June 2007

Considerations for High Occupancy 

Vehicle (HOV) Lane to High Occupancy 

Toll (HOT) Lane Conversions Guidebook

U.S. Department of Transportation

Federal Highway Administration

Office of Operations 21st Century Operations Using 21st Century Technology

Considerations for High Occupancy Vehicle (HOV) to High 

Occupancy Toll (HOT) Lanes Conversions Guidebook

Prepared for the

HOV Pooled-Fund Study

and the

U.S. Department of Transportation

Federal Highway Administration

Prepared by

HNTB

Booz Allen Hamilton Inc.

8283 Greensboro Drive

McLean, VA 22102

Under contract to

Federal Highway Administration (FHWA)

June 2007
Notice

This document is disseminated under the sponsorship of the Department of Transportation in 

the interest of information exchange. The United States Government assumes no liability for its 

contents or the use thereof.

The contents of this Report reflect the views of the contractor, who is responsible for the accuracy of the data presented herein. The contents do not necessarily reflect the official policy of 

the Department of Transportation.

This Report does not constitute a standard, specification, or regulation.

The United States Government does not endorse products or manufacturers named herein. 

Trade or manufacturers’ names appear herein only because they are considered essential to 

the objective of this document.
Technical Report Documentation Page

1. Report No.

FHWA-HOP-08-034

2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle

Consideration for High Occupancy Vehicle (HOV) to High Occupancy Toll 

(HOT) Lanes Study 

5. Report Date

June 2007

6. Performing Organization Code

7. Author(s)

Martin Sas, HNTB.

Susan Carlson, HNTB

Eugene Kim, Ph.D., Booz Allen Hamilton Inc.

Michael Quant, Booz Allen Hamilton Inc.

8. Performing Organization Report No.

9. Performing Organization Name and Address

Booz Allen Hamilton Inc.

8283 Greensboro Drive

McLean, VA 22102

10. Work Unit No. (TRAIS)

11. Contract or Grant No.

12. Sponsoring Agency Name and Address

Federal Highway Administration

HOV Pooled-Fund Study

1200 New Jersey Avenue SE

Washington DC 20590

13. Type of Report and Period Covered

Research Report

14. Sponsoring Agency Code

15. Supplementary Notes

16. Abstract

 The intent of this study is to explore the planning, design, and ongoing operation and maintenance of HOT facilities 

and to provide lessons learned and applicable technical guidance that will assist the state and local transportation 

planners and designers in determining the conditions where HOV conversion to HOT lanes is feasible. The study 

reviewed a broad range of operational HOT facilities from having been operational many years to recently being 

opened. The study reviewed the activities of each in the planning, design, implementation and operations with special attention given to institutional, design, and operational challenges. 

The guidebook provides a summary of the best practices and lessons learned from those HOT facilities currently in 

operation. The result is “Best Practices Top 20” list that evolved as each of the facilities learned or re-learned what 

other HOT facilities had previously learned. The result was a re-occurring list of “to do”s and what “not to do” to 

minimize issues during the HOV to HOT transition process. 

17. Key Words

High-Occupancy Vehicle, HOV Lane, HOV

Enforcement, HOV Facility Enforcement, HOV Facility

Design, HOV Planning, HOV Operations, HOT Lane,

HOT Facility Enforcement

18. Distribution Statement

No restrictions. This document is available to the public 

through NTIS: National Technical Information Service

Springfield, Virginia 22161

www.ntis.gov

19. Security Classif. (of this report)

Unclassified.

20. Security Classif. (of this page)

Unclassified.

21. No. of Pages

76

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
SI* (Modern Metric) Conversion Factors

Approximate Conversions to SI Units Approximate Conversions from SI Units

Symbol When You Know Multiply By To Find Symbol Symbol When You Know Multiply By To Find Symbol

Length in inches 25.4 millimeters mm mm millimeters 0.039 inches in

ft feet 0.305 meters m m meters 3.28 feet ftyd yards 0.914 meters m m meters 1.09 yards ydmi miles 1.61 kilometers km km kilometers 0.621 miles mi

Area in2 square inches 645.2 square 

millimeters

mm2 mm2 square 

millimeters

0.0016 square inches in2

ft2 square feet 0.093 square meters m2 m2 square meters 10.764 square feet ft2yd2 square yards 0.836 square meters m2 m2 square meters 1.195 square yards yd2ac acres 0.405 hectares ha ha hectares 2.47 acres acmi2 square miles 2.59 square 

kilometers

km2 km2 square 

kilometers

0.386 square miles mi2

Volume fl oz fluid ounces 29.57 milliliters ml ml milliliters 0.034 fluid ounces fl oz

gal gallons 3.785 liters l l liters 0.264 gallons galft3 cubic feet 0.028 cubic meters m3 m3 cubic meters 35.71 cubic feet ft3yd3 cubic yards 0.765 cubic meters m3 m3 cubic meters 1.307 cubic yards yd3

Mass oz ounces 28.35 grams g g grams 0.035 ounces oz

lb pounds 0.454 kilograms kg kg kilograms 2.202 pounds lbT short tons (2,000 

lbs)

0.907 megagrams Mg Mg megagrams 1.103 short tons 

(2,000 lbs)

T

Temperature (Exact)

°F Fahrenheit 

temperature

5(F-32)/9or (F-32)/1.8

Celsius temperature

°C °C Celsius 

temperature

1.8 C + 32 Fahrenheit 

temperature

°F

Illumination fc foot-candles 10.76 lux lx lx lux 0.0929 foot-candles fc

fl foot-lamberts 3.426 candela/m2 cd/m2 cd/m2 candela/m2 0.2919 foot-lamberts fl

Force and Pressure or Stress

lbf pound-force 4.45 newtons N N newtons 0.225 pound-force lbfpsi pound-force

per square inch

6.89 kilopascals kPa kPa kilopascals 0.145 pound-force

per square inch

psi

* SI is the symbol for the International System of Units. Appropriate rounding should be done to comply with Section 4 of ASTM E380.

Metric Conversion Chart
Acknowledgements

This document was prepared by HNTB and Booz Allen Hamilton Inc. and received extensive comment from the HOV 

Pooled Fund Study (PFS) Group.

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Considerations for High Occupancy Vehicle (HOV) to 

High Occupancy Toll (HOT) Lane Conversions Guidebook

Table of Contents

Table of Contents

Chapter 1. Introduction and Overview .............................................................................................1-1

1.1. What are High Occupancy Toll (HOT) Lanes? ........................................................................1-2

1.1.1. HOT Lane Characteristics and Applications ...............................................................1-2

1.2. Purpose of the High Occupancy Toll Lane Guidebook ............................................................1-4

1.3. Study Approach/Methodology .............................................................................................1-5

Chapter 2. High Occupancy Toll (HOT) Policy and Planning..............................................................2-1

2.1. Baseline Performance Framework for High Occupancy Vehicle Lanes.....................................2-1

2.2. Understanding the Effects of Converting an HOV Lane to HOT Lane.......................................2-2

2.2.1. Shifts from HOV to LOV and from LOV to HOV ............................................................2-3

2.2.2. Shifts from other Routes and Times..........................................................................2-3

2.2.3. Second-order Effects and Long-Run Equilibrium .........................................................2-3

2.3. Key Planning and Policy Criteria...........................................................................................2-3

2.3.1. Legal and Institutional Challenges.............................................................................2-5

2.3.2. Building Support for HOT Lanes ................................................................................2-6

2.3.3. Application of Project Development Approach ............................................................2-7

2.3.4. Unique Project Risks/Challenges ..............................................................................2-8

2.4. Project Financing..............................................................................................................2-10

Chapter 3. HOT Lane Implementation & Design...............................................................................3-1

3.1. Organization and Management............................................................................................3-1

3.1.1. Participation ............................................................................................................3-1

3.1.2. Organization and Management Plan ..........................................................................3-2

3.2. Public Private Partnerships (PPPs).......................................................................................3-3

3.3. Procurement Strategies......................................................................................................3-3

3.4. Procurement Options..........................................................................................................3-4

3.4.1. Procurement Sequencing..........................................................................................3-5

3.5. Procurement, Implementation and Construction Issues ........................................................3-5

3.6. HOT Lane System Design .................................................................................................. 3-6

3.6.1. Geometric Requirements......................................................................................... 3-6

Chapter 4. HOT Lane Operations and Management..........................................................................4-1

4.1. Lane Management .............................................................................................................4-1

4.2. Toll Collection Operations ...................................................................................................4-2

4.2.1. Transponder and AVI Technology ...............................................................................4-3

4.2.2. Video Tolling............................................................................................................4-3

4.2.3. System Operations ..................................................................................................4-4

4.3. HOT Lane Enforcement.......................................................................................................4-5

4.3.1. Concept of Operations .............................................................................................4-5

4.3.2. Facility Design Considerations ................................................................................. 4-6

4.3.3. HOT Lane Enforcement Functions ............................................................................ 4-6

4.3.4. Recent Experience with HOT Lane Enforcement .........................................................4-8

4.3.5. Best Practices in HOT Lane Enforcement...................................................................4-9

4.4. Signage...........................................................................................................................4-10

4.5. Incident Management.......................................................................................................4-12

Chapter 5. Case Studies of HOT Lane Conversion Projects...............................................................5-1

5.1. Data Collection Approach ...................................................................................................5-1
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Table of Contents

5.2. Focused Interviews ............................................................................................................5-2

5.3. San Diego, CA I-15 Express Lanes ......................................................................................5-3

5.3.1. Project Objectives ....................................................................................................5-3

5.3.2. Concept of Operations .............................................................................................5-3

5.3.3. Innovative Project Features.......................................................................................5-3

5.3.4. Major Project Challenges/Mitigation Actions ..............................................................5-3

5.3.5. Major Lesson Learned............................................................................................. 5-4

5.3.6. Keys to Project Success.......................................................................................... 5-4

5.4. Minneapolis, MN I-394 Express Lanes................................................................................ 5-4

5.4.1. Project Objectives ................................................................................................... 5-4

5.4.2. Concept of Operations ............................................................................................ 5-4

5.4.3. Innovative Project Features.......................................................................................5-5

5.4.4. Major Project Challenges/Mitigation Actions ..............................................................5-5

5.4.5. Major Lesson Learned..............................................................................................5-5

5.4.6. Keys to Project Success ...........................................................................................5-5

5.5. Denver, CO I-25 Express Lanes .......................................................................................... 5-6

5.5.1. Project Objectives ................................................................................................... 5-6

5.5.2. Concept of Operations ............................................................................................ 5-6

5.5.3. Innovative Project Features...................................................................................... 5-6

5.5.4. Major Project Challenges/Mitigation Actions ............................................................. 5-6

5.5.5. Major Lesson Learned..............................................................................................5-7

5.5.6. Keys to Project Success...........................................................................................5-7

Chapter 6. Direction for Future Practice..........................................................................................6-1

6.1. Best Practices ...................................................................................................................6-1

6.1.1. Project Pre-Planning and System Planning .................................................................6-1

6.1.2. System Design ........................................................................................................6-1

6.1.3. Project Financing .....................................................................................................6-2

6.1.4. Implementation .......................................................................................................6-2

6.1.5. Operations and Management....................................................................................6-2

6.2. Lessons Learned ...............................................................................................................6-2

6.3. Direction for Future Practice................................................................................................6-3

6.3.1. Legislative...............................................................................................................6-3

6.3.2. Electronic and Video Toll Payment.............................................................................6-3

6.3.3. Enforcement............................................................................................................6-3

6.3.4. Occupancy Enforcement...........................................................................................6-3

Chapter 7. List of Acronyms............................................................................................................7-1

Chapter 8. References....................................................................................................................8-1
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High Occupancy Toll (HOT) Lane Conversions Guidebook

Table of Contents

Table of Tables

Table 3-1: Managed Lane Cross-section Standards ............................................................................3-7

Table 3-2: Operational Impacts of Physical Design Options .................................................................3-8

Table 4-1: Lane Management Control Strategies ................................................................................4-2

Table 5-1: Facility Characteristics......................................................................................................5-2

Table 5-2: Operational Characteristics...............................................................................................5-2

Table of Figures

Figure 2-1: Effects From Converting to HOT lanes ...............................................................................2-2

Figure 2-2: Public Outreach Model Used at MnPass............................................................................2-7

Figure 2-3: Sketch Development Approach.........................................................................................2-8

Figure 3-1: Stages of HOT Lane Project Development .........................................................................3-1

Figure 3-2: Benefits vs. Risks............................................................................................................3-3

Figure 3-3: Access Control Diagram for MnPass.................................................................................3-9

Figure 3-4: MnPass Variable Message Sign .....................................................................................3-12

Figure 4-1: Enforcement equipment used in MnPass ..........................................................................4-9

Figure 4-2: Sample HOT Signage.....................................................................................................4-11

Figure 4-3: Sample HOT Lane Signage.............................................................................................4-12

Figure 5-1: Location of Hot Lane Case Studies...................................................................................5-1
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1-1

Considerations for High Occupancy Vehicle (HOV) to 

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Chapter 1. Introduction

Chapter 1. Introduction and Overview

Traffic congestion on U.S. highways serving our largest metropolitan regions have reached unprecedented levels despite our heroic but, ultimately, failed efforts to build more highways in response 

to the nation’s insatiable demand for travel.1 With the benefit of several decades’ worth of hindsight, 

the U.S. transportation policy community has pledged a renewed commitment to attacking the 

urban transportation problem through a combination of demand and system management strategies 

focused on managing our existing transportation supply more effectively and efficiently. 

Some of these ideas have been around for as long as the automobile itself. A major cornerstone 

of transportation system management (TSM) is the High Occupancy Vehicle (HOV) lane, which was 

first popularized in the U.S. during World War II as part a national fuel rationing program. Highway 

agencies and toll authorities across the U.S. operate over 2,500 HOV lane miles, with approximately 

2,500 more HOV lane-miles planned over the next thirty years. 

