Technologies That Enable 

Congestion Pricing

A Primer
Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high quality 

information to serve Government, industry, and the public in a manner 

that promotes public understanding. Standards and policies are used to 

ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its 

programs and processes to ensure continuous quality improvement.
Contents

The Primer Series and the Purpose of This Volume 2

Congestion-Pricing Options 4

Functional Processes for Tolling and Congestion Charging 6

Primary Tolling and Pricing-System Components 7

Paper-Based Systems 7

Manual-Toll Facilities 8

Image-Based Tolling/Automatic License Plate Recognition (ALPR) Technology 9

DSRC Free-Flow Toll Using Transponders and Gantries 9

VPS Technologies 11

Cellular Telephone and Pico-Cell Systems 12

Combination Systems 13

Sub-System Technologies 14

Informing and Providing Standardized Signs and Lane Markings 14

Vehicle-Occupancy Detection Technologies 15

Vehicle-Identification and Classification Systems 15

Telecommunications: Roadside and Centralized Control Equipment 16

Automation of Operations 17

Payment Systems for Pre- and Post-Payment of Tolls and Charges 17

Secondary Enforcement 18

System Reliability and Accuracy of DSRC Systems 18

OBU Distribution Facilities 19

ITS Integration 19

Acronym List/Glossary 20

References 23
2 | C o n g e s t i o n P r i c i n g

The Primer Series and the Purpose of This Volume

States and local jurisdictions are increasingly discussing congestion pricing as a strategy for improving transportation system performance. In fact, 

many transportation experts believe that congestion pricing offers promising opportunities to costeffectively reduce traffic congestion, improve the 

reliability of highway system performance, and improve the quality of life for residents, many of whom 

are experiencing intolerable traffic congestion in regions across the country. 

Because congestion pricing is still a relatively new 

concept in the United States, the Federal Highway 

Administration (FHWA) is embarking on an outreach effort to introduce the various aspects of 

congestion pricing to decision-makers and transportation professionals. One element of FHWA’s congestion-pricing outreach program is this CongestionPricing Primer Series. The aim of the primer series is 

not to promote congestion pricing or to provide an 

exhaustive discussion of the various technical and 

institutional issues one might encounter when implementing a particular project; rather, the intent is 

to provide an overview of the key elements of congestion pricing, to illustrate the multidisciplinary 

aspects and skill sets required to analyze and implement congestion pricing, and to provide an entry 

point for practitioners and others interested in engaging in the congestion-pricing dialogue. 

The concept of tolling and congestion pricing is 

based on charging for access and use of our roadway 

network. It places responsibility for travel choices 

squarely in the hands of the individual traveler, 

where it can best be decided and managed. The car 

Technologies That Enable 

Congestion Pricing

This volume explores transportation 

technologies that enable congestion 

pricing. This document considers 

the following:

•	 The functional processes for

tolling and congestion pricing.

•	 What technologies there are to

consider.

•	 How the technologies are applied.

•	 Examples of how technologies

have been applied.

•	 What technologies may make it

work better in the future.

About This Primer Series

The Congestion Pricing Primer Series is part of FHWA’s outreach efforts

to introduce the various aspects of congestion pricing to decision-makers 

and transportation professionals in the United States. The primers are 

intended to lay out the underlying rationale for congestion pricing and 

some of the technical issues associated with its implementation in a 

manner that is accessible to non-specialists in the field. Titles in this 

series include:

•	 Congestion Pricing Overview.

•	 Economics: Pricing, Demand, and Economic Efficiency.

•	 Non-Toll Pricing.

•	 Technologies That Enable Congestion Pricing.

•	 Technologies That Complement Congestion Pricing.

•	 Transit and Congestion Pricing.

•	 Income-Based Equity Impacts of Congestion Pricing.
T e ch nologies Tha t E n a ble Congestion Pri c ing | 3

is often the most convenient means of transportation; however, with a little encouragement, people 

may find it attractive to change their travel habits, 

whether through consolidation of trips, car-sharing, 

by using public transportation, or by simply traveling 

at less-congested times. The use of proven and practical demand-management pricing, which we freely 

use and apply to every other utility, is needed for 

transportation. 

The application of tolling and road pricing to solve 

local transportation and sustainability problems provides the opportunity to solve transportation problems without federal or state funding. It could mean 

that further gas tax, sales tax, or motor-vehicle registration fee increases are not necessary now or in the 

future. The idea of congestion pricing is a conceptual 

first step, not a complete plan of action. It has to be 

coordinated with other policy measures and environmental measures for sustainability. 

This toll-technology primer was produced to examine the use of technology, both primary and advanced, to support tolling and congestion pricing. It 

explains how current tolling and congestion-pricing 

technology works and what technologies may make 

it work better in the future. 
4 | C o n g e s t i o n P r i c i n g

Congestion-Pricing Options

In the United States and around the world, several 

strategies exist on how to implement congestion 

pricing. These strategies consider how best to influence traffic patterns, match the local geography, fit 

political boundaries, and match the policy framework of the implementing jurisdiction. 

The four major types of pricing include:

•	 Priced Lanes: Fees for low-occupancy vehicles to 

utilize excess capacity on new or existing highoccupancy vehicle (HOV) lanes (e.g., I-15 FasTrak® between Kearny Mesa and Rancho Penasquitos, California1

, or the SR-91 Express Lanes in 

Orange County). Pricing can be fixed per road 

segment, vary by occupancy (e.g., HOV2, HOV3, 

or HOV4+), vary by occupancy and time of day, 

or vary dynamically based on the degree of congestion in the adjacent “free” lanes. 

•	 Variable Tolls on Entire Roadways: Fees placed 

on existing and new roads, bridges, and tunnels 

to pay for access onto the road or facility and to 

pay for the cost of maintenance and construction 

of the road, whether the government or the private sector builds the toll facility. The toll is variable, that is, prices rise and fall depending on the 

measured traffic level or estimated traffic level 

based on time of day.

•	 Zone-Based Charges: Fees levied to charge for 

access or use of a designated road network in 

and around heavily congested areas or urban 

centers. There are several forms of congestion 

pricing, including cordon charges, area charges, 

and zonal charges. These variations are explained 

as follows: 

– Cordon charge—A flat or variable fee levied for 

crossing the designated boundary around an 

urban center. Cordons can be used for entrance 

or exit of any road designated by the cordon(s). 

Manchester, England, has proposed a cordon 

charge to enter the regional center only during 

the morning peak period inbound and the evening peak period outbound. It uses the natural 

boundary of the M-60 motorway, which circles the regional center and city of Manchester, 

and includes a proposed second cordon boundary closer to the city center. Stockholm is an 

example of a single cordon charge. 

