Smart mobility and congestion charging

By LT Division

Application of smart mobility to congestion management

Today, 55% of the world’s population lives in urban areas. This figure is expected to increase to 68% by 2050¹. Numerous social challenges arise from the ever-increasing demand for personal mobility and its impact on space and the environment. Most urban centres have crowded transportation networks, in which any small disruption can easily cause long traffic jams. Moreover, urbanised transportation systems emit pollutants that threaten habitability and increase global warming. Over the last few decades, a wide variety of traffic management and control measures have been developed for urban traffic control (eg parking controls, one-way street systems, CCTV traffic surveillance and computerised area-traffic-signal control systems), but serious traffic problems remain.

Smart mobility is the concept of solving the challenges of commuting, traffic and transportation by developing systems that provide safe, informative, green, mobile and accessible transportation for today and the future². The rapid growth and development of information and communication technology have spurred numerous smart mobility solutions for traffic congestion, including ride-sharing, car-sharing, mobility-as-a-service, autonomous vehicles and real time mobility applications. One such solution that has been put into practice is the pricing mechanism of congestion charging, which is now widely considered as an effective traffic management measure to relieve urban congestion in many metropolitan cities. Congestion charging acts as a stimulus to enhance public transportation and therefore has economic, social and environmental benefits to the local community. Unfortunately, over time, many of these charging schemes have been unable to sustain all of the outcomes initially claimed. In many cases, the authorities have had to make compromises to appease the local community, or modify the solution by applying concessions to achieve the required level of ongoing political acceptance.

Congestion charging systems around the world

The theory of traffic congestion charging was first proposed by A C Pigou³ and F H Knight⁴. Over the last few decades, various forms of congestion charging systems have come into operation in a number of overseas metropolitan cities. Early successes in Singapore (1975) and London (2003) inspired transportation planners in other areas to introduce congestion charging systems, eg in Durham, the United Kingdom (2002); Dubai, United Arab Emirates (2007); Valletta, Malta (2007); Stockholm, Sweden (2007); Milan, Italy (2012); and Gothenburg, Sweden (2013).

(a) Singapore

The first road pricing scheme in Singapore, known as the Area Licensing Scheme (ALS), operated from 1975 to 1998 and used short-range communications (DSRC) channels. The scheme covered an approximately 6 sq km area of the most trafficcongested region. 28 gantries were set up at points along the boundary of the restricted zone (RZ) of the Central Business District (CBD). Vehicles entering this region during the peak time interval from Monday to Friday were controlled. After the enforcement of the ALS, the number of vehicles entering the CBD during the restricted hours dropped from 42,790 in March 1975 to an average of 11,363 in September and October 1975, an impressive 73% reduction^5,6. The ALS was the first urban traffic congestion pricing scheme to be successfully implemented anywhere in the world. In September 1998, it was replaced by the current Electronic Road Pricing (ERP) scheme.

Singapore’s ERP gantry

The ERP scheme consists of gantries located on all roads linking to Singapore’s CBD and the city’s expressways. Vehicles are loaded with an immediate-payment smart card using an in-vehicle unit (IVU). The effect on both charge collection and traffic flow adjustment has been remarkable: a traffic reduction of about 13% was recorded during ERP operational hours after implementation⁷. Taking advantage of technological progress, a new global navigation satellite system (GNSS) based ERP system is planned to be launched in late 2020 to develop additional value-added services for drivers in Singapore.

(b) London

As early as 1991, London began to study the feasibility of road congestion charging. The London Congestion Charge was first introduced by Transport for London (TfL) in February 2003, and extended westwards in 2007. However, the Western Extension was fully removed from the charging zone in December 2010^8,9. Despite this, the Congestion Charge Zone in central London is still one of the largest such zones in the world. Charging is applied from 7:00am to 6:00pm, Monday to Friday. The congestion charge has reduced several of the most serious traffic-related issues that London had been facing, and has improved the transportation service, air quality and road safety. Evidence from TfL suggests that following the introduction of the congestion charge, traffic entering the original charging zone has remained stable at 27% lower than in 2002. In addition, the environmental benefits have been remarkable, with a reduction of over 10% in the emission of toxic gases responsible for premature deaths^9,10.