The presence of HOV lanes is an important inducement for ridesharing, which reduces vehicle trips 

and, in turn, lowers traffic congestion. In addition, HOV lanes – by moving high occupancy vehicles – 

can carry more passengers per hour than general purpose highway lanes. Today, many HOV facilities 

do in fact outperform adjacent general purpose highway lanes in terms of person throughput, especially during peak hours of service. By themselves, however, the extent to which HOV lanes induce 

new ridesharing beyond pre-existing levels is debatable and varies from region to region. Trip chaining, particularly family-related trip movements, and other factors (e.g. the scarcity of potential carpool 

matches) may dis-incentivize new HOV formation regardless of the presence of viable HOV express 

options. When new carpool formation is low, HOV lanes may go underutilized and do not meet expectations about congestion relief benefits.

Over the past decade, the commercialization of new technologies has 

created new opportunities to manage 

highways using age-old economic principles. The application of these innovative concepts have demonstrated 

unequivocally that congested highways 

can be managed more effectively and 

expand user choices. These applications come in a variety of names – 

managed lanes, high occupancy toll 

(HOT) lanes, Express Lanes, and smart 

roads. Together, they represent a growing body of evidence suggesting that 

efficient and effective management of 

existing highway assets is both achievable and sustainable.

The primary purpose of this document is to provide technical guidance and recommended practices 

on an increasingly popular highway system enhancement opportunity: the conversion of HOV lanes 

to HOT lane. The guidebook is based on industry best practices with special consideration given to 

1 Small, K., C. Winston, J. Yan, March 16, 2006, “Differentiated Road Pricing, Express Lanes, and carpools: Exploiting 

Heterogeneous Preferences in Policy Design”

I-15 Express Lanes in San Diego, CA
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Considerations for High Occupancy Vehicle (HOV) to 

High Occupancy Toll (HOT) Lane Conversions Guidebook

Chapter 1. Introduction

applicable pricing techniques, planning, cost estimation and operational requirements, including the 

application of supporting Intelligent Transportation System (ITS) technologies.

1.1. What are High Occupancy Toll (HOT) Lanes?

The Federal Highway Administration (FHWA) defines managed 

lanes as highway facilities, or a set of lanes, in which operational strategies are implemented and managed (in real time) 

in response to changing conditions. Managed lanes are distinguished from other traditional forms of lane management strategies in that they are proactively implemented, managed, and 

may involve using more than one operational strategy.2

The HOT lanes concept is a managed lane that combines HOV 

with pricing strategies to improve facility operations. Unlike 

HOV lanes, HOT lanes allow single occupant vehicles (SOV) to 

gain access to HOT lanes if they choose to pay the applicable 

toll. To maintain the “improved facility operations” and the service benefits of a HOT lane, HOT lanes may employ some or all 

operational strategies.

1.1.1. HOT Lane Characteristics and Applications 

Although HOT lane operational and policy parameters may vary from facility to facility, they share several common characteristics with respect to system design, physical configuration, operations and 

technology. FHWA’s “Guide for HOT Lane Development” identifies several major characteristics of 

HOT lanes:

- HOT lanes typically are limited-access; normally barrier-separated highway lanes that 

provide free or reduced cost access to qualifying HOVs, and also provide access to other 

paying vehicles not meeting passenger occupancy requirements. (Note: The geometric 

limitations of the existing HOV facility are the 

primary reason HOV to HOT lane implementations are not barrier separated from the general purpose lanes. Instead striping or plastic 

delineators are generally used as a buffer.)

- By using price and occupancy restrictions to 

manage the number of vehicles traveling on 

them, HOT lanes maintain volumes consistent with uncongested levels of service even 

during peak travel periods.

- Most HOT lanes are created within existing general-purpose highway facilities and offer potential 

users the choice of using general-purpose lanes or paying for premium conditions on the HOT 

lanes.

2 “A Guide for HOT Lane Development”, U.S. Department of Transportation, Federal Highway Administration

Operational Strategies

- Restrict HOT lane ingress 

and egress to specifically 

designated and marked 

locations to / from the 

general purpose lanes 

- Limit vehicle eligibility

- Use a variable time-ofday pricing structure to 

manage demand and 

congestion.

Barrier – separate reversible flow facility
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Considerations for High Occupancy Vehicle (HOV) to 

High Occupancy Toll (HOT) Lane Conversions Guidebook

Chapter 1. Introduction

- HOT lanes utilize sophisticated electronic toll collection (ETC) and traffic information systems that 

also make variable, real-time toll pricing of non-HOV vehicles possible. Information on price levels 

and travel conditions is normally communicated to motorists via variable message signs (VMS), 

providing potential users with the facts they need in order to decide whether or not to utilize the 

HOT lanes or the parallel general-purpose lanes that may be congested during peak periods.

- HOT lanes may be created through new capacity construction, conversion of existing lanes, or 

converting HOV lanes to HOT lanes with additional capacity added. Since both right of way and 

construction funds are limited, conversion of existing HOV lanes to HOT operation is the most common approach.

Occupancy requirements on HOV facilities are usually set at HOV 2+. HOV 2+ lanes represent 

approximately 95 percent of all HOV lane miles operated in the United States. Nationally, most HOV 

lanes perform within the generally accepted range of peak performance:

- Of HOV lanes with the HOV 2+ eligibility requirement, approximately 70 percent of he nation’s HOV 

lane miles operate with peak hour volumes between 900 and 1,500 vehicles per hour.

- Of the remaining 30 percent, 10 to 15 percent of HOV vehicles are operating with over 1,500 peak 

hour vehicles, and the remaining 10 to 15 percent operate at or below 900 vehicles per hour in 

peak hours. 

Multi-lane HOV facilities that suffer chronic peak hour underutilization (below 900 vehicles per 

peak hour) comprise the pool of facilities most suitable for conversion to HOT lanes. HOV facilities 

that carry between 900 and 1,500 vehicles per peak hour generally do not offer sufficient residual 

capacity to sell to SOVs without risking lower level of service (LOS) than baseline peak conditions.3 

Experience has shown that raising minimum HOV access requirements to HOV+3 has had minimal 

effect on HOV lane performance since the number of HOV +3s is generally less than the number of 

HOV +2s that were using the HOV lanes. This condition may in fact result in underutilization of the 

HOV lanes. Additionally, with deflection of HOV +2s onto general purpose lanes, it is very likely that 

prevailing traffic congestion on general purpose lane will worsen. 

Capacity is also influenced by factors such as facility geometry, the number of access points and the 

number of travel lanes. Consequently, HOT lane capacity varies from location to location. For example, a single HOT lane will have a lower managed capacity than a HOT facility with multiple lanes. 

Volumes on the Houston I-10 Katy Freeway QuickRide – a one lane, reversible-flow facility are kept 

to 1,500 vehicles/hour. However, the 91 Express Lanes provide two managed travel lanes in each 

direction and have been able to operate at acceptable conditions with flow rates of 1,800 vehicles/

hour/lane.4 The 91 Express Lanes expands the toll zone in each direction to three lanes designating 

two lanes for HOT and one lane for HOV+3 use. HOV+3 are required to mount transponders in the 

vehicles and are charged a reduced toll rate.

HOT Lane Performance

The emergence of HOT lane pricing techniques has been facilitated by the use of ETC. These techniques can range from flat toll to dynamic by time-of-day and offer a wide range of options for achieving greater performance. Electronic pricing, when introduced in the appropriate operational context, 

has been shown to offer a cost effective strategy for creating and sustaining net travel time benefits. 

3 Ibid Chapter 6

4 Ibid Chapter 6
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Considerations for High Occupancy Vehicle (HOV) to 

High Occupancy Toll (HOT) Lane Conversions Guidebook

Chapter 1. Introduction

The case studies presented in Chapter 5 describe how different electronic pricing applications are 

used to maximize and maintain peak travel time savings. 

It is important to be able to evaluate the performance of the HOT lane facility against established 

measures of effectiveness, and estimate travel time benefits. In Chapter 2, a more detailed discussion of system performance and user benefits associated with HOT lanes is presented.

HOT Lane Benefits

HOT lanes are intended to provide a wide variety of 

benefits to multiple user groups. When applied in 

conjunction with other management tools and sensible, targeted provision of additional lane capacity, 

HOT lanes have the potential to generate significant 

improvements in congested travel corridors. 

HOT lanes can also afford a wide range of secondary benefits, including:

- New revenues that can be used to support the 

construction of the HOT lanes themselves or 

other initiatives, such as improved transit service 

or regional transportation initiatives; 

- Traffic service improvements on congested parallel highway mainline lanes by drawing vehicles off 

parallel local streets and improving corridor-wide mobility; 

- Performance reliability compared with general purpose lane during peak periods.

- Faster highway trips for express transit services such as bus rapid transit (BRT); 

- Environmental advantages by providing opportunities to encourage carpooling, improve transit service, and move more people in fewer vehicles at faster speeds;

- Increased efficiency of managed lane facilities making them attractive in regions that might not 

otherwise consider them; and, 

- Improving the utilization of HOV lanes and therefore eliminating potential pressure to convert under 

performing HOV lanes to general-purpose use. 

1.2. Purpose of the High Occupancy Toll Lane Guidebook

The intended audience of this document includes states’ departments of transportation (DOTs), 

Metropolitan Planning Organizations (MPOs), policy-making agencies, enforcement agencies and 

others having a role in the planning, development, management, operations, monitoring, evaluation 

and reporting on the performance of HOV and HOT lanes. The objective of the guidebook, which 

explores the planning, design, implementation and ongoing operations and maintenance of HOT lane 

facilities converted from existing HOV lanes, is to provide:

1. Technical guidance that will assist the state and local transportation planners in determining the 

conditions where conversion from HOV to HOT lanes is feasible and advisable, and 

The Primary Benefits of HOT Lanes

- They provide the driving public with 

a choice – premium and predictable 

travel conditions – on corridors where 

conditions would otherwise be congested, and 

- They maximize the use of managed 

lanes – including HOV lanes – without 

causing traffic service to fall below 

desired levels.
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Considerations for High Occupancy Vehicle (HOV) to 

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Chapter 1. Introduction

2. a comprehensive list of activities to be performed in the planning, implementation and operation 

of an HOT lane facility. Special attention is paid to institutional, system design and operational 

challenges that typically present themselves in the course of a conversion to HOT lane. 

Three case studies of HOT implementations are provided in the guidebook to further illuminate key 

practical insights and lessons learned that would be of value to HOT planners. The case studies are 

based on information gathered from on-site visits and a focused interview methodology. Focused 

interviews were conducted with key managers at three HOT lane projects: 

1. MnDOT’s MnPass I-394 HOT lanes, 

2. SANDAG I-15 Express and HOT lanes, and 

3. CDOT’s I-25 Express Lanes. 

1.3. Study Approach/Methodology

The approach and methodology used in developing the Guidebook included:

- Establishing a project development framework that advances the HOT conversion project from concept to implementation; 

- Employing a combination of formal interviews with recognized industry experts and selected agencies with experience in the implementation of both managed and HOT lanes;

- Conducting on-site focused interviews that inform three “case studies” of functioning HOT lanes; 

and, 

- Conducting a literature review of current industry practices.

The research and case studies focused on all elements of project implementation, including items 

such as planning, design, pricing strategies, construction, operational requirements, and the integration of ITS with the HOT lane application.
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Chapter 1. Introduction

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Chapter 2. High Occupancy Toll (HOT) 

Policy and Planning

Chapter 2. High Occupancy Toll (HOT) Policy and 

Planning

2.1. Baseline Performance Framework for High Occupancy Vehicle Lanes

Minimum occupancy requirements for the HOV lanes 

should be set to avoid both underutilization and overcrowding of the HOV lanes. The primary benefit of 

adding an HOV lane is that total highway capacity is 

increased, causing preexisting HOVs to divert onto the 

new HOV lane and allowing Single Occupant Vehicle 

(SOVs) to share highway mainlines with fewer vehicles. 

After this initial shift in lane utilization, the resulting 

travel time differential between the HOV lane and highway mainline lanes could induce secondary shifts (second order changes) from SOV to HOV up to the point 

where service levels in the HOV lanes are impacted. 

Research on HOV lanes (Dahlgren 1995) suggests that 

approximately 20 percent of the existing vehicles on a 

three-lane highway must be HOVs for an HOV lane addition to be effective and still offer enough of a travel time 

savings incentive to induce ridesharing. If enough travelers shift from SOV to HOV, congestion on HOV lanes can 

erode the travel time differential, thereby dampening the 

incentive needed to promote further shifts to HOV in the 

long term. In cases where the pre-existing HOV share is high, HOV lanes can suffer from periodic 

traffic congestion during the busiest times of day. Ultimately, HOV priority treatment may contain a 

self-limiting threshold both in very high congestion and no congestion conditions beyond which there 

are limited incentives to rideshare. 

HOV lane performance studies typically collect peak vehicle and passenger counts for HOV lanes and 

highway mainline lanes and obtain average travel speed and travel time data. HOV lanes can average three to 20 times the person movement of highway mainline lanes during peak hours. If HOV 

lanes that carry more peak passengers than comparable highway mainline lanes and maintain peak 

hour volumes between 800 – 1,000 vehicles per lane per hour are determined to be an effective system management strategy.

Many HOV lanes throughout the country, under existing HOV priority allowances, achieve performance 

consistent with those outlined in FHWA HOV Lane Performance Guidelines. The remainder of HOV 

lanes currently in operation suffers from mild to severe underutilization or overcrowding or both, 

depending of prevailing traffic conditions. It is this subset of HOV facilities that represent the pool of 

potentially feasible HOT conversion projects.