– Area charge—Charge for all trips whether 

they originate outside the boundary and cross 

the designated boundary or originate inside 

the boundary and never cross the boundary 

during the charging period. The London Congestion Charging System levies a flat fee on 

any vehicle on public roads inside the designated charging zone or crossing into or out of 

the boundary. It also charges the same daily 

fee for all vehicles regardless of size or time 

spent in the charging zone. 

– Zonal charge—Mini-cordons within or around 

an urban center where fees are charged for 

entering each mini-cordon that can be contiguous or spatially separated with free roads 

in between them. Charging for each minicordon can be the same across all cordons or 

vary between them and can also vary by direction or time of day for peak-period charging 

or variable charging based on the degree of 

congestion. Mini-zones are typically drawn 
T e ch nologies Tha t E n a ble Congestion Pri c ing | 5

around known geographical or political boundaries that are easily and clearly understood by 

the local residents. Florence, Italy, has several 

mini-cordons based on centuries-old political 

boundaries. Residents of any specific mini-cordon are not charged for travel within their 

“home cordon” but are charged for entry into a 

neighboring mini-zone or cordon. 

•	 Area-Wide or System-Wide Charges: Fees levied 

on a vehicle based on factors such as vehicle 

type, distance traveled, time of day, type of road, 

vehicle emissions, or type of power train (e.g., 

diesel engine, gasoline engine, bio-fuel engine, 

hybrid, electric, or hydrogen). This type of charging includes:

– Truck or heavy commercial vehicle pricing—

Fees levied only on trucks or heavy commercial vehicles that typically reflect charges for 

the weight carried (load) and distance carried 

on the road network. Current truck pricing 

examples include New Zealand’s Road User 

Charging, Switzerland’s truck tolling, and 

Austria’s and Germany’s MAUT systems. 

– Strategic-road-network charge—Levies imposed 

as spot charges on major roads or congested 

network links in or into city centers. Strategicroad-network charges can be a continuous series of charging points along a major access 

road into the urban center. These charges can 

vary by location and time of day, in addition to 

type or classification of vehicle. Strategic-roadnetwork charges were considered in the Auckland, New Zealand, Road Pricing Evaluation 

Study(2) and are part of the Singapore Electronic Road Pricing (ERP) system.(3) In Singapore, these charges apply not only on the strategic road network approaching the central 

business district (CBD), but also to specific 

congested areas or streets inside the boundary 

of the cordon charge.(3)

These options define the major types of pricing that 

exist today, but the list is not all inclusive, and new 

concepts or combinations of the above may develop 

in the future. For example, Milan, Italy, has introduced an environmental charging system, and Hong 

Kong has explored a concept of eco-point charging 

or personal carbon-based trading in which users 

gain or lose “eco-points” based on their travel choices, time, and distance traveled.(4)

 
6 | C o n g e s t i o n P r i c i n g

Functional Processes for Tolling and 

Congestion Charging

The basic function of any tolling or congestion-pricing system and supporting technologies is to collect 

payment from users. This can vary significantly depending on particular local conditions; policy framework; strategic, legal, and policy requirements; and 

the nature of the outcomes that the charging system 

seeks to achieve. The capabilities and/or limitations 

of the technologies available have often played a major role in shaping functional design: As the capabilities of technology have increased, the flexibility of 

tolling and road-user charging can more directly address and improve the key objectives. In the same 

way that some technology limitations have restricted 

(and still restrict) some desirable options and functions, the rapidly developing capabilities of new 

technologies can also offer options that may previously have not been considered. 

Whatever system or technology solutions are adopted, the collection of payment from users within 

the framework of any tolling or road-user pricing 

scheme must include consideration of the following 

nine functional requirements:

1. Informing: Providing adequate information to 

users and potential users (often defined by legislation).

2. Detection: Detecting, and in some cases measuring, each individual instance of use (e.g., vehicle 

entering a zone).

3. Identification: Identifying the user, vehicle, or in 

some cases numbered account.

4. Classification: Measuring the vehicle to confirm 

its class, aligned with the classification framework for the scheme.

5. Verification: Cross-checking processes and secondary means of detection to assist in confirming 

transactions, reducing processing costs, and providing a backup for potential enforcement.

6. Payment: Pre- and post-use collecting of payment from users based on verified use.

7. Enforcement: Providing the means to identify 

and prosecute violators and/or pursue violators 

for payment of charges and/or fines.

8. Exemptions: Providing the facility with the means 

to manage a range of exemptions and discounts 

within the context of the scheme.

9. System Reliability and Accuracy: Providing all of 

the above through cost-effective systems and 

technologies that can meet the required levels of 

reliability and accuracy and minimize revenue 

leakage and fraud. 

This base functional framework has been used 

through several of the following sections of this 

primer to consider and compare the functional capabilities and operation of candidate technologies and 

example systems.
T e ch nologies Tha t E n a ble Congestion Pri c ing | 7

The following sections describe the primary system 

technologies and provide examples of locations 

where they are being used. Along with the more 

advanced technologies, this list also includes basic 

systems such as paper-based and manual facilities. 

This is partly for completeness, but it is also to assist 

in better illustrating and describing the basic functions for a simple system that will improve understanding through the later more complex options. 

Paper-Based Systems

Paper-based systems require road users, who wish 

to use (or keep) their vehicles within a defined area 

during a defined time period, to purchase and display a supplementary license or permit. This usually 

takes the form of a paper license displayed on the 

vehicle’s windshield or dashboard as shown by the 

examples provided on this page. 

There are two main options for implementing 

paper-based schemes:

•	 Entry Permit Schemes: Vehicles display a valid 

license sticker to enter (or leave) a defined area 

(the restricted zone). 

•	 True Area Licensing Schemes: Vehicles display a 

valid license to travel or park within a defined 

area.

The distribution of permits or licenses is usually 

managed through a combination of existing retail 

outlets and other system operator channels, such as 

vending machines, the Internet, and phone-based 

mail order. For tolling, coupon books have been 

used in a number of facilities. In the Baltimore Harbor Tunnels, a user can purchase a book of 10 coupons for paying the toll at a discounted price.

 Singapore’s Area Licensing Scheme, which operated from 1975 until 1998, required car drivers 

entering the CBD during the morning peak period 

to pay three Singapore dollars per day (with exemptions for vehicles that carried four or more 

people). This was managed by using a paper-based 

Example of paper license used in the United Kingdom.

Example of a paper license used in Singapore.

Primary Tolling and Pricing-System Components
8 | C o n g e s t i o n P r i c i n g

(sticker) system with stickers purchased for each 

day and placed on the inside of the windshield. 