The Congestion Charge Zone in Central London

Through careful selection from a wide range of scheme design options, congestion charging systems can be harnessed to serve numerous other policy aims, such as reducing congestion and optimising transportation, improving air quality, reducing pollution, generating revenue, promoting modal shifts in transportation, and improving quality of life and road safety. Indeed, various forms of congestion charging systems are now in operation in many metropolitan cities. The Durham Road User Charge, introduced in 2002, was the first congestion charge scheme in the United Kingdom, one year before London. The Durham scheme brought about tangible traffic benefits to the charging area. Traffic volume dropped by 85% and pedestrian activity increased by 10% in 2003. The revenue was used to support a frequent bus service to and from the charging area¹¹. Likewise, upon the implementation of a congestion tax in Stockholm, Sweden on 1 August 2007, the number of private vehicles entering the charging areas decreased by 29%. In Valletta, Malta, peak hour traffic dropped by 60% in long car stays following the introduction of congestion charging¹². In 2012, the Area C scheme in Milan successfully mitigated traffic jams in the city’s central section, with a nearly 30% reduction in vehicles entering the RZ in 2015¹³. The Milan scheme brought about both traffic and environmental benefits to the charging area and the revenue was re-invested in the city’s sustainable mobility scheme. In the United States, New York City will be the first city to impose congestion pricing. A traffic congestion fee will come into effect by 2021 in Manhattan’s CBD.

Hong Kong’s situation

Hong Kong is well known as a leading logistics, transportation and financial hub for business in the Asia-Pacific Region. Despite its world-class public transportation system, in which mass transit caters for some 90% of commuters every day, Hong Kong still suffers serious traffic congestion in many districts. Apart from district-wide traffic congestion problems, there are several major bottlenecks in strategic highways, such as Tuen Mun Road, Fanling Highway, Tai Po Road, the Cross Harbour Tunnel and Eastern Harbour Crossing. Unfortunately, car licensing figures show that over the last ten years since 2010, the number of private cars in Hong Kong has increased by 38%, with an average annual increase of 3.7%¹⁴. There are about 347 licensed vehicles for every kilometer of road, but the topography makes it increasingly difficult to provide additional road capacity in heavily built-up areas¹⁵. In consequence, road traffic congestion is deteriorating in Hong Kong. The worsening traffic congestion has exacerbated vehicle emissions and adversely affected the local air quality, giving added urgency to the need to tackle traffic congestion.

To promote livability in Hong Kong, the HKSAR Government is committed to progressively deploying technology to enhance traffic management in a systematic and well-planned manner, with the particular aim of alleviating traffic congestion, which is one of the initiatives under the Smart Mobility Roadmap². The “user pays” principle of ERP has been investigated in Hong Kong several times and found to be potentially capable of reducing peak traffic volume and relieving traffic congestion, and hence minimising vehicle emissions. The first Hong Kong ERP Pilot Scheme was conducted between 1983 and 1985 to tackle road congestion in the urban area. The pilot scheme was feasible on technical, administrative and legal grounds, and delivered positive results. However, public opposition stalled the permanent implementation of ERP. In the early 1990s, a sharp increase in the number of private vehicles prompted a community-wide discussion of how to control car growth and address traffic congestion. The Government hence commissioned a feasibility study with the objective of examining the practicability of implementing an ERP system in Hong Kong to reaffirm the technical feasibility of ERP based on experience in Singapore and Europe.

Hong Kong urged to relieve the rush hour traffic in the CBD

In view of the particularly congested traffic situation of the CBD in the Central and adjacent areas, the Government launched a three-month public engagement activity in the ERP Pilot Scheme in 2015. An International Expert Panel comprising members from the United Kingdom, the United States, Singapore and Sweden, as well as Hong Kong, has been set up to help the Government take forward the ERP Pilot Scheme. The basic elements and pertinent issues of the ERP Pilot Scheme, including charging area, payment mechanism, hours of operation, pricing level, exemptions and concessions, technology, effectiveness, complementary measures and privacy concerns, are now under review¹⁶.