High Occupancy Vehicle (HOV) 

Lanes Are Intended To Meet

Three Basic Objectives

1. Provide a cost-effective means 

of moving greater volumes of 

persons at higher levels of service than mainline highway lanes 

by reserving dedicated lanes for 

multi-person vehicles; 

2. Promote ridesharing by setting 

aside reserved HOV lanes and 

offering travel time savings and 

reliability; and,

3. Reduce trip times of HOVs during congested times of day
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Considerations for High Occupancy Vehicle (HOV) to 

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Chapter 2. High Occupancy Toll (HOT) 

Policy and Planning

2.2. Understanding the Effects of Converting an HOV Lane to HOT Lane

The conversion of an HOV lane to HOT lane results in both 

operational and behavioral shifts. These shifts must produce a combined positive net benefit to users in order for 

the conversion from HOV lane to HOT lane to be deemed 

worthwhile. The purpose of this section is to describe the 

possible behavioral effects resulting from the conversion 

of an HOV lane to HOT lane that should be considering in 

evaluating and planning. 

As discussed above, the primary operational effect caused 

by the conversion to HOT lane is that Low Occupancy 

Vehicles (LOVs)5 who now pay to use the HOT lane will gain 

travel time savings. Converting an HOV lane to HOT results 

in overall delay reduction for LOVs both for those remaining 

in the highway mainline lanes and those that buy into the 

HOT lane. Pricing optimization techniques enable the HOT 

lane operator to maximize travel time savings differential 

between HOT lane and highway mainline lanes through the 

day. The ability to achieve and sustain travel time savings 

is generally considered one of the most important operational differences between HOV lanes and HOT lanes. 

Figure 2-1 provides a diagrammatic overview of the various effects of converting an existing HOV lane 

to HOT lane. 

Figure 2-1: Effects From Converting to HOT lanes

5 Low Occupancy Vehicles (LOVs) are defined here as vehicles that do not meet the HOV exemption and would be 

subject to the HOT lane toll

Convert HOV lane to HOT

Induce increased travel demand

Generate revenue

Reduce resources available for other actions

Improve peak performance

Induce simultaneous shifts from HOV to SOV & from SOV to HOV 

Reduce emissions

Reduce person-delay

Cost recovery

Reduce SOV delay

The reduction in travel

delay effect for LOVs is

manifested in two ways:

- LOVs diverting onto the HOT 

lane derive a travel time 

savings benefit, which they 

gain in exchange for a toll 

payment.

- The initial diversion of LOVs 

onto the HOT lane causes a 

reduction in traffic volumes 

and traffic density, as LOVs 

on the highway mainline 

lanes share capacity with 

fewer vehicles.
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2.2.1. Shifts from HOV to LOV and from LOV to HOV

After an existing HOV lane is converted to HOT lane, the LOV toll buy-in feature will induce some additional shifts from HOV to LOV. Before the HOV lane was converted to HOT lane, all motorists who 

could be induced to shift to HOV presumably had already done so. Converting the HOV lane to HOT 

lane is unlikely to increase or even maintain existing levels of rider sharing. HOVs that are made better off by disbanding the HOV in favor of paying for HOT lane service as an LOV will shift from HOV to 

LOV. Likewise, some travelers will disband HOVs simply because the diversion of LOVs onto the HOT 

lane will cause enough highway mainline delay reduction to make HOV travel no longer worthwhile.

2.2.2. Shifts from other Routes and Times

The travel time reduction on highway mainline lanes and the presence of a HOT lane will induce some 

secondary behavioral shifts:

- From alternative routes to the subject highway

- From off-peak to peak, which is not less congested

With reduced delay on highway mainline lanes, LOVs that had that had previously shifted to alternative routes to save time will return to the highway via mainline lane use or HOT lane. With reduced 

delay on the highway, both HOVs and LOVs that had previously shifted to alternative routes to save 

time will return to the highway. Both groups are better off.

2.2.3. Second-order Effects and Long-Run Equilibrium

The marginal shifts from other times of day and routes, coupled with additional trips stimulated by 

the reduction in peak highway delay, will gradually result in increases in highway volumes, thereby 

offsetting some of the delay reductions caused by opening HOT lane service to toll-paying LOVs. Patterns will evolve toward a long-term equilibrium in which the relative costs and benefits of HOT lanes 

and highway mainline lanes are no longer sufficient to motivate further shifts from HOV to LOV. Patterns will also be stabilized to the point where additional shifts to and from other times and routes 

are no longer induced.

2.3. Key Planning and Policy 

Criteria

The purpose of this section is to describe 

the HOT lane project screening criteria, 

and identify opportunities where HOT 

lanes may be the most effective means 

of addressing a critical mobility need. 

As discussed in Chapter 1, HOV lanes 

can be classified in terms of their average 

peak hour performance. HOV lanes that 

experience chronic underutilization (below 

700 vehicles per lane per peak hour) 

generally comprise the pool of potential 

candidates’ conversions to HOT lane. In 

these cases, the presence of an optimal 

toll set to maintain a minimum operating standard on the HOT lane will divert 

Pre-Planning Issues/Challenges

- How should HOV exemptions be modified to 

accommodate SOV toll buy-ins?

- What should the minimum operating standard for 

HOT lanes be?

- To what extent should access (ingress/egress) 

be limited to segregate traffic and preserve LOS 

performance goals on the HOT lane?

- How much are system implementation and ongoing operating costs for HOT lanes?

- What are the trade-offs between implementing a 

HOT lane and a toll lane with no HOV exemption?

- What legislative barriers need to be removed in 

order to convert an HOV lane to HOT lane?

- How should toll revenues be used?

- Who should own and operate the HOT lane?
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LOVs onto the HOT lane. Underutilized HOV lanes are considered the best candidates for conversion 

because : a) no additional lane capacity needs to be added to the existing operating envelope, and 

b) the minimum vehicle occupancy requirement does not have to be adjusted. 

HOV lanes that experience chronic peak hour congestion also reflect a mismatch between existing 

travel demand and lane capacity, and merit some type of policy treatment to address recurring operational shortcomings. However, all congested HOV lanes are not necessarily appropriate candidates 

for conversion to HOT lanes. In cases where there is potential excess lane capacity and there is no 

operational justification for adding a second HOV lane to an existing one-lane HOV facility, conversion 

to a two-lane HOT facility may achieve optimal operational conditions that cannot be duplicated by a 

two-lane HOV lane facility.6 (In other words, LOVs can occupy some of the otherwise under-utilized 

lane capacity).

Based on considerations such as those described above, the planning process should address a 

number of questions to determine how effectively a potential HOT conversion project addresses a 

current unmet transportation need. These include:

- Is there sufficient excess peak capacity to allow SOV toll buy-ins on an existing HOV lane without the 

need to expand lane capacity? The feasibility of a potential conversion project depends in large part 

to the amount of excess capacity that can be sold to SOVs. If there is abundant excess capacity on 

the existing HOV lane and traffic congestion on highway mainlines is moderate, it may be feasible to 

attract just enough SOVs onto the HOT lane through optimally priced dynamic tolling without necessitating any change in HOV toll exemption policies. In Chapter 6 Case Studies, further discussion is 

devoted to factors that result in a change in HOV toll exemption policies in place. 

- If there isn’t enough excess peak capacity in the existing HOV lane(s) to allow for SOV tolling, is 

there additional capacity that can be added to the existing HOV facility as part of an HOT conversion project? Many HOV lanes are only one-lane facilities with either limited or no barrier separation from highway mainline lanes. In cases where the potential market for premium HOT-lane 

service is large and mainline lanes suffer from severe to extreme peak congestion, it may be necessary to: 1) change the HOV exemption from HOV 2+ to HOV3+ or higher, 2) add a second HOT 

lane, or 3) do both. 

- If changing the HOV exemption from HOV-2+ to HOV-3+ or 

higher is necessary, will it result in behavioral shifts that 

undermine the mobility improvement objective? The existing HOV eligibility status in the HOV exemption policy should 

be preserved in the HOT lane context whenever possible. In 

many instances, however, preserving the current HOV exemption may not free up enough capacity to auction to LOVs 

willing to pay a toll for premium HOT lane service. If the 

exemption is increased from HOV-2 to HOV-3+, the magnitude 

of HOV-2s that disband may offset any increases in carpooling motivated by the presence of tolling. Should the ultimate effect be a net reduction in HOVs and a net increase in LOVs, this may 

undermine one of the key objectives underlying the HOT lane concept, which is to promote trip 

reduction corridor-wide. 

6 FHWA, A Guide for HOT Lane Development, page 7. 

SAFETEA-LU provides operating agencies with the flexibility to allow certain vehicles 

not meeting the occupancy 

requirements, including 

tolled single-occupant or 

lower-occupant vehicles. 
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- Are there any unique operational and physical characteristics of the existing HOV lane facility that 

will require major reconfiguration? Not every HOV lane, under its current operating configuration 

can be readily converted to HOT without some significant physical improvements to the existing 

facility envelope. In addition improvements to the to limiting ingress and egress into the HOT 

facility, it may be necessary to modify lane configurations both at the entry and exit points of the 

HOT facility to minimize queuing behind bottleneck locations. The facility may also have to accommodate additional equipment including location of variable toll message signs (VTMS) and electronic toll collection equipment and supporting gantries and cabinets, and maintenance areas and 

enforcement envelopes. 

2.3.1. Legal and Institutional Challenges

While there is growing interest in HOT lanes among local, state and federal transportation officials, 

there remain significant legislative and institutional barriers to widespread HOT lane implementation. 

Prior to the enactment of Safe, Accountable, Flexible, and Efficient Transportation Equity Act: A Legacy 

for Users (SAFETEA-LU), states were expressly prohibited from converting federal-aid highways and 

Interstates into toll facilities.

However, that policy was modified under SAFETEA-LU Pub. L. 109-59, August 10, 2005 to allow 

States and qualifying transportation agencies to use Federal funds for toll facility applications. Congress enabled three new exceptions, and modified one existing exception, to Title 23 of the United 

States Code, Section 301, which otherwise generally prohibits the imposition of tolls on facilities that 

use Federal funds. 

Through the applicable program States and qualifying transportation agencies may, with the execution of a toll agreement under Section 129 (a)(3), use Federal-aid funds for either the construction 

of or improvements to a toll facility or to the approach to a toll facility; or, for the reconstruction or 

conversion of a free highway, bridge or tunnel previously constructed with Federal-aid funds to a toll 

facility thus enabling conversion of HOV lanes to HOT lanes.

Specifically related to the conversion of HOV to HOT lanes, Section 1121 of SAFETEA-LU replaces 

Section 102(a) of Title 23 of the United States Code (23 U.S.C.) with a new Section 166 that clarifies some aspects of the operation of HOV facilities and provides more exceptions to the vehicle 

occupancy requirements for HOV facilities. It also authorizes states to create HOT lanes and allows 

states to charge tolls to vehicles that do not meet the established occupancy requirements to use 

an HOV lane if the state establishes a program that addresses the selection of certified vehicles and 

procedures for enforcing the restrictions. Tolls under this section may be charged on both Interstate 

and non-Interstate facilities. There is no limit on the number of projects or the number of states that 

can participate.
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2.3.2. Building Support for HOT Lanes

Perhaps the biggest barrier to wider HOT lane 

implementation is public opposition. Recent 

experience demonstrates that HOT conversion projects are feasible from an operational 

and technological standpoint. With the mainstreaming of HOT lanes on the state and 

federal level, the public become increasingly 

familiar with the HOT lane concept, and the 

benefits these facilities offer in terms of congestion relief. Today, they are not as controversial as they once were. However, HOT lane 

conversion projects – because they include a 

tolling component – often raise spirited opposition based on equity and fairness concerns. 

Yet HOT lanes still provide access for HOV 

users as well as providing both HOV and nonHOV users with an option, or another travel 

choice. 

With the increased federal support for tolling 

initiatives, states and metropolitan regions 

throughout the country have looked closely 

at their highway assets for opportunities to 

improve mobility via facility-specific electronic tolling or ‘smart road’ applications. In states like 

California, Texas, Utah, Minnesota, Colorado and Washington, HOT lanes have been folded into 

statewide and regional transportation management plans that place increasing emphasis on system 

management objectives. 

Over the past decade, public acceptance of electronic tolling applications on urban highways has 

increased, with the maturation of landmark projects like the 91 Express Lanes in Orange County, CA 

and the I-15 Express Lanes in San Diego, CA. Today, these facilities are commonly accepted by the 

public as critical elements of the region’s transportation system.

A common thread in every successful HOT conversion project is the execution of a coordinated effort 

to convey the justification for and benefits of the project and address public concerns about the 

implementation and ongoing operation of the project. It is important to note that the success of an 

HOT lane implementation should be measured by public acceptance as well as the ability to provide 

added capacity, and potentially additional revenues to support enhanced maintenance support and 

regional mobility objective. Public consensus for the planned project requires strong public involvement program throughout the life of the project, especially from the early planning stages. 

Public Outreach Strategies

Project sponsors that manage inclusive, responsive and effective outreach to stakeholders establish 

their own legitimacy and the legitimacy of the technical analyses, decision-making, and public processes that support project implementation.7 Establishing transportation taskforces and technical 

committees consisting of business, community members, and elected officials is a proven key to 

7 Perez, B.G., and G. Sciara. “A Guide for HOT LANE DEVELOPMENT”, Federal Highway Administration Report FHWAOP-03-009, Washington, DC, 2003

Key Stakeholder Outreach Actions

- Anticipate opposition early.

- Arrange focus groups to determine local 

issues and strategic opportunities to 

address specific concerns.

- Develop program objectives that address 

and mitigate social equity concerns.

- Gain consensus from key influential civic 

and community gatekeepers. 

- Enlist advocacy from a respected local official who will serve as project champion. 

- Manage expectations by establishing reasonable and achievable project objectives. 

- Deliver the project on-time and on-budget. 
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Policy and Planning

successful implementation for managed lane projects. For example, the QuickRide Program in Houston over individuals participated in 14 public meetings which helped bring forward issues such as 

access points and directional flow. In addition, having a strong public champion is a critical element 

in lending credibility to the outreach process and influencing key decision makers who may initially 

oppose HOT conversion projects without a clear understanding of potential project mitigations. 