Drivers were able to travel into and around the 

priced area several times a day without paying multiple charges. Enforcement was addressed at checkpoints where officials inspected each vehicle to ensure a valid license was displayed.

Street-based equipment is generally provided for 

the distribution of permits or licenses. The need for 

and location of permit or ticket vending machines 

vary by system but in most cases can be installed to 

suit the local environment. More advanced units 

can be installed with built-in mobile communications and solar power units, which require no direct 

connections to street services.

Manual-Toll Facilities

Manual-toll facilities, toll booths, or plazas have 

been used around the United States and the world 

for many years and comprise payment points at 

which drivers pay a charge by using cash, vouchers, 

charge cards, credit cards, or smart cards. Some of 

these manual-tolling systems are still in use today. 

Replacement modern versions have changed little 

in that a manual-toll terminal or cash register is 

used to collect and record the toll or charge while a 

traffic light and automatic boom gate hold the car 

present in the toll lane until payment is made. At 

one time, on facilities such as the Pennsylvania 

Turnpike, New York State Thruway, New Jersey 

Turnpike, Florida Turnpike, and Kansas Turnpike, a 

driver encountered a toll booth upon entry and 

exit. A paper ticket was provided on entry to record 

the start of the trip on the turnpike, and it was used 

upon exit to charge the driver for the distance driven on the road. 

Because of (a) the amount of space required for 

conventional toll booths in dense urban road networks, (b) the congestion caused by the need to 

slow down or to stop to pay, and (c) the associated 

negative public perceptions, this method is generally not considered appropriate for urban pricing. 

Automated payment machines have helped reduce 

the costs of manual collection.

One of, if not the only, manual-based congestion charge schemes in operation is the Durham 

City, United Kingdom (UK), scheme implemented in 2002, which uses a system of bollard gates 

and manual payment machines. Drivers are required to pay the designated charge when exiting 

the city center zone before the bollard gate will 

open. These gates are manned by an official, and 

drivers who are unable to pay are allowed to pass 

but incur a fine.

The street-based equipment required for a manual system includes charging booths, additional 

lanes to increase throughput, gates at all entry 

points, sufficient space to install the required equipment, and access to power and communications.

Sticker purchase machine.

Manual toll collection in 

Manual toll booth. Durham City, UK.
T e ch nologies Tha t E n a ble Congestion Pri c ing | 9

Image-Based Tolling/Automatic

License Plate Recognition (ALPR) 

Technology

ALPR technology is commonly used on most electronic tolling facilities around the world, both in 

free-flow and toll-lane-based situations, although 

most often it is used as an enforcement backup to 

dedicated short-range communications (DSRC) or 

vehicle-positioning system (VPS) technology. 

ALPR is based on images taken of vehicle license 

plates, which are then processed through optical 

character recognition software to identify the vehicle by its license plate. Some systems use front- and 

rear-located cameras to capture the images to improve identification rates. Once identified, the required charge or permit-checking processes are undertaken in a similar way to other systems.

A key issue with ALPR facilities is the level of 

reliability of the images. The best systems are capable of read rates of around 98 percent in good conditions, but this can be reduced as a result of light 

reflections in the image or dirty or damaged plates. 

This leads to the need for manual checking of those 

plates and can add significantly to processing costs.

The London Congestion Charge, an area-licensing scheme, is the only scheme that currently relies 

entirely on ALPR on a large scale as an enforcement 

system. Several other toll facilities provide ALPRonly account options to users, but most require additional administration fees to compensate for the 

increased cost of processing these types of transactions. The London scheme also requires ALPR stations within a designated zone, at fixed locations, 

and on mobile enforcement units. 

In the United States, most ALPR systems have 

been used on toll roads for payment violation enforcement, but this is changing. As toll facilities 

move to cashless open-road tolling, they are using 

ALPR systems as a tolling account rather than tags 

or DSRC transponders. Denver’s E-470 and Tampa’s Selmon Expressway are two examples where 

ALPR is used extensively to record the toll transaction. In Toronto’s 407 toll facility, drivers can use 

either tags or their license plate as identification for 

paying the toll. 

The roadside- or street-based equipment required for an ALPR system would include pole and/

or gantry-mounted cameras and illumination devices. In some cases, these are combined into one 

unit. Depending on the overall system design, there 

may be a requirement for additional cameras (front 

and rear), classification devices, and independent 

verification. In addition to the camera mountings, 

some form of system controller would be required 

near each installation, requiring full power and 

communication connections via a purpose-designed 

base unit connected to each camera location. Communications connections may need a dedicated or 

leased fiber-optic network, and the power supplies 

may need an uninterruptible power supply.

DSRC Free-Flow Toll Using 

Transponders and Gantries

DSRC is the most common form of primary electronic congestion-pricing technology in general use 

and is the standard on most free-flow toll facilities. 

The technology is based on on-board units (OBUs), 

sometimes referred to as tags or transponders, which 

Example of ALPR image.

Typical ALPR camera and illumination device.
10 | C o n g e s t i o n P r i c i n g

communicate with gantry-mounted equipment at 

checkpoints. The roadside equipment identifies and 

verifies each vehicle’s OBU, and depending on the 

type of system, either processes a charge from its 

designated account or confirms its rights of access. 

In most multi-lane free-flow systems, the DSRC 

system also acts to locate the vehicle within its detection zone by using an array of DSRC transceivers. Combinations of toll points can be used to facilitate distance-based charging systems, with 

special charging conditions for particular entry and 

exit points or times. The enforcement of this type 

of scheme is generally addressed by using roadside 

enforcement cameras and ALPR technology.

 DSRC tolling started in the United States at the 

North Dallas Toll Road. It became the harbinger for 

electronic toll collection (ETC) that has grown rapidly around the world. These early single-lane ETC 

facilities can still be found in New York City at the 

Port Authority of New York–New Jersey bridges and 

tunnels and on the San Francisco Bay area bridges 

and tunnels. Multiple lane, free-flow, or open road 

tolling (ORT), removed the toll booth and single 

lanes and combined ETC for two or more lanes at 

facilities in Oklahoma, Denver’s E-470, and most of 

the Orlando–Orange County expressway system. 

There is a range of DSRC systems in use and 

under development. Some use infrared communications; this technology has not been deployed 

widely in higher speed applications and is not generally considered as an open standard. Most are 

based on microwave communication. The most 

common systems currently in use are based on a 

5.8-GHz frequency, using the European CEN-278 

standard. This standard is now well developed and 

delivers robust and secure OBU devices with an average battery life of around 5 years. 

