  • Frequent maintenance / replacement
  • Safety due to vehicles able to drive through delineators
  • Possible flying hazard when hit by vehicles at speed
Buffer Separated
  • Inexpensive
  • Vehicles have a way out
  • Easy removal
  • Easy to install
  • Safety due to vehicles cutting in and out
  • Extra right-of way requirements
Non-Buffer Separated (Pavement Markings)
  • Inexpensive
  • Vehicles have a way out
  • Easy removal
  • Easy to install
Safety and enforcement issues due to vehicles cutting in and out
Non-separated Shoulder
  • Provides extra capacity without having to add a lane
  • Confusion over lane use
  • Lack of emergency pull outs for disabled vehicles
  • May have to be rebuilt if transit buses are allowed to use.
Grade Separation
  • Exclusive use
  • Safest
  • No way out
  • Lengthy construction
  • Expensive
  • Users have a feeling of confinement
  • Easier enforcement


Access Control Strategies

Another key design consideration is the extent to which drivers have multiple opportunities downstream of the first HOT access point to buy-in to the HOT lane. The number of access points is linked to the corridor geometry, safety, facility revenue collection objectives and violation enforcement.

For example, in the case of the 91 Express Lanes, Riverside County officials perceived the 91 Express Lanes as a tube, with few opportunities to enter the facility westbound beyond the eastern access location. For MnPass, MnDOT identified multiple access strategies to accommodate their system configuration; very restricted access for the 3-mile reversible segment and multiple access point for the 8 mile concurrent flow segment. Besides safety considerations, separate pricing strategies were implemented to manage demand in each section.


Figure 3-3: Access Control Diagram for MnPass

Graphic. Figure 3-3. Access Control Diagram for MnPass.

Additionally, in developing the number and locations of exit and entry access points, consideration must be given to the tradeoff impacts of items such as the additional infrastructure, operating and violation enforcement, the cost of additional entry/exit points, and the attractiveness of additional entry and exit points for SOV, HOV, and transit (where applicable) users.

Electronic Toll Collection (ETC)

The technologies involved in electronic toll collection are all well-proven and in use on nearly every significant toll road, bridge, and tunnel in the country. Electronic toll collection systems generally rely on four major components: Automated Vehicle Identification, Automated Vehicle Classification, Violation Enforcement and Transaction Processing.

All of these systems are included in A Highway 407 ramp toll zone. However, depending on agency objectives, some implementations do not employ all four components. In this section, we will briefly introduce and discuss these components:

  • Automatic Vehicle Identification (AVI) System. An AVI system determines the identity of a vehicle traveling through either toll gates in a traditional barrier configuration toll plaza, or through an open road (high speed) tolling area. In either facility configuration the object is to correctly identify the vehicle in the tolling area and to apply the applicable toll charges to the correct account.

  • Photo. TransCore eGo Plus sticker RFID tag, mounted on the vehicle via Dedicated Short Range Communications (DSRC).

    Current AVI systems rely on radio frequency identification (RFID), where an antenna located above the roadway communicates with a transponder, similar to the TransCore eGo Plus Sticker Tag, also known as an RFID tag, and mounted on the vehicle via Dedicated Short Range Communications (DSRC). RFID tags have proven excellent accuracy, and can be read at highway speeds. All transponder tags currently in use by toll agencies in the United States operate at 915 MHz. While all of the AVI system providers in the US, operate in the 915 MHz band they are not all interoperable. Generally there is regional interoperability, where agencies in the region use the same transponder, antennas and associated protocols. Examples of this are CTOC (California), E-ZPass (Northeast and portions of the Midwest) and SunPass (Florida). There is some movement toward the use of multi-protocol readers, which could read more than one transponder type and protocol but this has not yet been implemented on any large scale.

  • Automatic Vehicle Classification (AVC) System. Vehicle classification determines the toll rate to be charged a vehicle using the HOT facility. It may also be used in combination with the AVI and VES technology to determine if a vehicle is violating vehicle access restrictions.

    Various sensors may be used to determine classification. Some agencies may opt to use a single type of classification sensor while other agencies may use more than one sensor type in order to eliminate classification errors or mismatches. The various sensors include:
    • Inductive sensors embedded in the road surface can determine the gaps between vehicles, to provide basic information on the presence of a vehicle and the approximate vehicle length.

    • Photo. Wavetronix Remote Traffic Microwave Sensor monitors traffic from the roadside.

      True Presence Microwave Radar can determine vehicle classification by length in a manner similar to the inductive sensors. Remote Traffic Microwave Sensor (RTMS) by Electronic Integrated Systems (EIS) and Smart-Sensor by Wavetronix are examples of this type of detector which monitor traffic from the roadside as shown.

    • Treadles permit counting the number of axles as a vehicle passes over them and, with offset-treadle installations, also can detect dual-tire vehicles.

    • Light-curtain laser profilers record the shape of the vehicle, which can help distinguish trucks and trailers. Active Infrared Detectors have the ability to classify vehicles by measuring and identifying their profiles. Some examples of Active Infrared Detectors are Autosense II and Autosense III by Schwartz Electro-Optics, Inc and the Laser Scanners by Sick, Inc.
  • Violation Enforcement System (VES). Enforcement is critical if a HOT lane facility is to be successful and effective. The enforcement strategy and the technology implemented must be reliable, highly visible and one that promotes fairness. Most facilities currently use visual (manual) enforcement together with some technical support to monitor HOT lanes. Although utilizing enforcement vehicles to stop apparent violators may not be the most efficient method to actually gain compliance with the managed lane restrictions it is the most visible to the public, including the public traveling in the general purpose lanes. This visible enforcement effort demonstrates that the agency or entity controlling the use of the managed lanes is serious about maintaining the integrity of use by vehicles qualified to be in the designated managed lanes.