Figure 2-2: Public Outreach Model Used at MnPass

SANDAG as well as MnDOT (MnPass) began public outreach programs very early in the project planning. SANDAG conducted stakeholder interviews, established a program of continuing surveys with 

both stakeholder and the public and held numerous public forums through implementation. MnPass 

created a local taskforce, the I-394 Express Lane Community Taskforce, at the outset of the program 

to address issues, desires, and design options. In addition they also held continuing public forums 

to keep the public informed and to address relative issues. 

2.3.3. Application of Project Development Approach

Figure 2-2 provides an overview of the multiple phases involved in the project development of the 

conversion of an HOV lane to HOT lane. Following an initial assessment of conversion feasibility and 

the decision to investigate the HOT lane conversion further, the conceptual framework for the HOT 

lane project is then developed and refined. The conceptual refinement stage evaluates various system design alternatives, and eventually recommends a preferred alternative. 

DISCOVERY

Focus Groups, Stakeholder Ascertainment, Traffic and Revenue Forecast,

Marketing Plan, Message Development

Chart provided by Frank Wilson Associates and Tanaka Advertising, PowerPoint presentation 

MnPass I-394 Express Lane Marketing Outline, October 28, 2004.

AWARENESS

Community Outreach, Cornerstone Media Events, Media Briefings

INTEREST AND EDUCATION

MnDOT/MnPASS Web Page, Press Tours,

B-Roll, Community and Media Briefings

INQUIRY

Advertising, Customer Service Center Web 

Site, Toll Free Number, Mail Back Application

PURCHASE 

MnPASS

POSITIVE

WORD OF

MOUTH
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Figure 2-3: Sketch Development Approach

The third phase identified in Figure 2-3 – Program & System Design – focuses on clarifying the 

design, operational and technological elements of the HOT lane conversion project. The fourth 

phase of the project involves developing the operational requirements of the system. The project 

sponsor, most likely the state DOT, will complete detailed engineering and design studies for the 

recommended alternative and develop the design specifications for the HOT lane project. The fifth 

phase involves the preparation of procurement documents for the construction of the HOT lane project and the selection of a contractor through a competitive solicitation process.

2.3.4. Unique Project Risks/Challenges

While there are a significant number of technical, policy and public issues that provide both risks and 

challenges for the successful implementation, the success of an HOT implementation is the ability 

to meet stated program goals. These goals must have community support early on in the planning 

process, and the development of the project must be consistent with the public’s expectations. In 

addition to public acceptance, there are a number of other critical hurdles that must be addressed in 

a successful implementation.

A risk mitigation plan is an important element of a successful HOT Lanes project. Risks should be 

outlined as a part of the alternatives analysis described above and used for evaluation of alternatives. Then, as the project moves through design and construction a risk management plan should 

be developed and periodically updated. The plan should identify all risks associated with the project, the degree of impact should the risk occur and the likelihood of that risk occurring. Examples of 

categories of these risks are schedule, technology, operating, public acceptance and environmental. 

Within these categories numerous sub-categories specific to the project can be identified and therefore mitigated.

All HOT implementations must address the following areas to minimize potential areas of risk:

Initial Project Assessment

Conceptual Refinement

Program & System Design

Procurement

Construction

Operations

Public

Outreach

Public

Coordination

Operational Requirements
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- Strong Interagency Support – Creating a strong public campaign that explains intended benefits 

and outcomes is critical to advancing a HOT conversion project from the earliest planning through 

project construction implementation to promote understanding and support for the project. There 

must also be: 

– Strong support from local, regional and state transportation officials and State Legislature,

– Strong Project Champion – Having a dynamic and respected public official publicly support and 

advance HOT lanes is critical to winning public support and can often accelerate the public outreach timeline. 

– Strong support from the Metropolitan Planning Organization (MPO), with HOT lanes identified in 

Regional Transportation Planning documents,

– Strong local sponsor, typically a regional transportation agency with highway management and 

operations responsibilities.

- Defining Program Objectives – HOT conversion projects must identify program objectives clearly 

from the outset, because the program objectives influence both project financing and potential for 

public/private partnership (PPPs). The program objectives should be realistic and defensible.

- Traffic Forecasting – It is critical that traffic forecasts are rigorous and conservative in testing the 

program alternatives, as these projections serve as input into potential revenue bonding and other 

project financing mechanisms. 

- Capital and Operating Cost Forecasting – It is also critical that estimates for the initial capital 

costs and ongoing operating costs are conservative and realistic, as these factors in combination 

with traffic forecasting, will determine the basic economic viability of the project.

- Project Financing – Some HOT conversion projects will be financed entirely with state and local 

funds, with some federal matching support. Others may be viable as investor-owned utilities 

underwritten by private investment. The financing arrangement may present risks to both the public and investors if project rates of return are lower than expected, and debt cannot be adequately 

serviced.

- Procurement – There are both financial and schedule risks associated with traditional versus more 

innovative procurement strategies; development of solid ETC system specifications and selection 

of a vendor (system integrator) is critical to the success of the project.

- Achieving Operational Goals – The HOT lanes can only be successful if they provide consistent 

and reliable Level-of-Service (although some degradation in LOS may occur from time to time). If 

the customer doesn’t get value (i.e. travel time savings) commensurate with the toll charge, then 

public trust in the HOT lanes will erode and the system will fail. 

- Establishing the Right Operating Model – It is critical that operating framework for the HOT 

conversion project reflect the program objectives. As further described in our case studies, (see 

MnPass) the operation and pricing strategies must be feasible, reasonable, and compatible with 

the program objectives.

- System Design Consideration – Creating a toll facility within an existing highway requires attention 

to all system design considerations including facility operations. Desired operational characteristics must be considered during both the planning and design phase of implementation so that 
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the facility design is operationally functional. Where possible design should be flexible to allow 

for changes in operational policies. Modes of operation such as two-way flow, reversible flow and 

contra-flow, incident management and allowed vehicle types allowed affect the geometric configuration. In addition to the operational considerations that impact design consideration other design 

considerations are listed in Section 2.4.

2.4. Project Financing

Substantial resources are required to plan, design, construct, operate and manage a HOT facility. 

The method of financing selected for a given HOT lane conversion project can involve both public 

and/or private funding sources. Based on recent experience, HOT project financing typically rely on 

traditional sources of public funds (e.g., fuel tax revenues), with some opportunities to leverage federal grant support. In a few unique cases, HOT lane conversion projects may be suitable for some 

form of revenue bonding or the sale of a private concession to construct, operate and maintain the 

facility. This section describes how HOT program goals influence both the method of project financing and, ultimately, the operating model chosen for the HOT lane.

Project funds for transportation capital expansion and facility upgrades are traditionally allocated by 

state DOTs or other local agencies according to the goals of long-range plans and the availability of 

programmable funds. Because HOT lanes generate revenues, however, they need not necessarily rely 

on allocation of total project funding through the traditional planning and programming processes. 

Instead, agencies can take advantage of innovative financing mechanisms such as revenue bonding 

and private concessions in order to accelerate HOT conversion projects. 

Revenue bonding for HOT lanes is similar to revenue bonding for other tolled transportation facilities. 

Under revenue bonding, a government agency issues bonds backed by future facility-generated revenues. Although revenue bonds typically carry higher interest rates than municipal bonds (which are 

guaranteed by more stable general tax revenues), they allow agencies to generate the capital necessary to implement projects quickly. Once the project is completed, the HOT lane revenues are, at 

least in part, dedicated to fulfilling obligations to the bondholders.

A second potential project financing mechanism is private concessions. Under the private concession 

model, a transportation agency leases the HOV facility to a private operator, sometimes in exchange 

for an up-front fee. The private operator is then responsible for any or all of the planning, design, 

construction, and operation aspects of the HOT conversion project. This arrangement makes most sense when 

the private operator is granted a contract to operate the 

facility and collect revenues for some fixed time frame, 

such as 30 or 50 years, beyond project completion. 

Benefits to the transportation agency include a transfer 

of project responsibility and risk as well as outsourcing 

of project activities (e.g., design and construction) to the 

private concessionaire. The concessionaire, on the other 

hand, must produce financial resources to complete the 

project, but is compensated by keeping a share of the 

revenues generated by the HOT facility once it opens.

On the other hand, revenue bonding may be sufficient to 

generate the capital necessary to complete the project 

in a reasonable and expedient time frame, in which case 

a private concession may not be desirable.

Selling Concessions

The advantages of private concession arrangements and revenue 

bonding depend on the particular 

situation and the goals ultimately 

set by the transportation agency. 

Private concessionaires can access 

both debt and equity stakeholders 

to finance the conversion project, 

which may increase the capital 

available for the project, thereby 

accelerating its completion, lowering 

construction costs, and generating 

revenues from the facility sooner.
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Regardless of the arrangement for financing the conversion project, HOT lanes will generate revenues, which accrue to either the operating agency or to the private concessionaire. In almost all 

cases, some proportion of the revenues generated will be dedicated to operating the HOT facility. 

Operations costs include lane management, toll collection and administration, enforcement, service 

patrols and incident management, basic infrastructure maintenance, back-office support, and perhaps facility depreciation (these activities are discussed in Chapter 4). Under a private concession 

or revenue bonding financial arrangement, the next obligation for generated revenues is to the debt 

and/or equity investors. Finally, once the obligations to all stakeholders are fulfilled, there is reasonable expectation that the operating agency or concessionaire may generate excess revenues from 

the HOT lane operation.

The allocation of excess revenues, should they materialize, depends on the goals and objectives 

determined by the operating agency prior to project initiation. Revenues can be dedicated for 

improvements to the HOT facility itself, applied to the entire HOT corridor, or distributed regionally to 

other corridors and/or other travel modes such as mass transit. In some instances, agencies may 

even determine appropriate uses outside of the transportation arena. 

Regardless of whether excess revenues materialize, the success of HOT conversion hinges on the 

ability of any particular project to meet two requirements. First, revenues should support the maintenance and operation of the HOT facility. Secondly, revenues should be sufficient to meet financial 

obligations to project investors. Consequently, accurate project cost estimates and realistic revenue 

forecasts are essential to the financial success of a conversion project.
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Chapter 3. HOT Lane 

Implementation & Design

Chapter 3. HOT Lane Implementation & 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

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).

System/Sketch 

Planning

■ Feasibility 

Assessment

■ Project Champion

■ Stakeholder 

Support

■ Develop Conceptual 

Framework

■ Legislative Action

■ Public Outreach

HOT Lane 

Implementation 

and Design

■ Define Objectives

■ Ensure Stakeholder 

Understanding

■ Clarify Design

■ Engineering and 

Design Studies

■ Develop Engineers 

Cost Estimate

■ Develop 

Specification

■ Public Outreach

Procurement

■ Determine Method

■ Prepare 

Procurement 

Document

■ Competitive 

Selection Process

■ Continued 

Champion Support

Final Design and 

Construction

■ Technology

■ Toll Rate Concept

■ Separation Type

■ Ingress / Egress

■ Signage

■ Toll Zone Location

■ Construction and 

Test

■ Public Information

Operations and 

Management

■ Hours of Operation

■ HOV Use / Fee

■ 24/7 Maintenance

■ Account 

Management

■ Enforcement

■ Violation Noticing

■ Stakeholder and 

Champion Support

■ Public Information
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- 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. 
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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. 

+ 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.

Figure 3-2: Benefits vs. Risks

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.
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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 
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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.
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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. 

Guidelines 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. 

8 Toycen, C., (2006), “Tough To Be Single,” TM+E, July, Vol. 11, No. 2

Design Considerations

- Signage (fixed and variable message), 

both on the HOT lanes and at ingress and 

egress locations

- Placement of Ingress and egress locations,

- Placement of visual enforcement and equipment maintenance areas

- Type of violation enforcement 

- Placement of electronic tolling equipment 

gantries and utilities,

- Incorporating the proper toll system equipment design on the lane and back office 

sides,

- Buffering and facility separation 

Barrier separation on 2-lane reversible I-15 Express Lanes
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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.

9 Caltrans High-Occupancy Vehicle Guidelines, 2003 Edition

Geometrics for managed

lane facilities can be divided

into four general categories

- Barrier Separated

- Buffer Separated

- Contiguous

- Grade Separated
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Table 3-2: Operational Impacts of Physical Design Options

Physical Design Options

Concrete Barrier

Benefits:

- Reversible lane concept

- Safety from general purpose lanes

- Easier to enforce compliance

Issues:

- Users have feeling of confinement

- No way out during accidents unless removable rail or gates are installed

Flexible Delineators (Pylons)

Benefits:

- Inexpensive and achieves visible separation

- Easy removal

- Have a way out

Issues:

- Frequent maintenance / replacement

- Safety due to vehicles able to drive through 

delineators

- Possible flying hazard when hit by vehicles at 

speed

Buffer Separated

Benefits:

- Inexpensive

- Vehicles have a way out

- Easy removal

- Easy to install

Issues:

- Safety due to vehicles cutting in and out

- Extra right-of way requirements

Non-Buffer Separated (Pavement Markings)

Benefits:

- Inexpensive

- Vehicles have a way out

- Easy removal

- Easy to install

Issues:

- Safety and enforcement issues due to vehicles 

cutting in and out

Non-separated Shoulder

Benefits:

- Provides extra capacity without having to 

add a lane

Issues:

- 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

Benefits:

- Exclusive use

- Safest

Issues:

- 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 
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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. 

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.

Figure 3-3: Access Control Diagram for MnPass

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.

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 

TransCore eGo Plus sticker tag
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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. 

– 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 

The MnPass Solution

MnPass has supplemented the 

violation indicator light by adding 

a portable transponder reader 

in the enforcement vehicles 

enabling enforcement officers 

to validate operational transponders while driving along side of 

or immediately behind a target 

vehicle.

Remote Traffic Microwave

Sensor (RTMS)
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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.

- 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 

Video camera mounted to overhead gantry
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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

- 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:

– 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 

Variable Message Sign (VMS)
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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.

The MnPass Approach

MnPass uses a solid double 

white line to separate HOT lanes 

from general use lanes. 