The next generation of 5.9-GHz systems, which 

are being developed mainly in the United States to 

address a wider spectrum of intelligent transportation systems (ITS) applications, will provide longer 

range communication and multiple channels. Although not currently in use on any operational pricing system, these OBUs are planned to become 

standard installations in all new vehicles within the 

next decade.

DSRC systems can be expanded relatively easily 

onto other routes or across adjacent areas through 

the deployment of additional toll or check points. 

However, expanding these types of systems to cover 

much wider areas is less cost-effective, because the 

numbers of toll points to provide effective coverage 

can increase significantly. 

The street-based facilities required for a DSRC 

system include a range of equipment, such as poleand/or gantry-mounted transceivers, ALPR cameras 

and illumination devices, vehicle-classification devices, independent verification devices, and roadside 

control cabinets.

 In the urban environment, some street layouts 

may require modifications to improve the operation of the system (e.g., to provide localized separation of traffic from opposing direction streams and 

to assist in reducing the need for full gantries in 

street situations). The transceiver/classifier units are 

generally mounted separately from the cameras to 

allow the cameras to detect vehicles in the pricing 

zone, although technologies are available to combine all functions at one location. A further variation in some arrangements is the use of front and 

rear cameras, which may require an additional camera support structure.

Some form of system controller would also be 

required in the vicinity of each installation, requiring full power and communication connections 

via a purpose-designed base unit connected to 

each location.
T e ch nologies Tha t E n a ble Congestion Pri c ing | 11

In multi-lane situations, an array of transceivers 

and classifiers will be required, generally mounted 

on purpose-built gantries or potentially mounted 

on existing structures. Where multi-lane facilities 

are to be installed in two directions, the relative location of gantries also requires consideration, because a degree of separation is required between 

some equipment.

Singapore operates an ETC system as its primary 

technology for congestion pricing. Groups (arrays) of 

transceivers mounted on entry-point gantries communicate with units in each vehicle to locate the vehicle and record the transaction. The OBUs are also 

equipped with smart card payment facilities.

In Italy, several major cities operate access control systems that use the TELEPASS toll system, 

which was developed and has been operating on 

the Italian motorway network. This system is based 

on the use of 5.8-GHz transceivers and OBUs and 

is designed for use in single-lane toll-gate situations only. 

VPS Technologies

Internationally, road authorities have been exploring and implementing VPS (e.g., global positioning 

system [GPS], Galileo, Global Navigation Satellite 

System [GLONASS]), which do not require onroad infrastructure to assign a position to a vehicle. 

Instead, these systems use satellite-location systems, 

generally GPS, to determine the vehicle’s position 

and to measure location and distance travelled for 

the purposes of charging and access control. These 

systems offer greater flexibility for authorities to 

vary charges to influence more aspects of travel and 

transportation choice. In Europe, the launch of the 

Galileo satellite system will complement the U.S. 

GPS system with over 30 more satellites in orbit, 

ensuring greater accuracy of position and location. 

The Russian GLONASS is currently being renovated and will add 30 more positioning satellites in 

orbit by 2015. In total, the fleet of positioning satellites, GPS, Galileo, and GLONASS will provide 

nearly 100 total satellites for positioning and navigation systems that will be accurate to less than 

3-feet positioning in the next 5 to 7 years. 

Although VPS technologies are an effective 

means of tracking vehicle position, the information 

they gather and store needs to be communicated to 

central systems on a regular basis, and as such, VPS 

units are generally combined with other technologies (e.g., digital maps, wide-area communications, 

and short-range general packet radio service [GPRS] 

communications) to charge and enforce the system. 

Additional features required include enforcement 

checkpoints (fixed and mobile) and depending on 

the focus of the system, these can be extensive. 

New DSRC systems such as the 5.9-GHz technology along with Wireless Fidelity (WiFi), Worldwide 

Interoperability for Microwave Access (WiMAX), 

and other third-generation communications capabilities that are being implemented in Baltimore 

and in other cities across the United States will 

make VPS more popular for navigation, tolling, and 

congestion pricing.

Components of Singapore’s ERP system. Example of vehicle positioning system.
12 | C o n g e s t i o n P r i c i n g

The current cost of units has been a major factor 

in these systems that are only being used for heavyvehicle application to date. Once established, VPSbased systems have the advantages of wide coverage and far fewer checkpoints than do other 

technologies. It is expected that on-board VPS 

units will become standard features in new vehicles 

within 10 years; this migration is a specifically identified strategy for the European Union. 

VPS-based systems require far less on-street 

equipment than do other systems, with the primary 

function of the street-based facilities being backup 

enforcement at selected checkpoints. Fixed on-street 

checkpoints are most likely to use DSRC and ALPR 

technologies that require a series of pole- or gantrymounted devices. These fixed enforcement stations 

will most likely be supported by mobile units that 

will reduce the number of locations required.

VPS-type technology is in use on several widearea, heavy-vehicle, road-user charging facilities, including systems in Germany and Switzerland. VPSbased systems have been introduced or considered 

(in the United Kingdom) as technology solutions for 

the introduction of distance-based charging, primarily for heavy vehicles. The German model is beginning to demonstrate that the technology is moving 

toward being “proven,” but only for a distance-based 

charge. 

Nowhere in the world has VPS been used for a 

more contained urban-congestion-pricing scheme, 

primarily because of difficulties in receiving signals 

from satellites in the urban environment (with its 

canyon effect) and because the higher costs of invehicle units are prohibitive in smaller areas. In an 

urban area, the costs of the scheme would also likely 

rise dramatically because of the need for “repeater” 

units to overcome the canyon effects and improve 

boundary accuracy. Similar systems have been used 

in Seattle for testing driver responses to tolling. Portland, Oregon, also ran a test with such a system in 

which drivers could pay the distance charge rather 

than pay a higher excise tax for fuel at the pump. The 

pilot test indicated that such a concept could act as a 

transition approach to moving away from fuel excise 

taxes to distance-based charges. 

Cellular Telephone and 

Pico-Cell Systems

A cellular network is basically a radio network made 

up of several radio cells, each served by a fixed 

transmitter that is known as a cell site or base station. These cells are used to provide radio coverage 

over a wider area. Cellular networks use a set of 

fixed main transceivers, each serving a cell and a set 

of distributed transceivers, which provide services 

to the network’s users. 

Pico-cell technology is, in simple terms, a more 

concentrated cell network that uses smaller transceivers and thus develops a cell network that provides a greater ability to locate mobile devices 

within the network. By using this type of network, 

it is possible to locate properly equipped vehicles 

with a high degree of accuracy, thus providing the 

potential to introduce distance-based charging 

by using a ground-based technology. The sensor 

networks being developed for this type of application consist of a large number of devices (known 

as motes) that are connected by using wireless 

technology. 