    The technical support that often is used to supplement manual enforcement may consist of a gantry mounted violation indicator light to provide an indicator for near-by enforcement vehicles to act on. Additionally some facilities use video cameras together with optical character recognition (OCR) system to capture the license plate image of the vehicle as it passes through the toll zone. The camera may be mounted above the roadway or along side the roadway, depending on the geometry of the HOT facility and the violation objectives of the facility. Once the license plate image is captured it must be correctly ‘read’ by the OCR in order to successfully locate the vehicle owner to collect the toll and if applicable, the toll evasion fine.

  • Transaction Processing System. The transaction processing component, is commonly referred to as the ‘back office) of most systems. It also may be referred to as the "Customer Service Center" which in many respects, performs activities that resemble banking functions. Transaction Processing deals with maintaining customer accounts, posting toll transactions and customer payments to the accounts, handling customer inquiries and determination and processing of violations.

For transaction processing to be both accurate and effective requires a reliable communication network to transmit the ETC and/or image transaction information from the lane to the back office processing center. It is imperative that appropriate data collection and delivery techniques, as well as redundant and manual systems, are in place to guard against data loss or corruption particularly with any transactions, images, or operational information.

The transaction data transferred to the ‘back office’ for processing not only must be accurate, processed and reported in a timely and consistent manner to support a dynamic 24/7 operation, but must also be auditable. Of singular importance is the issue of security and integrity of all data collected by the toll collection system.

Supporting Systems

With ETC, there are several supporting systems that need to be integrated into the overall system architecture to ensure that the functional requirements of the system are met, and the customer interfaces with the system in a simple-to-understand and seamless manner.

  • Photo. Video camera mounted to overhead gantry.Closed Circuit Television (CCTV). The use of video CCTV cameras along the facility may be used to support general traffic surveillance, detect incidents within the HOT lane facility, confirm message accuracy displayed on VMS or variable toll message signs and provide supplemental image support for violation enforcement.

  • Variable Message Signs (VMS). VMS provide traveler information, traffic, construction or incident alerts, and travel time advantage comparison and costs for use of the HOT lane. A special application of VMS is the announcement of the toll in effect at the time of entry into the HOT facility. This specific application is referred to as a Variable Toll Message Sign (VTMS) and may either be implemented as a stand alone electronic VMS type of sign or it may be a hybrid combination with static information with a variable insert to provide either the toll rate or estimated travel times to some down stream locations.

Figure 3-4: MnPass Variable Message Sign

Photo. Figure 3-4. MnPass Variable Message Sign.

  • Digital Video Audit Systems (DVAS). DVAS provide an audit capability of transactions at a toll zone location. The systems provide a time based video record of activity in a given toll zone that ties an image to the transaction data generated by the system. The DVAS system provides remote access for both real time monitoring and file query to verify a transaction record. The transaction data record consisting of the location, time of day, lane (if more than one), vehicle classification and transponder ID is overlaid on the video record permitting fast and accurate assessment of any anomaly.

  • ITS Support Systems. ITS is being integrated with HOT system requirements to provide traveler information and for integration into regional traffic management systems. Some of the support systems that are being employed along HOT corridors include:
    • Photo. Variable Message Sign (VMS).511 Interface;
    • DMS signage for regional traffic information;
    • incident detection systems to assist in both facility and regional traffic management and control;
    • traffic monitoring devices for integration in the regional monitoring plan;
    • CCTV surveillance; and
    • highway advisory radio

HOV Enforcement

Accurately determining the number of occupants in a vehicle is difficult at best and often results in having an enforcement officer mistakenly stopping HOV vehicles because an occupant, such as a child, in addition to the driver, is not readily visible in the back seat. Enforcement of occupancy requirements is the most difficult operational challenge facing toll agencies and enforcement officers in HOT lane implementations because automatic technologies have not yet met reliability and field accuracy requirements required for operational deployment. In addition, there are a host of cost and privacy considerations associated with the technology.

Facility design also influences the types of enforcement needed. Barrier separation features act as a deterrent to potential violators, but require areas along the facility to monitor, apprehend and cite violators. Barrier separated facilities generally make apprehension fairly easy, since the violator is confined in the lanes after entering the facility; however, it should be noted that the larger the facility (i.e., number of lanes) and the larger the quantity of entry and exit points, the more difficult manual enforcement is.

Non-barrier separated HOT lanes are the most difficult to enforce, since it is easy to enter and exit the lane simply by changing lanes. Facilities that use delineators, such as the SR91, deter violators, but may still experience violators ‘diving’ through the delineators. Locations where delineators are used typically do not have adequate shoulder space for effective road side enforcement.

Some actions that can be taken to enhance the performance for HOV violation enforcement may include:

  • During the design phase have engineers meet with highway patrol officers to determine locations best suited (safe adequate space) for road side enforcement.

  • If there is adequate space lanes consider installing concrete barriers.

  • Prominently and with consistency post the fine for HOV/HOT violations on roadside signs.

  • Use random and prominently visual, special enforcement followed by routine enforcement.


[8] Toycen, C., (2006), "Tough To Be Single," TM+E, July, Vol. 11, No. 2. Back to reference 8.

[9] Caltrans High-Occupancy Vehicle Guidelines, 2003 Edition. Back to reference 9.

June 2007
Publication #FHWA-HOP-08-034