Dotted stripped line indicated 

authorized access / exit points. 

According to MnDOT, after lane 

stripping implemented, the 

violation rate has dropped from 

>20 % to less than 10%. 

Most drivers observe the double 

and stripped markings. Violators 

of marked stripping are fined 

$165.00 per occurrence.
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Chapter 4. HOT Lane Operations and Management

Vehicle movements between highway mainline lanes and HOT lanes must be managed carefully, with 

well-designed ingress and egress to avoid unnecessary bottlenecking, violation and unsafe weaving. 

Special attention to enforcement techniques, particularly with respect to verification of vehicle occupancy, is necessary to regulate demand and maintain facility integrity. 

Effective lane or facility geometry is a critical prerequisite to achieving LOS design and safety goals. 

Another important function is the ability to capture and identify user data for automatic billing. This 

requires an integrated system of in-lane devices with back office support that not only provides 

account management, customer service support and violations processing but also ITS support functions such as 511, advanced traveler information and incident management. The purpose of this 

chapter is to describe the basic element of effective HOT lane operations and management. 

4.1. Lane Management

When converting to a HOT lane within a larger highway network, consideration must be given to 

weighing appropriate balance between eligibility, level of service and pricing conditions in order to 

achieve effective and sustainable lane management. Determining peak hour volumes in highway 

mainline lanes and HOT lanes and establishing the minimum desired LOS in the HOT lane is the initial step in establishing a lane management process. The lane management system must establish 

LOS performance objectives and determine the maximum allowable peak hour volumes to achieve those 

objectives. The HOT lane pricing conditions function as a tool to manage traffic flow against the LOS 

performance objectives.

Without effective lane use management, there is a risk that the commodity being sold to the public 

– i.e. time savings over highway mainline lanes – will be greatly compromised. HOT lane traffic levels 

should be limited to volumes that provide reliable speed advantages over adjacent highway general 

purpose lanes. There are two critical issues that affect lane management:10

- Determining the HOT lane capacity for paying vehicles before congestion occurs; and

- Understanding the types of lane management strategies that can be applied to regulate demand.

HOT lane capacity is a function of the number of access points, the vehicle mix, roadway slope and 

configuration, separation treatments, and the number of travel lanes, among other variables. HOT 

lanes with fewer access points have higher lane capacity with those with more access points. Likewise, a multilane HOT facility will have a higher managed capacity (vehicles per lane per hour) than 

a single HOT lane configuration. For example, flows on the Houston I-10 Katy Freeway QuickRide – a 

one lane, reversible-flow facility are kept to 1,500 vehicles per lane per hour.11 In contrast, the 91 

Express Lanes – which provide two travel lanes in each direction – operate at acceptable conditions 

with flow rates of 1,800 vehicles lane per hour.

On an unpriced highway, increasing volumes result in decreased speed. When the volumes reach 

an unstable point, speeds to drop to around 15-20 miles per hour. With this reduction in speed, 

lane capacity will drop from 2,000 to 2,100 vehicles per lane per hour to about 1,300 vehicles per 

lane per hour.12 In order to maintain “free flow” conditions in HOT lane facility, vehicle throughput is 

10 “A Guide for HOT Lane Development”, U.S. Department of Transportation, Federal Highway Administration

11 Ibid, Chapter 6

12 Ibid, Chapter 6
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regulated through variable pricing to a level below maximum capacity. This volume threshold serves 

as the benchmark for ensuring premium level of service for HOT lane users.

Table 4-1: Lane Management Control Strategies

Tool Operational Impact

Occupancy Limiting lane use to vehicles carrying a minimum number of passengers. HOV 2 

and HOV 3 are typical occupancy constraints, however there can be variations 

on this theme if the managed lane facility is an express lane project where every 

vehicle pays a fee with vehicles carrying more than one occupant receiving a discount (similar to SR-91 HOV3+ discount).

Eligibility Limiting lane use to specific types of users, such as two axle vehicles only, 

motorcycles, low emission vehicles, or trucks.

Access Limiting the number of access points or using ramp metering for lane access so 

that demand cannot overwhelm the managed lane capacity.

Pricing

(Variable, Fixed, 

or Dynamic)

Imposing a user fee that help regulate demand by time of day or day of week. 

The fee increases during expected periods of highest demand if time-of day pricing is employed or the fee increases dynamically as demand increases.

In summary, lane management strategies to regulate traffic flow on HOT lanes include:

- Eligibility,

- Vehicle Occupancy,

- Access,

- Toll Rate (variable or fixed), 

- Type of variable pricing (dynamic based on travel value, time of day, etc.)

The impact of each lane management tool is briefly presented in the adjacent table. Applied in combination, these tools offer the flexibility needed to maintain strong LOS on the HOT lanes. An appropriate range for HOT lane capacity in most project settings would be approximately 1,600 to 1,800 

hourly automobile equivalents per lane.

4.2. Toll Collection Operations

Toll collection systems may consist of conventional cash lanes, dedicated electronic toll collection 

lanes or Open Road Tolling (ORT). If at all possible, toll collection must have a seamless customer 

interface and, equally importantly, have no negative impact on traffic flow. ETC is used on nearly 

every significant toll road, bridge, and tunnel in the country. These technologies are well-proven and 

provide the type of seamless customer interface and transaction reliability that make them critical to 

HOT lane operations. The technologies used for electronic toll collection and pursuit of toll violators 

consist of Automated Vehicle Identification and Transponder Technology, Automated Vehicle Classification Video Image Capture and Account Processing and Customer Service. The electronic toll 

collection technologies for capturing tolls automatically is generally referred to as ETC (with a transponder) and Video Tolling (no transponder).
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4.2.1. Transponder and AVI Technology

Most current AVI systems rely on Radio Frequency Identification (RFID) technology, which enables communication with a 

transponder affixed to a vehicle via Dedicated Short Range 

Communications (DSRC). A transponder is an RFID device 

that, when mounted on a vehicle’s windshield, enables the 

electronic collection of highway tolls by an AVI system as it 

passes through the toll zone. The ‘reading’ of the transponder may occur while the vehicle is traveling at stop and go 

or highway speeds. The AVI system typically consists of an 

antenna and reader installed above a toll lane to automatically “read” or identify the transponder, and the vehicle 

associated with it.

ORT and HOT lane implementation requires that tolling occur at highway speeds up to 100 mph. The 

difference between an HOT and an ORT implementation is the toll zone for an HOT implementation is 

lane based, generally one or two lanes, while in an ORT implementation a toll zone consists of multiple lanes. With both ORT and HOT implementations, there are no physical toll plazas, but the factors 

that determine gantry locations and how tolls are assessed are no different than those which determine conventional toll plaza locations. The features observed by the driver are the toll gantry (basically a highway sign structure) with the electronic toll collection equipment on it, the related support 

infrastructure, and toll signage to tell drivers that they are passing a payment point and how much is 

being charged. The technologies used in both implementations are basically the same. 

Users who have established an automatic toll account are provided a transponder to install in their 

vehicle. The data written to the transponder at the time an account is established typically include 

information on vehicle classification, special group discounts, or special authorizations for a given 

vehicle type. When passing through a toll zone, the transponder data is compared with the in-lane 

monitoring systems to validate vehicle classification, special discounts or special authorizations that 

transponder and vehicle combination for a given account. Once proper account authorization has 

been verified, the applicable toll is then charged to the account and automatically deducted from a 

pre-paid account balance.

If the information on the tag and vehicle data do not correspond with a valid account, or if for some 

reason there is insufficient funds available in an account, or if the vehicle does not have a transponder, or has an improperly mounted transponder, the vehicle will be treated as a violator. 

For many HOT lanes, SOV users are required to have a transponder while HOVs are exempted. 

Recent studies, however, have shown that requiring transponders on all vehicles improves enforcement through the use of visual indicators and/or video image capture of license plates. Requiring 

transponders in all vehicles, HOV, SOV, and transit, provides for easier identification of SOV and HOV 

vehicles or violators without a transponder, and for quick and easy implementation of special discount program rates at the back office and not in the lane.

4.2.2. Video Tolling

Video tolling generally makes use of the open road toll enforcement cameras and the computer systems that support image and license capture, character recognition, and user location or citation 

processing. Video tolling allows the occasional user, tourist, or rental car motorist to establish a 

valid toll account either prior to using an ORT lane, or within a specified time after completing their 

trip. The time after trip completion is typically on the order of up to 72 hours. Generally a video toll 

Vehicle Transponder used in 91 Express Lanes
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account may be established by phone or WEB based interface with the motorist providing a credit or 

debit card number, vehicle license plate, make, model and type of vehicle. 

Video toll accounts, using valid vehicle license plate numbers, are downloaded to the toll zone or 

lane controller and the video controller in the lane in accordance with procedures established by 

the facility’s Business Rules. If the motorist does not have either a valid transponder or valid video 

account the captured image is retained to be processes as a violation transaction. 

The violation will be subjected to an image review process to determine if the license plate belongs 

to either a transponder customer or video toll account. If verified to be a valid license plate account 

the ‘violation image’ is converted to a toll transaction using the video image review and posted to the 

customer account.

The implementation of video toll systems in the lane use one or two video cameras with supplemental lighting to capture either the rear of the vehicle centered on the license plate area or two cameras 

to capture an image of both the rear and front of the vehicle. In facilities that restrict vehicle traffic to 

cars or two axle vehicles a single camera is sufficient to capture the rear of the vehicle and satisfactorily obtain an unobstructed and readable license plate image. For facilities that permit towed vehicles or semi-trailers, it is recommended that both front and read image capture cameras be used to 

ensure an unobstructed capture the truck’s front license plate and possibly the license plate of the 

towed trailer. It is essential that a front image capture be utilized for facilities with high truck and/

or semi-trailer traffic since the rear license plate of the truck will normally be blocked by the towed 

trailer.

Image capture systems with camera and supplemental lighting may be mounted either overhead 

or along the side of the toll lane(s). The majority of image capture implementations use pulsed or 

flashed, high intensity LED white lighting since it is best suited to handling multiple colored license 

plate characters and backgrounds, and infrared lighting for license plate character capture in a black 

and white image. However, there are some implementations that measure ambient lighting and supplement with continuous lighting as needed to successfully perform optical character recognition on 

the captured image. 

The millisecond flashes for pulsed and strobe lighting that are only triggered when an apparent violation (includes Vtolls) has occurred, or is detected must be unnoticeable by the user. Cameras 

mounted overhead with continuous white lighting is likely to cause visual impairment to the driver and 

should not be deployed for front license plates capture. Flashed/pulsed, strobe and infrared lighting 

solutions should be considered to avoid impairing the driver’s vision.

4.2.3. System Operations

In order to ensure reliable system operations, the HOT lane facility must include operational 

resources to provide maintenance, customer service, and account management.

- Maintenance. Since HOT lane systems employ totally automated electronic toll collection equipments, it is critical to the seamless use of the system by customers and to maintain revenue 

collection capability to employ 24/7 maintenance of the system. To minimize down time and to 

facilitate maintenance actions, it is critical that a maintenance on line monitoring (MOM) system 

is included with the HOT ETC system. Monitoring of all toll zone collection equipment status for 

failures or malfunctions that could impact the collection of revenue will minimize down time and 

revenue losses. 
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- Customer Account Service Center. Customers should have easy access to account information 

via a variety of means including web-based, telephone and mail and should be able manage their 

accounts with the tools provided. The Service Center must provide customer support and handle 

customer problems and complaints promptly handle customer problems and complaints; it must 

maintain ongoing communication with the public as well as stakeholders; and provide ongoing outreach information to provide the latest information on the HOT lanes operations and status.

- Video Processing Center. As video tolling becomes more widespread together with video image 

capture of violators the Account Service Center may well develop into dual purpose Customer 

Service and Video Processing Center (CSC/VPC) that not only establishes and manages transponder and Video Toll accounts, but also ensure that true violations are processed and funds are 

recouped.

4.3. HOT Lane Enforcement

Enforcement is critical to the successful operation of any HOT lane facility. An effective HOT lane 

enforcement program should ensure that operating requirements, including enforcement of tollexemption eligibility based on vehicle occupancy, are maintained to preserve travel time savings, discourage unauthorized vehicles, and maintain a safe operating environment. 

This section reviews HOT lane operational concepts and identifies unique issues and challenges 

associated with HOT lane enforcement. Enforcement strategies used in several HOT lanes similar in 

scale and length to the projects reviewed in this study are discussed. 

4.3.1. Concept of Operations

HOT lanes are toll facilities that charge a toll to all HOT lane users except for vehicles that meet the 

minimum occupancy for toll-exemption eligibility. In order to deter violations and reserve capacity for 

users, the HOT lane operator must be able to identify violators who use the HOT lane without paying. 

In addition, the HOT lane operator must be able to distinguish between vehicles required to pay the 

toll and HOVs that are eligible for toll-exemption.

Most HOT lanes today that utilize electronic toll collection require users to establish a pre-paid 

account from which toll transactions are debited for HOT trips taken. The requirement for users to 

have an active HOT lane account provides a partial solution for toll lane enforcement. Because all 

vehicles are required to have an active HOT lane account, motorists entering the HOT lane without a 

valid account are, by definition, considered in violation of the usage policy. Image capture technology 

is very reliable and can be utilized to read and capture license plate information. With this information, HOT lane operators can issue violation citations, collect tolls owed, and process fees. 

The technology used for violation enforcement is similar to Video Tolling for image capture and 

license plate reading. All images of the license plates of suspected violators are sent to the VPC, 

the interface to the CSC for toll violation processing. The CSC contains infrastructure equipment, 

software and services to process violations and license plate read images. Once the VPC has 

confirmed that the captured license plate is not linked with a valid transponder, the VPC will link to 

associated VPC and/or DMV databases to obtain the identity and address of the vehicle’s registered 

owner, prepare billing for notification to the violator, and, if required, pursue that individual for reimbursement of tolls, fees, and penalties.