Recent trials in Maryland and California have 

involved the cellular network to gather traffic data 

based on a static network of motes connected to 

bus stops and mobile motes placed on buses, 

which become transient members of the static 

network as they approach a bus stop. The system 
T e ch nologies Tha t E n a ble Congestion Pri c ing | 13

trials have been used to provide position information collected from the buses. Future intelligent 

infrastructure pico-cell systems are based on the 

concept of a dense network of low-cost shortrange transceivers located within vehicles and on 

roadsides. 

Trials of this type of technology have recently 

been undertaken in the United Kingdom (Newcastle and London) to test the feasibility of this technology for congestion pricing. These trials have indicated that this type of technology does have the 

potential to provide a viable alternative to other 

location-based systems such as VPS.

The street-based equipment required for this 

type of system includes an extensive network of 

short-range communications devices that make up 

an integrated web of communications. These devices would be located in vehicles and as part of 

roadside infrastructure and would have minimal 

impact in terms of space or visual intrusion.

As with VPS-based systems, this type of system 

would require some on-street enforcement, although far less than other systems, with the primary function of the street-based facilities being 

backup enforcement at selected checkpoints. Fixed 

on-street checkpoints are most likely to use DSRC 

and ALPR technologies and require a series of poleor gantry-mounted devices. These fixed enforcement stations would most likely be supported by 

mobile units that would reduce the number of locations required.

Combination Systems

The majority of current pricing systems, including 

toll roads and urban charging and access schemes, 

use a combination of technologies to manage the 

collection and enforcement process. This includes 

almost all U.S. toll roads from Maine to Florida and 

from New York City to San Francisco. 

One of the most common combinations is the 

use of DSRC OBUs as the primary payment and 

identification technology and ALPR technology for 

enforcement and casual-user transactions. This 

combination allows operators to benefit from the 

higher accuracy and lower operating costs of DSRC, 

while using ALPR to overcome DSRC limitations 

of casual-user management and enforcement. This 

package also limits the use of the less accurate and 

more operations cost-hungry ALPR technology to a 

reduced number of transactions. 

Other global example combinations include the 

deployment of VPS on the German and Swiss truck 

toll systems, which use VPS to address the distanceand location-based elements; DSRC to provide the 

necessary local roadside communication; and ALPR 

as a base-enforcement technology.

Pico-cell data transmission illustration.
14 | C o n g e s t i o n P r i c i n g

Sub-System Technologies

As indicated in the Functional Processes for Tolling 

and Congestion Charging section of this primer, the 

tolling process is a combination of sub-processes 

that require close integration. The overall effectiveness of tolling and congestion-pricing technologies 

will be the aggregate improvement in all steps of 

the process for reliability and accuracy and minimized revenue leakage and fraud. There are several 

related sub-systems for which a range of technology 

options exist, which include the following:

•	 Informing and providing standard signs and lane

markings to increase driver recognition and understanding of the tolling or congestion pricing 

across the United States.

•	 Vehicle occupancy detection technologies.

•	 Vehicle identification and classification systems

(e.g., laser, video, digital loop, axle detection treadles, etc.).

•	 Telecommunications: Roadside and centralized

control equipment (e.g., in-unit, controller-based 

processing). 

•	 Automation of operations (e.g., payment and enforcement processing, account setup and management). 

•	 Payment systems for pre- and post-collection of

tolls or congestion-charging fees.

•	 Verification and secondary enforcement systems

(e.g., scene image capture, mobile and portable 

enforcement).

•	 System reliability and accuracy of DSRC systems.

•	 OBU distribution facilities. 

•	 ITS integration.

Informing and Providing 

Standardized Signs and 

Lane Markings

As tolling systems have grown across the United 

States, toll facilities have been very individual and 

unique enterprises. With the introduction of each 

facility and the advent of ETC, each of these facilities has developed its own branding of its ETC 

package. Today, a plethora of arcane and distinct 

brand names for ETC exist in the United States, 

including E-ZPass, FasTOLL, SunPass, MnPass, and 

a host of other names. In an age of standardization 

and interoperability, these names may confuse drivers who travel across the country. 

A similar situation existed in Sydney, Australia. 

Each toll road had its own brand name for its ETC. 

To solve the driver-recognition problem, a standard 

symbol of a green square with a yellow “E” was added to each toll lane and free-flow sign to indicate an 

interoperable ETC facility where any and all ETC 

transponders or OBUs could be read and accepted. 

With the advent of potential interoperable standards such as the vehicle infrastructure integration 

(VII) or 5.9-GHz technologies, a similar approach 

should be taken to mark all interoperable facilities 

across the United States. This would allow each toll 

facility to retain its branding for local recognition, 

but as it adopts a national interoperable standard, a 

common designation is necessary, as in Australia. 

Legally, each toll facility must be marked as a toll 

road to advise the user of the requirement for tolling. This is a common requirement across all toll 

facilities in the United States. Although this is a legal requirement, there are no standard road signs or 

lane markings for toll roads, priced lanes, or conges-
T e ch nologies Tha t E n a ble Congestion Pri c ing | 15

tion-pricing areas in the Manual on Uniform Traffic 

Control Devices (MUTCD) to integrate the efforts 

and provide a common set of signs, colors, and 

markings as toll roads, priced lanes, and congestion 

pricing grow in size and numbers across the United 

States. In the United Kingdom, for example, the red 

circle with a white “C” was originally developed for 

the London congestion charge. It appeared on all 

signs and lane markings to indicate to drivers the 

boundary of the congestion-charging zone in London and to provide information concerning the 

London congestion charge. 

In addition, color or road designation of these 

facilities—toll roads, priced lanes, and congestionpricing areas—should be designated for ease of map 

making and recognition. Just as we have standardized icons, colors, and signs for Interstates and highways, we need to develop these designations for 

tolling and congestion pricing. 

Vehicle-Occupancy 

Detection Technologies

A promising technological advancement that could 

improve congestion-pricing operations for pricedlane operations is the development of a more accurate vehicle-occupancy system. At present, some 

imaging software is able to read closed-captioned 

television (CCTV) images and discern the number 

of occupants. In addition, infrared sensors can detect human-heat signatures. Although more advanced algorithms and other advances in available 

technologies have made significant improvements 

in the software’s ability to identify human occupants, several inherent limitations prevent complete 

implementation of automated “outside the vehicle” 

occupancy monitoring. For example, sensors often 

have difficulty rendering data from all seats within 

a vehicle, particularly in the dark or when one of 

the passengers is a small child. Further complications arise in non-barrier-separated roads where 

movement between lanes has minimal physical restrictions. For automated enforcement to be implemented, sensors must achieve near perfect accuracy, 

which thus far has not been possible to attain.

One potential solution is to instead focus on occupancy monitoring from inside the vehicle. Seatbelt and air-bag sensors are already standard equipment on today’s vehicles, monitoring front-seat 

occupancy via mechanical seatbelt closure sensors 

and weight/pressure sensors installed within seats. 

In the future, additional sensors could be installed 

in the rear seat, allowing the vehicle to have a 

complete analysis of the number of occupants in 

the vehicle. Additional advanced sensors, including 

light-emitting diode (LED) and infrared imaging, 

could be added to ensure a more accurate measurement. The in-vehicle system could communicate occupancy information with sensors imbedded in the infrastructure via a radio transponder/

receiver system, GPS, or cellular signal to allow 

single-occupancy and high-occupancy vehicles using HOT lanes to be assessed the appropriate 

charges.

Vehicle-Identification and 

Classification Systems

The task of vehicle classification for congestion 

pricing varies with the type of scheme and primary 

technology used. For manual or semi-automated 

toll lanes, in which vehicles are confined to a single 

lane at reduced speed, classification can be measured by size, weight, or number of axles. In these 

situations, devices such as weigh-in-motion (WIM) 

detectors, treadles, or lasers can be used with relative accuracy.
16 | C o n g e s t i o n P r i c i n g

Once a free-flow environment is introduced and 

vehicles are required to be classified at full speed 

and in a multi-lane environment, the ability to classify with the use of technology is reduced, along 

with the range of technologies available. Current 

axle treadles and WIM technology do not provide 

sufficient accuracy to classify vehicles in this type of 

environment, and a size-based classification system 

is therefore required. 

There are currently two sufficiently reliable methods available to classify vehicles by size in a multilane free-flow environment: scanning-laser technology and stereoscopic-video technology. Digital loops 

also provide an option but are affected by lanechange movements and do not provide the range of 

classification available with laser and video systems.

The technologies for classification are another 

area in which standardization is needed across all 

toll facilities in the United States. A common reference system would assist drivers in knowing the 

charges they will incur. Current classification systems and their application create confusion and uncertainty in the minds of drivers. Only from a national perspective can this effort be directed and 

then implemented by states and toll agencies. 

Telecommunications: 

Roadside and Centralized 

Control Equipment

All congestion-pricing systems require the continuous processing of large volumes of transactions. Depending on the charging scheme and primary charging technology used, the complexities and volumes 

of these transactions can be managed in different 

ways to achieve a suitable balance between system 

reliability and operational cost.

One major area of consideration is the balance 

between roadside and centralized processing and 

the communications architecture developed to support these processes. Decisions should be based on 

several factors: 

•	 The volumes of data that need to be moved

around the system.

•	 The availability,reliability, and cost of communications.

•	 The number, security, and accessibility of roadside installations.

Congestion charging schemes rely on large volumes 

of transaction data passing between a network of 

roadside facilities and the back-office systems. Depending on the type and structure of the system, 

this data may be relatively low-volume, characterbased files, or much larger (for ALPR) digital-image 

files. These system requirements will have a significant influence on the architecture of the system 

and, in particular, the communications networks. 

For example, conducting ALPR processing at the 

roadside may significantly reduce communications 

and storage costs if the system provides for this type 

of operation; however, this requires a greater level 

of functionality within roadside equipment that 

may prove too costly to provide at a large number 

of locations.

These decisions and the resulting system architecture can have a major influence on the cost effectiveness of the entire system. For example, the 

London congestion charge is based on a high level 

of centralized processing with large volumes of data 

being transferred daily from many roadside facilities. This leads to higher costs, with recent technology reviews and trials highlighting the potential 

savings that could be made through a more efficient 

architecture. ALPR-based systems have the most to 

gain from improved architecture design, having the 

highest potential data requirements. DSRC systems 

Roadside processing equipment.

Centralized processing equipment. 
T e ch nologies Tha t E n a ble Congestion Pri c ing | 17

that use an ALPR enforcement component would 

be the next highest user, with VPS and cell systems 

most likely to have the lowest demand.

Recent trends in the development of the primary 

DSRC and ALPR equipment have led to the consolidation of some processing within these units, 

thus reducing the functions of roadside control 

units and further improving cost efficiency.

Automation of Operations

The major operational costs of congestion-pricing 

systems result from the continuous processing of 

large volumes of transactions. Depending on the 

charging scheme and primary charging technology 

used, these transactions and processes can be automated to reduce cost and improve the overall efficiency of the system. A key objective is to minimize 

manual processing, particularly where there is no 

direct customer contact.

The use of OBUs is a major contributor to reducing operational cost across most free-flow facilities. As the most reliable means of automating vehicle (or account holder) identification, this 

technology reduces the level of manual processing 

required and thus minimizes cost. 

Other areas of automation include account setup 

and management processes through interactive 

voice response (IVR) and the Internet, ordering of 

statements, and account top-up facilities. 

The selection of appropriate systems to automate back-office functions is critical to developing 

a cost-effective road-charging system. Congestion 

pricing is based on high-transaction volumes and 

relatively low-transaction values that lead to a focus 

on small costs to ensure a cost-efficient system. 

Payment Systems for Pre- and 

Post-Payment of Tolls and 

Charges

There is a wide range of payment options available, 

and the selection of an appropriate package of options needs to address the specific needs of each 

scheme. A key issue is the balance between providing security of payments at a reasonable cost and 

providing user convenience. 

Where manual or machine-based payment options are available, the use of cash and standard 

card-payment options is feasible, and although the 

management of cash payments involves some cost 

to the operator, the convenience and anonymity of 

cash addresses a key concern of some users. 

For most electronic tolling and congestion-pricing 

systems, the primary and preferred payment mechanism is through customer accounts. These provide 

greater security of payment for the operator (as users are generally required to prepay and provide 

bank account or credit card details) and reduce the 

cost of operation. Accounts are also more convenient for most users, because they are not required 

to make individual payments for each transaction. 

Account-based payments can be used with any 

OBU or ALPR-based system and are the most common form of payment for free-flow toll facilities.

A further option is the use of smartcards, as used 

in the Singapore ERP system. These cards are used 

with the vehicle’s OBU, and payment is debited 

from the card balance. This provides a further level 

of convenience that is preferred by some customers, 

and as the balance on the card is prepaid, there is a 

degree of security for the operator. The main disadvantages are the increased complexity and cost of 

the OBU and the need to provide real-time roadside processing of payments. 

One advanced electronic-payment technology 

with potential application in congestion-pricing 

programs involves the use of contactless bank cards. 