The enforcement system must be able to recognize HOVs that meet the minimum occupancy requirement and exempt them from the toll. In addition, the system must be able to distinguish toll-exempt 
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HOVs from violators. Can this be accomplished without requiring all vehicles to establish a pre-paid 

account, including vehicles that will use the HOT lane primarily as toll-exempt HOVs? Based on the 

experience of recent HOT lane projects, the answer is no. Given the current state of technology, 

it is not possible to distinguish a violator from an eligible HOV from among the population of nontransponder equipped vehicles. Consequently, most HOT lane operators have chosen to require all 

vehicles, including toll-exempt HOVs, to establish active accounts with the HOT lane.

For HOT lanes that offer toll-exemption for eligible HOVs, the task of enforcement remains a major 

operational challenge. Why? Because there is currently no technology available that allows a HOT 

lane operator to assess a differential toll or provide a toll exemption based on observed vehicle 

occupancy. As a result, determination of vehicle occupancy has to be performed manually through 

visual inspection either at a fixed post or in transit. Another important wrinkle – given the operator’s 

inability to determine vehicle occupancy prior to a vehicle entering the HOT lane – is that the burden 

of realizing the HOV toll exemption is on the driver, not the HOT lane operator. In other words, the 

driver of the toll-exempt HOV must de-activate the transponder to prevent the HOT lane operator from 

inappropriately charging the toll. This in turn requires the enforcement system to be able to verify 

occupancy for HOVs that might otherwise be confused for a violator. 

4.3.2. Facility Design Considerations

Facility design is also an important element of HOT lane enforcement. Barrier separation features 

can be effective in deterring potential violators, but barrier separated systems also require additional 

space along the facility to monitor, apprehend, and cite violators. Barrier separated facilities generally make apprehension fairly easy, since the violator is confined within the lanes after entry; 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 becomes.

Non-barrier separated HOT lanes are more difficult to enforce, since it is easy to enter and exit the 

lane simply by changing lanes. Lane delineators such as those in use on the 91 Express Lanes in 

California can deter violators, with some instances of 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 state highway patrol officials to determine 

locations best suited (safe, adequate space) for road side enforcement.

- If there is adequate space, consider installing concrete barriers.

- Prominently post the fine for HOV/HOT violations on roadside signs.

- Use random visual, special enforcement followed by routine enforcement.

4.3.3. HOT Lane Enforcement Functions

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 catching violators, 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.
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Enforcement of HOT lane usage must accomplish the following key operational functions: 

- Verify toll payment (or credit)

- Verify vehicle occupancy

- Assess fine to violators.

Verify Toll Payment

Most current AVI systems rely on RFID technology, which enables communication with a transponder 

affixed to a vehicle via Dedicated Short Range Communications. A transponder is an RFID device 

that, when mounted on a vehicle’s windshield, enables the HOT lane operator to collect an electronic 

toll as it passes underneath the toll zone. 

The ‘reading’ of the transponder may occur while the vehicle is traveling at stop and go or highway 

speeds. The AVI system typically consists of an antenna and reader installed above a toll lane to 

automatically “read” or identify the transponder, and the vehicle associated with it.

Verify Vehicle Occupancy

As stated earlier, accurately determining the number of vehicle occupants poses a tremendous challenge. When volumes rise, it is difficult to catch all violators, let alone distinguish violators from eligible HOVs. From time to time, an enforcement officer mistakenly stops HOVs because an occupant 

in addition to the driver (e.g. small child) is not readily visible in the back seat. Enforcement of occupancy requirements is perhaps the most difficult operational challenge facing toll agencies; this is 

because automated technologies have not yet met reliability and field accuracy requirements needed 

for operational deployment. In addition, there are a host of cost and privacy considerations associated with the use of such detection technology.

The technical support used to supplement manual enforcement typically consists of a gantrymounted violation indicator light to provide an indicator for near-by enforcement vehicles to act on. 

Additionally, some facilities use video cameras together with an 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.

Assess Fine to Violators

Violations fall within two classes: a) enforceable (no transponder read, but license plate read; vehicle 

not linked to an active account), and b) Unenforceable (no transponder read and no license plate 

read). An effective HOT enforcement program should attempt to keep violations (enforceable and 

unenforceable) to at or below 10% of total trips.

HOT lanes typically require the creation of local ordinances that carefully document the process for 

resolving violations. The ordinance should establish a multi-stage notification process, in addition to 

establishing fine notification procedures that are consistent with the Georgia vehicle code. A multistage notification process with a graduated fine structure is typically used to provide differential penalties for first-time violators versus habitual offenders. 

In California, for example, the 91 Express Lanes uses the following graduated violation structure:

- Notice of Toll Evasion (NTEV) – $20 

- Notice of Delinquent Toll Evasion (NDTEV) – $55
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- Notice of Toll Violation Assignment – $80 

- Other Collections – per Georgia vehicle code penalties

The Orange County Transportation Authority (OCTA) reports that of the total number of enforceable 

violations, 60% are dismissed with no penalty, 11% pay toll + penalty and 20% go to collections. In 

total, 80% of all enforceable violations are addressed at the NTEV/NDTEV stage. 

4.3.4. Recent Experience with HOT Lane Enforcement

I-15 Express Lanes (San Diego, CA)

The I-15 Express Lanes is a barrier-separated, reversible flow HOT lane that has recently expanded 

from an 8-mile facility (with two toll zones) to a 20-mile facility with multiple access points. Because 

of the limited roadway geometry and restricted shoulders, shoulder enforcement on the extended 

segment is a major challenge. The mode of enforcement will require more mobile enforcement capabilities, with use of supporting reader technologies in mobile units. 

The San Diego Association of Governments (SANDAG) contracts with the California Highway Patrol 

(CHP) to perform manual enforcement at designated enforcement areas. Under this contract, CHP 

periodically supplements the fixed post visual enforcement with mobile enforcement units. SANDAG 

reports enforcement remains one of the biggest challenges facing the day-to-day operations of the 

I-15 Express Lanes, especially given the opportunities to violate the facility along the extended segment. I-15 Express Lanes violation rates range between 5% and 15%, with some time-of-day and 

seasonal variations. 

91 Express Lanes (Orange County, CA)

On the 91 Express Lanes, visual enforcement is performed at three locations where the median was 

widened to accommodate a vehicle. Flexible delineators separate the Express Lanes from the SR-91 

mainline lanes, with no intermediate access locations between the eastern and western entry points 

of the facility. The entry points have a dedicated HOV3+ lane and an Express Lane. Only eligible 

HOV3+ vehicles can enter the HOV3+ lane; these vehicles are charged a half-toll. 

The Orange County Transportation Authority (OCTA) contracts for enforcement with the California 

Highway Patrol (CHP), which performs visual enforcement at three locations along the 91 Express 

Lanes. OCTA reports that the violation rate for the 91 Express Lanes is approximately 8%. 

MnPass (Minneapolis, MN)

MnPass uses a solid double white line to separate HOT lanes from general use lanes. A dotted 

striped line indicates authorized access / exit points. According to MnDOT, after lane striping was 

implemented, there was a drop in the violation rate from over 20% to less than 10%. Violators of 

marked striping are fined $165.00 per occurrence. 

The enforcement strategy, which was considered critical to the success of the MnPass program, 

combines visual enforcement with mobile reader technology. It is worth noting that there was very 

little enforcement of the I-394 HOV lane prior to conversion to MnPass, with violation rates between 

20-30%. With the opening of MnPass, enforcement was carried out through a partnership with the 

Minneapolis Highway Patrol, Minneapolis Police Department, and Golden Valley Police Department. 

Combined, the enforcement contracts cost approximately $165,000 annually. 

Enforcement of valid trips is accomplished through three methods:
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- Enforcement tags – special transponders in police vehicles that register an audible tone if a valid 

transponder is read.

- Mobile reader – this device is mounted on police vehicles and can provide information on last valid 

reads.

- Enforcement beacons – stationary flashing light that flashes when a valid transponder is read at 

the access point.

Figure 4-1: Enforcement equipment used in MnPass

MnPass has supplemented the violation indicator light by adding a portable transponder reader in 

the enforcement vehicles enabling enforcement officers to validate operational transponders while 

driving along side of or immediately behind a target vehicle.

SR-167 HOT Lanes (Seattle, WA) 

SR-167 uses an electronic toll collection system that features an in-vehicle transponder, over-roadway transponder readers mounted on overhead gantries, and variable message signs that post the 

time-of-day toll. Similar to MnPass, SR-167 uses a solid double white line buffer to separate the HOT 

lane from adjacent highway mainline lanes. 

When a vehicle passes through the access point with an active transponder, a flashing enforcement 

light activates. If the light does not flash, state highway patrol checks to see if the vehicle has two 

or more occupants. If not, the vehicle is cited with a violation. 

4.3.5. Best Practices in HOT Lane Enforcement

The successful operation of a HOT lane facility is dependent upon a visible and effective enforcement program that the public perceives as fair and consistent. For the time being, the ability to deter 

violations and abuses of the HOV exemption allowance is strongly tied to the visibility of HOT lane 

enforcement presence. When lane enforcement presence is weak or non-existent, violation rates 

can rise above the generally accepted range of between 8-15%. 
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The enforcement strategies used HOT by lane operators provide some useful insights on best practices and lessons learned. Below is a summary of key findings:

- All users should be required to have a valid account for the HOT lane, regardless of vehicle occupancy status.

- Establishing contracts with state highway patrol and local law enforcement is the most effective 

and practical means of monitoring vehicle occupancy.

- Providing enforcement vehicles with mobile transponder readers helps law enforcement with verification of valid transactions. 

- Barrier-separation of the HOT lane from mainline lanes is more effective in deterring in-and-outweaving and opportunistic violations.

- Allowing HOVs to turn off transponders is an effective but flawed way (since it relies on the driver 

taking an action that they forget to take) to allow HOVs to self-provide the toll exemption.

- Space along a widened median should be provided at strategically located enforcement zones, 

where law enforcement can visually inspect vehicle occupancy from a fixed location. 

- The other method of allowing HOVs to receive a toll exemption or discounted toll, is to set aside a 

separate HOV entry lane that segregates HOVs from toll-paying SOVs. 

- Having a strong enforcement presence is a key to deterring violations and maintaining the integrity 

of HOT lane operations. 

- The following table provides a summary of enforcement strategies, their complexity, and 

effectiveness.

4.4. Signage

Accurate, informative signs are essential in explaining operational procedures of HOT lane facilities 

and ensuring safe access and egress from the managed lanes. HOT signs should provide motorists 

with information on:13

- Access and egress location

- Occupancy requirements

- Operating hours

- Toll rates

- Enforcement

A major element in HOT operations and management is signage, both upstream and downstream of 

the facility’s ingress/egress points. Inadequate signage can diminish the customer’s ability to make 

an informed travel decision and may compromise vehicle safety. Often there are possible conflicts 

between signing for general purpose lanes and for managed lanes. Drivers in both lane types can 

see not only a message intended for their lane use but can also see the message for the other lanes 

as well. The signage needs to be such that each driver clearly understands which message should 

be followed. 

13 Perez, B.G., and G. Sciara. “A Guide for HOT LANE DEVELOPMENT”, Federal Highway Administration Report FHWAOP-03-009, Washington, DC, 2003
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Coordination of signage both from a visual and an operational perspective is important. FHWA, in 

collaboration with the International Bridge, Tunnel and Turnpike Association (IBTTA), recently completed a study of traffic control strategies at toll plazas and issued a report entitled, “State of the 

Practice and Recommendations on Traffic Control Strategies at Toll Plazas.” The recommendations 

contained in the report address (1) solutions to improve safety and operations of existing toll plazas; 

(2) contemplating replacement or modification of an existing toll plaza; or (3) planning a new toll 

plaza. While potentially applicable to HOT lanes, the report includes recommendations for Advance 

Signage and the Color of Toll Signs, but does not specifically address HOT operations. Unfortunately, 

The Manual on Uniform Traffic Control Devices (MUTCD) for Streets and Highways 2003 Edition does 

not provide a recommendation or standard for HOT signage. Some current toll agencies and other 

future ORT toll facilities have implemented purple-background signs to differentiate the facility from 

conventional roadways or other toll facilities. The Harris County Toll Road Authority (HCTRA) uses 

purple-background signs on their WestPark Tollway in Houston as part of an Experimentation Project 

(see Section 1A.10 – Interpretations, Experimentations, Changes, and Interim Approvals, pages 1A-4 

through 1A-7 of Chapter 1 from the 2003 MUTCD. The MUTCD 2003 Edition does not prohibit such 

use, but also does not endorse/recommend its use. The two signs14 below where used for conventional toll plazas, but their color distinctions should be considered as an example to provide unique 

and distinct HOT signage.

Figure 4-2: Sample HOT Signage

Since SAFETEA-LU failed to fund the development of the 2008 MUTCD, no new recommendations or 

standards are planned at this time that would include toll roads or HOT lane applications. Until the 

MUTCD provides standards for toll road or HOT signage, it is recommended that agencies or DOT’s 

plan to use purple signs, similar to the HCTRA signs used for the WestPark Tollway, and that that 

application be made to FHWA for an Experimentation Project, similar to the HCTRA project, for use of 

the purple signs. This will permit the use of the signs, while not officially covered by the MUTCD at 

this time.

While the MUTCD currently provides no guidance on signing for HOT lanes it is particularly important 

to have good signage when variable tolls are involved and it is critical in directing motorist to access 

and egress locations. Although MnPass chose not to use purple for their implementation the figure 

here is a good example of a distinctive sign that is in use by MnPass on their HOT implementation 

on I-394. It is clear, easy to understand, and provides the driver with information on the toll and distance to the HOT access. Two additional examples of informative and clear signage are shown in the 

figures below. 

14 Excerpt from FHWA Memorandum, Subject: Traffic Control Signage for Toll Plazas, October 10, 2006,

Sun Pass E Pass
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Figure 4-3: Sample HOT Lane Signage

Signage placement must be located at a sufficient distance to provide the motorist with enough time 

to safely execute the directions provided or to change lane if needed to comply with the signage. The 

chances for operational success of a managed lane facility will be enhanced by good informational 

and directional signs.