Back-office operations. Contactless smart bank cards, such as the Visa Wave 
18 | C o n g e s t i o n P r i c i n g

ALPR enforcement. 

or the MasterCard PayPass, are being distributed by 

several U.S. banks already, and more plan to follow. 

These cards allow payment by radio frequency 

identification (RFID) transaction—just tapping the 

card on the reader—instead of requiring the magnetic stripe of the card to be run trough the reader 

(a slow and fraud-prone process). EMV is a protocol, developed by Europay, MasterCard, and Visa 

(EMV), for authenticating credit and debit card 

payments at point-of-service (POS) terminals and 

automated teller machines (ATMs) through the use 

of interoperable chips. 

Although it has failed to gain traction in the 

United States, this standard is used throughout 

most of the world, including Europe and Asia. The 

version of EMV used on the contactless bank cards, 

called contactless EMV, uses an encryption algorithm that makes them essentially fraud proof. In 

congestion-pricing programs, the contactless EMV 

cards could be used in OBUs that act as the toll-tag 

transponder. OBUs with contact smartcard card 

readers are in use in Singapore, and the Norwegian 

company Q-Free built OBUs with contactless card 

readers that were used at the 2006 Winter Olympics in Turin, Italy. By using such transponders and 

cards, congestion-pricing programs could avoid having individual user accounts to administer—users 

would pay directly by bank card. 

Secondary Enforcement

ALPR is effectively the foundation of all electronic 

free-flow charging, because it is the only common 

point of reference for all vehicles passing through a 

toll checkpoint or zone boundary.

In most free-flow tolling applications, ALPR is 

used only as an enforcement tool, with the majority 

of users charged and verified through an OBU. Even 

in this situation, secondary enforcement systems, 

such as color-scene images, are recorded for evidence and to back up the basic ALPR records. 

However, in situations in which either ALPR is 

the primary technology or there is a need for further enforcement backup, other backup systems 

and technologies can be used, such as front and rear 

ALPR systems or digital video recording of traffic 

that can be accessed later to assist in identifying offending vehicles. These systems can provide an alternative view of traffic from the primary ALPR 

systems and can overcome adverse environmental 

conditions such as sunlight or shadow effects.

System Reliability and 

Accuracy of DSRC Systems

Pricing systems using vehicle-based OBUs are used 

widely across the world for a range of tolling and 

road-charging applications. These systems generally 

use a microwave signal at or around 5.8 GHz to 

provide the critical vehicle-to-roadside communication function. The most widely used standard for 

this frequency range is the European CEN-278 

standard. 

As the planned role for vehicle-to-roadside and 

vehicle-to-vehicle communications becomes more 

widespread (i.e., moving into dedicated safety systems, traveler information, and other ITS applica-
T e ch nologies Tha t E n a ble Congestion Pri c ing | 19

tions), the 5.8-GHz standard is being superseded 

by a standard in the range of 5.850–5.925 GHz. 

This developing standard, known as WAVE, has 

greater range and greater multi-channel capability. 

Although there are no current road-charging applications in operation, it is likely that this standard 

will replace and enhance current systems over the 

next 10 years or so.

In the United States, the implementation of 

DSRC-enabled devices serves as part of the VII initiative, which brings together vehicle manufacturers, government agencies, and professional organizations in the design of architecture, standards, 

policies, and potential business models of a system 

that will enable vehicles to communicate with each 

other and roadside equipment. It is envisioned that 

VII transponders will be installed soon in all vehicles and that roadside equipment will be deployed 

at major intersections and along roadways throughout the nation to form a nationwide network. Applications for VII include public safety, traveler information, and demand management. The vision 

for VII is to deploy roadside units throughout the 

country, thus creating a uniform, nationwide data 

network. Combined with GPS, all connected vehicles will know their location and have the ability to 

communicate location, traffic conditions, and other 

information to the system. The ability to exchange 

such information could be useful in congestion 

pricing. 

OBU Distribution Facilities

The distribution and management of OBUs for 

DSRC and VPS-based systems incorporate a range 

of technologies and systems designed to address the 

specific requirements of particular schemes. The 

majority of OBUs would be distributed from a central facility by mail, by customer collection, or 

through agent networks. However, the use of vending machines has helped improve distribution and 

availability, as is the case with the Austrian Motorway toll system. 

Banks and financial institutions also distribute 

tags, OBUs, and transponders. For example, in Spain 

and southern France, the VIA-T project proved that 

drivers could sign up for toll accounts through 

banks and financial institutions. These institutions 

provide the OBUs and the account mechanism for 

drivers by linking payments to (a) the bank-issued 

credit card, (b) a person’s checking account (direct 

payment), or (c) a savings account/debit account. 

Just like the issuance of a credit card, the OBU was 

dispatched from a central depository to the individual by express and registered mail. 

As toll roads, priced lanes, and congestion pricing 

become more common, the business model for 

standardized OBUs should change, as well as the 

business model that people use to secure them. 

ITS Integration

The level and type of ITS integration will depend 

on the type of pricing system adopted and the payment structures and technologies used, but opportunities exist to integrate at many levels. Another 

major area of ITS integration is the use of pricingsystem data to provide travel time and congestion 

information. One of the best-developed systems is 

the Italian TELEPASS system that has been in operation on the motorway network for many years. 

The large numbers of OBUs continually moving 

across the motorway network are tracked by purpose-designed stations to provide real-time traveltime information, linked into traveler information 

systems.
20 | C o n g e s t i o n P r i c i n g

ALPR—Automatic License Plate Recognition. Software that enables authorities to match the vehicle 

license plate with identity information in registration 

data.

ALS—Area Licensing Scheme. Singapore’s ALS, operated from 1975 until 1998, required car drivers 

entering the CBD during the morning peak to pay 

three Singapore dollars per day (with exemptions for 

vehicles carrying four or more people).

ATM—Automated Teller Machine. A computerized 

telecommunications device that provides the customers of a financial institution with access to financial transactions without the need for a human clerk 

or bank teller. 

CCTV—Closed-Circuit Television. The use of video 

cameras to transmit a signal to a specific place, such 

as a limited set of monitors. 

CBD—Central Business District. The commercial 

and often geographic heart of a city. 

CEN—European Committee for Standardization. 

The CEN was founded in 1961 by the national standards bodies in the European Economic Community 

and European Free Trade Association countries. CEN 

contributes to the objectives of the European Union 

and European Economic Area with voluntary technical standards, which promote free trade, the safety 

of workers and consumers, interoperability of networks, environmental protection, exploitation of research and development programs, and public procurement.

DSRC—Dedicated Short-Range Communications. 

A short- to medium-range communications service 

that supports both public safety and private operations in roadside-to-vehicle and vehicle-to-vehicle 

communication environments.

EMV—Europay, MasterCard, and Visa.

ERP—Electronic Road Pricing. Electronic toll-collection system that prices roads based on usage.

ETC—Electronic Toll Collection. The collection of 

tolls based on the automatic identification and classification of vehicles by using electronic systems that 

do not require drivers to stop or slow down.

GHz—Gigahertz. A unit of alternating current (AC) 

or electromagnetic (EM) wave frequency equal to 

one thousand million Hertz (1,000,000,000 Hz). 

The gigahertz is used as an indicator of the frequency 

of ultra-high-frequency and microwave EM signals. 

GLONASS—Global Navigation Satellite System. 

Based on a constellation of active satellites that continuously transmit coded signals in two frequency 

bands, which can be received by users anywhere on 

the earth’s surface to identify their position and velocity in real time based on ranging measurements. 

The system is a counterpart to the United States’ 

global positioning system (GPS), and both systems 

share the same principles in the data transmission 

and positioning methods. GLONASS is managed for 

the Russian Federation Government by the Russian 

Space Forces, and the system is operated by the Coordination Scientific Information Center (KNITs) of 

the Ministry of Defense of the Russian Federation.

Acronym List/Glossary
T e ch nologies Tha t E n a ble Congestion Pri c ing | 21

GPS—Global Positioning System. A U.S. spacebased radio-navigation system that provides reliable 

positioning, navigation, and timing services to civilian users on a continuous worldwide basis—freely 

available to all. For anyone with a GPS receiver, the 

system will provide location and time.

GPRS—General Packet Radio Service. A packetoriented mobile data service available to users of 

Global System for Mobile Communications.

HCV—Heavy Commercial Vehicles. Includes all 

heavy motor vehicles used for the transportation of 

passengers for hire, or constructed or used for transportation of goods, wares, or merchandise.

HOT—High-Occupancy Toll. On HOT lanes, lowoccupancy vehicles are charged a toll, whereas highoccupancy vehicles are allowed to use the lanes free 

or at a discounted toll rate. 

HOV—High-Occupancy Vehicle. Highway lanes 

are typically reserved for these vehicles with two or 

more occupants.

ITS—Intelligent Transportation Systems. An electronic toll-collection system without toll plazas, 

where all drivers are charged the toll without stopping, slowing down, or being in a specific lane.

IVR—Interactive Voice Response. A phone technology that allows a computer to detect voice and touch 

tones using a normal phone call.

LED—Light-Emitting Diode. A semiconducter diode that emits light when an electric current is applied. 

MUTCD—Manual on Uniform Traffic Control Devices. Defines the standards used by road managers 

nationwide to install and maintain traffic control devices on all streets and highways. The MUTCD is 

published by the Federal Highway Administration. 

OBU—On-Board Unit. Also called an on-board 

transponder. The in-vehicle device component of an 

ETC system. A receiver or transceiver permitting the 

Operator’s Roadside Unit to communicate with, 

identify, and conduct an electronic-toll transaction.

ORT—Open Road Tolling. An electronic toll-collection system without toll plazas, where all drivers 

are charged the toll without stopping, slowing down, 

or being in a specific lane.

POS—Point of Service (or Sale). A retail shop, a 

checkout counter, or the location where a transaction occurs. 

RF—Radio Frequency.

RFID—Radio Frequency Identification. A technology similar to bar-code technology. With RFID, the 

electromagnetic or electrostatic coupling in the RF 

portion of the electromagnetic spectrum is used to 

transmit signals. An RFID system consists of an antenna and a transceiver, which read the radio frequency and transfer the information to a processing 

device and a transponder, or tag, which is an integrated circuit containing the RF circuitry and information to be transmitted.

RUC—Road-User Charging. A mechanism through 

which motorists pay to use a defined area of road, 

usually through payment of a toll.

U.K.—United Kingdom. The United Kingdom is a 

state consisting of four countries: England, Northern 

Ireland, Scotland, and Wales. 

UPS—Uninterruptible Power Supply. A device that 

maintains a continuous supply of electric power to 

connected equipment by supplying power from a 

separate source.

U.S.—United States. A constitutional republic consisting of 50 states and 1 federal district.

VII—Vehicle Infrastructure Integration. VII will 

work toward the deployment of advanced vehicle–

vehicle and vehicle–infrastructure communications 

that could keep vehicles from leaving the road and 

enhance their safe movement through intersections.
22 | C o n g e s t i o n P r i c i n g

VPS—Vehicle Positioning System. Satellite-based 

system for vehicle tracking and positioning.

WAVE—Wireless Access in Vehicular Environments. Wireless communications that will let motor 

vehicles interact with roadside systems to access 

safety information and travel-related services, even at 

high speeds.

WiFi—Wireless Fidelity. A term for certain types of 

wireless local area networks that use specifications in 

the 802.11 family.

WIM—Weigh in Motion. Devices designed to capture and record truck axle weights and gross vehicle 

weights as the trucks drive over a sensor.

WiMAX—Worldwide Interoperability for Microwave Access. A telecommunications technology that 

provides for the wireless transmission of data by 

using a variety of transmission modes, from point-topoint links to full mobile-cellular-type access.
T e ch nologies Tha t E n a ble Congestion Pri c ing | 23

1. San Diego Association of Governments. (2008). FasTrak®. Retrieved on November 10, 

2008, from http://fastrak.511sd.com/

2. New Zealand Ministry of Transportation. (2005). Auckland Road Pricing Evaluation Study, 

Final Report. Retrieved on November 10, 2008, from http://www.transport.govt.nz/

arpes-index/

3. Singapore Land Transportation Authority. (2008). Retrieved November 10, 2008, from 

http://www.lta.gov.sg/

4. Hong Kong Transportation Department. (2001). Feasibility Study on Electronic Road 

Pricing: Final Report. Retrieved November 10, 2008, from http://www.td.gov.hk/

publications_and_press_releases/publications/free_publications/feasibility_study_

on_electronic_road_pricing_final/index.htm

References

For more information, contact: 

Jimmy Chu

Office of Transportation Management, HOTM

Federal Highway Administration

U.S. Department of Transportation

1200 New Jersey Avenue, S.E.

Washington, DC 20590

Tel: 202-366-3379

E-mail: jimmy.chu@dot.gov
ii | C o n g e s t i o n P r i c i n g

Office of Transportation Management

Federal Highway Administration

U.S. Department of Transportation

1200 New Jersey Avenue, S.E.

Washington, DC 20590

Tel: 202-366-6726

www.ops.fhwa.dot.gov/siteindex.htm

October 2008

FHWA-HOP-08-042