It is equally important to ensure that signage displaying enforcement 

provisions for lane violations is displayed consistently and frequently 

along the HOT corridor. It has been found that the lack of consistent 

enforcement signage contributes to unauthorized users accessing the 

facilities. 

Additionally, the inadequacy of enforcement signs also appears to contribute to the practice of lane diving from the general purpose lanes 

into the HOT lanes that are not barrier separated which can create 

safety hazards. 

4.5. Incident Management

The sponsoring agency must develop a comprehensive incident management plan to address a wide range of situations that can impact facility operations. For example, 

if there were a major accident on highway mainlines that resulted in severe backups, should the HOT 

lane eligibility requirements be temporarily waived to maximize corridor-wide throughput until the 

accident is cleared? Conversely, if there were a major incident on the HOT lanes and they were to 

be closed, how should the event be handled? How will necessary information be conveyed and what 

information should appear on VTMS? 

The functional requirements for HOT lanes are best integrated into a region’s traffic operation center. 

The development of a Regional Incident Management Plan that addresses incident types and mitigation options for each type must be developed and updated regularly. For an Incident Plan to be 

effective, the plan must be tested and training on the execution of the plans must be performed on a 

regular basis. If transit operations are integrated in the facility, then transit vehicle incident management must be included in the Incident Management Plan. 

With a regional traffic operations center, on-site personnel may be employed to monitor and address 

traffic incidents and enforce rules and regulations that cannot be addressed remotely. For example, 

although SANDAG’s I-15 Express Lanes is operated by a private company, incident management is 

under the sole control of Caltrans, who make decisions to divert traffic from or onto the Express 

Lanes depending on the nature of the incident. Reversible flow lanes, in particular, must have onsite staffing to ensure safe and efficient opening and closure of lane operation, regardless of the 

Toll Rate Sign

SR 91 MnPass
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level of automation applied to the deployment of traffic control devices. Typically, staffing resources 

varies with the amount of automation, but a minimum of one person per peak period needs to drive 

the lane and make sure all of the traffic control devices are fully deployed in a correct manner.

HOT lanes are increasingly turning to ITS systems to track users, monitor operation performance, 

confirm whether tolls have been paid, and confirm lane status when incidents occur. The implementation of a basic incident detection system must include automated interfaces, typically with video and 

incident detection software application to effectively detect incidents and to deal with regional traffic 

issues in a timely manner.

As soon as the severity of an incident is determined by operations personnel, information on travel 

options should be posted in real time on VTMS and DMS in the area. If Highway Advisory Radio, 

(HAR) is included in the region’s ITS suite of equipment, incident alerts should be announced through 

this medium as well. Along with the message sign and HAR notifications, website posting of separate 

real-time travel speeds, travel options, and service reliability for the HOV lanes should also be used. 

In some cities such as Atlanta, Seattle, Houston and Orange County, California, website postings are 

already occurring, enabling users to quickly assess incident travel options, and available travel benefits between the parallel roadways. 

Functional requirements for the HOV/managed lane system should be reviewed periodically as design 

upgrades in technology and traffic operations management allow.
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Considerations for High Occupancy Vehicle (HOV) to 

High Occupancy Toll (HOT) Lane Conversions Guidebook

Chapter 5. Case Studies of HOT Lane 

Conversion Projects

Chapter 5. Case Studies of HOT Lane Conversion 

Projects

The purpose of this chapter is to identify lessons learned from three case studies of HOV to HOT conversion projects:

- I-15 Express Lanes (San Diego, CA)

- MnPass (Minneapolis, MN)

- I-25 Express Lanes (Denver, CO)

Figure 5-1: Location of Hot Lane Case Studies

These three case studies were chosen to supplement the growing body of research exploring the 

relationship between program objectives, system design, concept of operations, toll collection strategies and operational requirements. Each case studies attempts to identify outcomes (intended and 

unintended) based on specific operational choices and address key lessons learned, or best practices in the planning, design and implementation. 

5.1. Data Collection Approach

Information available form published data for each of the operational case study sites was integrated 

with focused interviews conducted at the project site, when possible. To provide a common baseline, 

or starting point for the interviews, a focused interview guide was developed to facilitate in-depth 

probing of key project development issues and challenges in four main areas, including:

- Public Outreach and Communications 

- Planning and Policy 

- System Design Procurement 

- Management and Operations

San Diego, CA

I-15 Express Lanes

Denver, CO

I-25 Express Lanes

MnPass

Minneapolis, MN
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Chapter 5. Case Studies of HOT Lane 

Conversion Projects

5.2. Focused Interviews

The three systems were specifically chosen for the case studies because they were converted from 

HOV lanes to HOT lanes or were in the planning process for expanding existing facilities to HOT lanes 

and had been operational for at least one year.

On-site interviews with the management and operations staff were conducted at the I-15 Express 

Lanes in San Diego, California and MnPass in Minneapolis, Minnesota. For I-25 Express Lanes in 

Denver, Colorado, remote discussions were conducted with key management staff. As mentioned 

previously, the interviews were designed to address specific issues and challenges faced at each 

stage of project development to include public outreach, planning, design, implementation and operations. Tables 5.1 and 5.2 provide a comparative summary comparison of the three operational case 

sites key site properties and operational characteristics.

Table 5-1: Facility Characteristics

Site Length Type Lane # Access Points

Toll

Points GP – ML Separation

I-394 11 mi 8 mi – SLn

3 mi – 2Ln Rev.

Multiple – SL

Rev. Entry / Exit

7 WB

6 EB

Double White, Rev. with 

Barrier

I-15 8 mi 2 Ln Rev. Entry / Exit 1 Rev. with Barrier

I-15 

Exp

12 mi 2 Ln HOT Multiple Multiple Dbl Yellow, Movable Barrier

I-25 10 mi 3 mi SLn

7 mi 2Ln Rev.

Entry / Exit 1 Dbl White, Rev. with Barrier

Note: I-15 HOT expansion includes four lanes (two in each direction), with movable barrier separation 

in southern section and double yellow strip separation in northern section between HOT and general 

use lanes. 

Table 5-2: Operational Characteristics

Site Open Type Hours of Ops Authorized Users Tag 

Requirement

I-394 2005 SL HOT

R2L HOT

AM Peak

PM Peak

Non-Peak Closed

2 axle, HOV+2 

Buses

Only SOV 

I-15

Rev

1996 R2L HOT AM Peak

PM Peak

Non-Peak Closed

2 axle, HOV+2 

Buses

Only SOV

I-25 2006 SL HOT

R2L HOT

AM Peak

PM Peak

Non-Peak Closed

Trucks, HOV+2 

Buses

SOV, Bus, 

Truck

The following sections briefly summarize the key findings from the focused interviews for each of the 

operational sites, SANDAG’s I-15 Express Lanes, MnDOT’s MnPass, and CDOT’s I-25 Express Lanes. 
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High Occupancy Toll (HOT) Lane Conversions Guidebook

Chapter 5. Case Studies of HOT Lane 

Conversion Projects

5.3. San Diego, CA I-15 Express Lanes

The I-15 Express Lanes (FasTrak) opened in January 1997 as a three year value pricing demonstration that has been operational since transitioning from HOV only to HOT Express Lanes in January 

2000. The original facility was an 8-mile, two lane, reversible HOV facility. With over 10 years of 

operational experience, SANDAG will expand the existing reversible facility to four bi-directional HOT 

lanes with multiple intermediate access locations of over 20 miles in length. 

5.3.1. Project Objectives

- Provide additional highway capacity on what had been a largely underutilized HOV facility.

- Provide better management and utilization of the HOV lanes.

- Achieve and maintain LOS C or better.

- Generate enough revenues to support ongoing operations and maintenance.

- Support new express transit service through toll revenues.

- Improve highway and transit in the corridor. 

- Extend the original reversible lane segment to include and additional 12 miles of converted HOV 

lanes into an HOT corridor.

5.3.2. Concept of Operations

- The reversible section was operational only during the AM and PM peak periods and closed during 

the non-peak period.

- As the facility expands operations for both HOV and HOT will be 24/7. System will use movable 

barriers on the new extension. 

- As with the existing reversible sections, HOV 2+ and transit will travel at not cost (free) while 

SOVs will be tolled for use of the facility. Trucks will not be permitted to use the facility.

- Current policy only requires SOV users to have a transponder. However, transponder use for HOV 

users is under consideration.

- While under consideration, there is currently no electronic enforcement, only manual enforcement 

provided by enforcement officers.

- Dynamic Pricing has been employed from the initial pilot system. Toll rates vary, on average from 

$.50 to $4.00 with a maximum of $8.00.

5.3.3. Innovative Project Features

- Having local and state leadership engaged in discussions early and often throughout the planning 

and design phases.

- Using dynamic pricing with adjustments based on time of day, congestion levels, and travel time 

differential with the general purpose lanes. Rates may be adjusted every 6 minutes.

- Sharing revenues with BRT in corridor widely accepted by transit agencies and the public.

5.3.4. Major Project Challenges/Mitigation Actions

- Higher risk of SOV use violations with continued manual enforcement by CHP – Prior to the expansion of the I-15 Express Lanes, enforcement was easier because it was a reversible lane facility 

that allowed access at a single toll point, with wide shoulders and one enforcement area. With 

multiple access points and limited shoulder widths, mobile enforcement will be needed to effectively target toll violations.

- The implementation of dynamic pricing required both local public and political support. Early and 

frequent (on-going) public awareness initiatives that included public outreach, active marketing 

and surveys contributed to the ready acceptance of dynamic pricing.
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Chapter 5. Case Studies of HOT Lane 

Conversion Projects

5.3.5. Major Lesson Learned

- Enlist the support of a strong political champion at both state and local levels to provide advocacy 

for HOT lane conversion.

- Roll out an extensive public outreach program involving stakeholder interviews, focus groups, and 

taskforces in parallel with early project planning efforts.

- Conduct corridor level market research early in the project and update frequently. 

- Share information and research among other agencies, especially those involved along the 

corridor.

- Recognize the need for employing ITS technology to enhance the program and for adding to 

regional ITS capabilities.

5.3.6. Keys to Project Success

- The HOT program must provide viable and recognized travel options for the public.

- For project acceptance strong stakeholder and public outreach programs are a necessity.

- When possible it is important to develop a revenue plan that includes a transit component. 

5.4. Minneapolis, MN I-394 Express Lanes

The I-394 Express Lanes, better known as MnPass, became operational in May 2005 and has nearly 

two years of operational lessons learned since it opened.

5.4.1. Project Objectives

- To improve efficiency of I-394 and to increase person and vehicle carrying capabilities of the HOV 

lanes.

- To maintain free flow speeds for transit and carpools.

- To improve highway and transit operations in the corridor with the revenues generated.

- To use electronic toll collection without toll booths.

- To employ dynamic pricing and in-vehicle electronic enforcement.

5.4.2. Concept of Operations

- Conversion of the existing HOV lanes to HOT lanes with concurrent travel to be operated 24/7 

while operating the two-lane reversible section for HOT operations EB during the AM Peak and WB 

for the PM Peak. 

- Only SOVs are tolled while HOV 2+ and Transit are not tolled (free). Trucks are not permitted to 

use the facility.

- For the non-reversible section there is no barrier between the HOT lanes and adjacent GP lanes. 

Only double white stripe is used to delineate HOT-GP separation.

- For the HOV converted segment there are multiple mid-point access locations to the HOT facility. 

Access to and from the reversible lane segment is controlled by three gates that are closed manually prior to beginning reverse operations.

- Variable dynamic tolling is used during peak travel times with an average toll rate between $1 and 

$4, with a maximum of $8.

5.4.3. Innovative Project Features

- The engagement of state leadership early and often throughout the planning and design phases 

was instrumental in passing key legislation and project acceptance.

- A local taskforce, the I-394 Express Lane Community Taskforce, was created to address issues, 

desires and design options.
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Chapter 5. Case Studies of HOT Lane 

Conversion Projects

- The program received local and state support by ensuring that 50% of revenues generated were 

shared with transit for improvements.

- To maintain support and to encourage continued growth, it is important to conduct continuing 

and comprehensive evaluations of the facility to provide to the public and for use in marketing 

campaigns. 

5.4.4. Major Project Challenges/Mitigation Actions

- Prior to the conversion to HOT lanes there was a high rate of HOV lane violations, over 20%. To 

maintain the integrity of the HOT facility a more effective enforcement presence was needed to 

detect and to deter violators. Mobile violation detection equipment was employed along with 

contracts with three law enforcements agencies along the corridor to beef up law enforcement 

presence. Contracts are with Minnesota Highway Patrol, Minneapolis Police Department and the 

Golden Valley Police Department. 

- Opposition from pro-transit constituent groups had to be convinced that HOT lanes would provide 

a strong benefit to transit. With the strong projections provided from the Toll and revenue studies, 

and the proposed sharing of the revenue generated, the pro-transit constituent groups became 

strong supporters.

- The added SOV traffic on the HOT lanes created unexpected traffic backups in the downtown area 

that increase congestion. After opening of the HOT facility MnDOT constructed an auxiliary lane to 

provide additional vehicle storage capacity to mitigate the congestion created by the added SOV 

traffic.

5.4.5. Major Lesson Learned

- Have a fiber backbone and communications infrastructure in place to implement an effective traffic management system. 

- The establishment of the I-394 Express Lane Community Task Force was critical to getting buy-in 

from the Governor, state legislators, and community groups. It provided an opportunity for the 

community to engage the decision makers early and often through a participatory process.

- Don’t create new traffic problems and be prepared to add capacity to address unexpected congestion hot spots.

5.4.6. Keys to Project Success

- Implement an effective enforcement strategy to regulate demand and to maintain the integrity and 

effectiveness of the facility.

- Establish a robust public outreach and coordination framework through which to build political and 

public support.

- Develop a revenue plan that featured a transit component was critical in earning the trust and support of the transit community.

5.5. Denver, CO I-25 Express Lanes

The I-25 Express Lane opened in June 2006. Like SANDAG’s I-15 Express Lanes, I-25 Express Lanes 

consists of two segments: a 2-mile reversible segment and a 7-mile barrier-separated HOT lane 

segment.

5.5.1. Project Objectives

- Improve the efficiency and capacity of I-25 HOV/HOT lanes.

- Expand menu of travel options to the motoring public.
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Chapter 5. Case Studies of HOT Lane 

Conversion Projects

- Use the facility as a showcase congestion management tool.

- Generate sufficient revenue to cover operating expenses.

5.5.2. Concept of Operations

- The reversible section is operational during AM and PM peak periods. During non-peak periods 

the section is open outbound only.

- The HOT section (converted HOV) is only operational during the AM and PM peak periods.

- The entire facility is barrier separated with single entry and exit points. 

- SOV’s are tolled for use, while HOV2+ and transit travel without being tolled (free). Trucks over 

3-axles using the facility are charged a premium rate of $18.00 plus the base toll rate which is per 

axle based.

- All HOT users, SOV, bus and trucks are required to have transponder.

- A fixed variable toll rate based on time of day dynamic tolling is used. Toll rates average between 

$.50 to a maximum of $3.25).

- VES enforcement is automatic using license plate photo and optical character recognition 

technology.

5.5.3. Innovative Project Features

- Instead of using LOS, bus travel speed is used as a performance measure on travel time. If bus 

speeds or time degrades by 8 min, 45 seconds then the toll rate is raised to push SOVs off of the 

facility. The tolls are increased on a pre-determined fixed amount based on time of day.

- The facility has single ingress and egress points with the northern section interfacing to two distributor connections and the southern end feeding directly into downtown.

- The facility has a single tolling point that requires traffic to divide into lanes for HOVs (free) and 

non-HOV (tolled) vehicles.

- During off peak hours the reversible lanes are switched using multiple gates along the facility to 

restrict access from direct access ramps. All gate closing is completely automated.

- Customer Service Center is outsourced to existing E-470 Service Center

5.5.4. Major Project Challenges/Mitigation Actions

- HOV/HOT violations are captured automatically for undetected transponder reads using V-tolls, or 

video tolls.

- Vehicle occupancy violations done by visual on-site inspection by Highway Patrol.

- Automatic vehicle classification system is required for axle classification needed to capture trucks 

with more than three axles. 

- The reversible lane section in downtown required that travel through the section be safely and efficiently revered. Gates are used at the entrance and exit points as well as the direct access ramps 

to restrict access. Gate closing is completely automated, is done during off-peak hours is connected with traffic operations via a verifiable communication link to verify gate status.

5.5.5. Major Lesson Learned

- Have a political champion to ensure successful project implementation.

- Avoid justifying HOT lanes implementation as a revenue generation strategy for added capacity. 

Establish the primary program objective of HOT lane implementation as a congestion management 

tool.

- Ensure that managed lane projects are included in MPO plans early.
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Chapter 5. Case Studies of HOT Lane 

Conversion Projects

5.5.6. Keys to Project Success

- Promote future projects as “congestion relief” and promote early to the public. Don’t promote revenue enhancement; advocate use as a congestion tool.

- An effective enforcement strategy is a must for a success.

- A strong political champion at both state and local levels is key to successful project development 

and implementation.
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Chapter 6. Direction for 

Future Practice

Chapter 6. Direction for Future Practice

The success of HOT lanes in a growing number of states suggests that there is a strong market 

demand for high quality, dependable Express Lanes that function as a safety valve from highway 

congestion. However, the case studies, in addition to the experience of new HOT lane projects elsewhere, indicate that HOT lanes – while they demonstrate the feasibility of several important operational concepts – are assets that have diminished valuation compared to other toll alternatives. 

While there may be a compelling financial case for requiring all vehicles to pay a toll regardless of 

occupancy, the opportunity to leverage private financing and PPP mechanisms must be weighed 

against program objectives developed specifically to mitigate public concerns such as equity, fairness and privacy. In many cases, there is a strong consensus to accept suboptimal rates of return in 

exchange for mitigations that demonstrate the state’s commitment to meeting public concerns. 

As more agencies assess the feasibility of converting existing HOV to HOT lanes, it is important that 

planners, designers and other practitioners avoid ‘relearning’ lessons others have struggled with 

in converting HOV lanes to HOT lanes. One of the biggest challenges facing HOT lane planning and 

operations is and will continue to be enforcement. Perhaps the major lesson learned from the case 

studies is that while manual enforcement is imperfect, it can be an effective method of deterring violations in HOT lanes with limited access. Even with multiple enforcement zones, it is virtually impossible for law enforcement to perform 100% occupancy checks of vehicles that self-identify as HOVs.

This is especially true of HOT lane that are non- barrier separated and have multiple access points. 

As HOT lane facilities expand in length and grow from a facility-based to network-based system, 

manual enforcement will at some point experience diminishing effectiveness as a violation deterrent 

strategy. The following section briefly identifies the Best Practices Top 20 highlighting those areas 

HOT lane practitioners should be cognizant of to avoid problems and challenges that may arise during each phase of project development and implementation. 

6.1. Best Practices

The purpose of this section is to identify best practices in each of the major stages of project development, per the discussion in Chapter 2. The best practices identified here are informed by information gathered as part of the focused interviews and research conducted on HOT implementation 

projects completed over the past 15 years. 

6.1.1. Project Pre-Planning and System Planning

- Engage local and state leadership early and often during planning and design phases.

- Develop an extensive and effective Public Outreach Program that begins at the earliest stages and 

continues through operations.

- Ensure that the HOT project is included in the MPO planning requirements as soon as possible.

- Identify a strong Political Champions at the State and Local levels willing to advocate the HOT conversion project and participate in efforts to build support for the HOT conversion program. 

- Foster a revenue and sharing plan that includes transit when possible to do so.

6.1.2. System Design

- Design for efficiency, safety and ease of participation by the public. 

- Provide the public with a viable travel option. 

- Utilize electronic and video tolling concepts; no toll booths.

- Consider using dynamic tolling strategies to control traffic volumes.
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6.1.3. Project Financing

- Federal funds and grants are essential to implementing a project. 

- Investigate PPP options either as stand alone or as supplemental to Federal funding. 

- Use local Special Purpose Local Option Sales Tax (SPLOST) options as appropriate to address 

short falls. 

6.1.4. Implementation

- Utilize electronic and video tolling concepts. 

- Consider outsourcing back office and/or Customer Services with an established Customer Service 

Center. 

- Ensure the establishment of maintenance services to provide 24/7 operations to include an OnLine Maintenance System (MOMs). 

6.1.5. Operations and Management

- Determine if 24/7 toll operations meets objectives and is generally supported by resources and 

the public. 

- Use dynamic pricing strategies to maintain free flow speeds. 

- Implement an enforcement system that is visible, effective and fair (from the public’s perspective) 

to ensure the integrity of the facility.

- Share information and research with agencies along the corridor to obtain their support and 

ensure the success of the facility.

- Implement a continuing and comprehensive evaluation of the facility to maintain support, to 

encourage continued growth, to use in marketing campaigns and to inform the public.

6.2. Lessons Learned

Although each of the case studies differed from one another and from a number of the implementations reviewed in the literature, there were several project development issues and challenges around 

which key lessons learned with similar themes were articulated. The lesson learned that resonated 

across several projects are presented here to alert and to assist practitioners to challenges likely to 

be encountered throughout the project development process.

1. Every HOV to HOT conversion project needs a political champion with strong credibility among 

state, regional and locally elected officials. Based on the case studies, the presence of a political champion at both the State and local levels was critical in building support within the State 

Legislature and developing mitigation strategies for potential deal-breakers.

2. An extensive public outreach program with stakeholder outreach, a multi-agency taskforce, public meetings are absolutely necessary for success and acceptance. A successful program built 

around three or four program objectives is critical for obtaining buy-in with the public and with 

elected officials.

3. HOT lanes should not be implemented as a revenue generator for added capacity. They should 

be ‘sold’ to the public and implemented as a congestion management tool first and a possible 

source of revenue second.

4. It is critical to fully understand the impact of creating added capacity to HOV lanes and potentially creating unexpected, new congestion hot spots.
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5. Enforcement of occupancy requirements is the most difficult operational challenge facing toll 

agencies and enforcement officers because automatic technologies have not yet met reliability 

and field accuracy requirements required for operational deployment. 

6. Signage among the various tolled facilities was not consistent especially when announcing 

enforcement provisions for lane violations. This lack of consistent enforcement signage was 

found to contribute to unauthorized users accessing the facilities and appeared to contribute to 

the practice of lane diving from the general purpose lanes into the managed lanes that were not 

barrier separated.

6.3. Direction for Future Practice

Tolling and dynamic pricing are gaining greater recognition among the State DOT’s as a means of 

generating revenues for system improvements and for managing increasing traffic levels. Each HOV 

transition to HOT operations will, by necessity, be evaluated on the unique circumstances for each 

area. While each implementation will be a unique application dependent on road geometry, right of 

way availability, density and alternative corridors, it is important that consideration be given to the 

utilization of common, and to some degree, interoperable technologies for a HOT facility. 

Some trends and practices that are emerging throughout the nation as HOT lane implementations 

grow include 

6.3.1. Legislative

Legislatures are becoming more proactive in providing enabling legislation that will provide the 

states with the authority to collect tolls, to toll HOV facilities, to implement an effective violation 

enforcement policy, to provide authorization to collect administration and processing fees, and to provide for a PPP policy.

6.3.2. Electronic and Video Toll Payment

To minimize the impact to the traveling public, toll booths will not be used for HOT lane operations. 

As congestion increases and the average number of HOT lane facilities increases to beyond 2 lanes 

in each direction, the HOT implementations will begin to resemble ORT) implementations using a 

combination of electronic and video tolling.

6.3.3. Enforcement

As was mentioned numerous times, enforcement is critical to the successful operation of any HOV/

managed lane facility. Visible and effective enforcement promotes fairness and maintains the 

integrity of the facility to help gain and maintain public acceptance of the project. Continued technology improvements will provide effective video capture and optical character recognition systems 

for license plate capture. However, these improvements alone will not be sufficient for an effective 

enforcement system. It will be necessary to implement a reliable and accurate mobile enforcement 

system that complements the improved video systems. Visible and effective enforcement promotes 

fairness and maintains the integrity of the facility to help gain and maintain public acceptance of the 

project.

6.3.4. Occupancy Enforcement

Probably the most frequent type of violation infraction that enforcement officers encounter is occupancy violations, which requires them to see inside a vehicle and to be able to count the number of 

occupants. Current technology does not exist to determine accurately the number of occupants in 
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Chapter 6. Direction for 

Future Practice

a vehicle. However, perhaps within the next ten to fifteen years an on board unit capable of determining vehicle occupancy will be fully integrated in a vehicle and capable of communicating this 

information to the enforcement officer at the roadside using DSRC technology. Until this technology 

is available it is likely that DOT’s and toll agencies will require all HOT users to establish either a transponder or a video toll account to assist in separating HOV authorized users from SOV users.
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Chapter 7. List of Acronyms

Chapter 7. List of Acronyms

Acronym Description

AASHTO American Associate of State Highway and Transportation Officials

AVC Automatic Vehicle Classification

AVI Automatic Vehicle Identification

BRT Bus Rapid Transit

CCTV Closed Circuit Television

CDOT Colorado Department of Transportation

CHP California Highway Patrol

CSC Customer Service Center

CTOC California Toll Operators Committee

DOT Department of Transportation

DSRC Digital Short Range Communication

DVAs Digital Video Audit Systems

EB Eastbound

ETC Electronic Toll Collection

FHWA Federal Highway Administration

HCTRA Harris County Toll Road Authority

HOT High Occupancy Toll

HOV High Occupancy Vehicle

IBTTA International Bridge, Tunnel and Toll Authority

ITS Intelligent Transportation Systems

LOS Level of Service

LOV Low Occupancy Vehicle

MnDOT Minnesota Department of Transportation

MOM Maintenance Online Monitoring

MPO Metropolitan Planning Organization

MUTCD Manual on Uniform Traffic Control Devices

NTDEV Notic of Delinquent Toll Evasion

NTEV Notice of Toll Evasion

NTP Notice to Proceed

OCR Optical Character Recognition

OCTA Orange County Transportation Authority

ORT Open Road Tolling

PPPs Public Private Partnerships

RFID Radio Frequency Identification

RFP Request For Proposal

RPOs Regional Planning Organizations

RTMS Remote Traffic Microwave Sensor
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Chapter 7. List of Acronyms

Acronym Description

SAFETEA-LU Safe, Accountable, Flexible and Efficient Transportation Equity Act: A Legacy for Users

SANDAG San Diego Association of Governments

SOV Single Occupant Vehicle

SPLOST Special Purpose Local Option Sales Tax

TDM Transportation Demand Management

TSM Transportation System Management

TxDOT Texas Department of Transportation

VES Violation Enforcement System

VMS Variable Message Sign

VPC Video Processing Center

VTMS Variable Toll Message Sign

WB Westbound
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Chapter 8. References

Chapter 8. References

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Obenberger, J. Managed Lanes. Public Roads. Federal Highway Administration, U.S. Department of 

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Parsons, Brinckerhoff, Quade and Douglas. HOT and TOT Feasibility Studies for the Atlanta Region. 

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Poole, R. and C.K. Orski. HOT Lanes: A Better Way to Attack Urban Highway Congestion, Regulations 

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Supernak, J., D. Steffey, and C. Kaschade. Dynamic Value Pricing on I-15 in San Diego: Impact on 

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Contact Information

For additional information on this report, contact 

Jessie Yung, P.E., via e-mail at Jessie.Yung@dot.gov.

Federal Highway Administration

1200 New Jersey Avenue SE

Washington, DC 20590

June 2007

Publication #FHWA-HOP-08-034 07.156.08