Advanced congestion charging technologies

To facilitate the implementation of congestion charging systems, various technologies have been developed. Primarily, the choice of technology is often related to accuracy, cost, reliability, privacy and user friendliness. A congestion charging system should provide a free-flow detection and identification system with high accuracy. This is typically done using equipment installed on above-road gantries. Vehicles are usually detected using either laser or video technology, and identified through either license plate recognition or a transponder, an IVU that communicates with the equipment in the gantries.

(a) Automatic number plate recognition

Automatic number plate recognition (ANPR) is a common vehicle identification technology that operates in all congestion charging systems for either identification or enforcement purposes. Using optical character recognition, it enables a computer system to read vehicle registration plates automatically from digital images. Surveillance cameras on ERP poles or gantries are normally installed within and at entrances and exits to the charging areas. For example, ANPR technology is deployed in the London congestion charging scheme. The charging is enforced by 400 cameras situated throughout the congestion charging zone. Cameras record images of traffic and send them to a central processor to have their number plates read and checked against the list of vehicles that have been paid for. TfL has reported a 90% accuracy rate for number plate recognition, a figure that rises as a vehicle passes more camera positions^{17, 18}. As this automated process is not usually successful for 100% of license plates, additional manual verification/validation is often needed.

Automatic number plate recognition in Europe

(b) Dedicated short-range communication and radio frequency identification

Besides fixed ANPR cameras, alternatives include DSRC readers mounted on roadside gantries or poles, which are used to identify IVUs installed in passing vehicles. When a vehicle equipped with an IVU passes under an ERP gantry, the transponder’s information is read by the roadside equipment via a DSRC system. A road usage charge is then deducted from the stored-value card in the IVU. In general, there are two payment modes for ERP charges: (1) front-end payments, where a prepaid smart card that is placed in the IVU is automatically debited (eg Singapore), and (2) back-end payment, in which the identification details are sent to the back office, where a charge is calculated and an account is debited.

Similar to DSRC systems, radio frequency identification (RFID) sticker tags embedded with a unique identifier are commonly installed inside the windscreen or outside a headlamp of thevehicle to communicate with the roadside equipment. The key benefit of DSRC and RFID over ANPR-based technological solutions is the improved efficiency of automated identification, which reduces operational costs. The reliability of RFID and DSRC applications often reaches nearly 100%¹⁹ .

(c) GNSS

The next generation of ERP systems will use new wireless communication technologies such as GNSS, and provide additional value-added services to enhance the overall travel experience. This system uses distance measurements from satellites to identify the location of the vehicle, allowing the correct charge to be assessed. Accuracy is relatively high, as GNSS systems are able to calculate the time and location of a vehicle to within a few meters. However, installation of roadside location service devices coupled with surveillance cameras is needed to improve the accuracy of the system. The main advantage of GNSS-based systems is the flexibility they offer for charging regimes, as they allow the existing charging policy to be easily adjusted. In principle, the pricing policy is implemented completely through software instead of roadside equipment and thus new roads can be added, removed, and changed on a daily basis if necessary. GNSS also enables distance-based charging policies, which are theoretically attractive. However, GNSS-based systems are expensive, as the cost of the on-board unit is typically 10 - 20 times that of a tag-based solution. The cost of operation is also usually higher as software needs to be maintained and updates need to be distributed. Solutions are under development and the cost issue is becoming less prohibitive, but it is not yet completely resolved.

GNSS-based technology is now being planned for implementation in Singapore by late 2020. The satellite tolling technique enables real time traffic information, allows e-payment for checkpoint tolls and automatic charging of off-peak cars. It also introduces paperless coupon parking irrespective of whether a vehicle is within a restricted cordon area or not.

New wireless communication technologies for our future transportation system

Planning and implementation o congestion charging schemes

Every road has some limits to its capacity. In this respect, imposing a congestion charge on every driver could be an effective traffic management measure to relieve urban congestion during peak hours. Moreover, the income from these congestion charges can be used to improve public transportation or invest in highway infrastructure. An enormous amount of research into congestion charging has accompanied its increasing popularity around the world.

However, introducing congestion charging is a complex and controversial matter. A recurring argument against congestion charging is the equity concern that it disproportionately affects people on lower incomes. Following its implementation, a frequent complaint is that the charges are too high and exemptions or discounts should be applied to certain groups. However, it is possible to objectively determine appropriate charge levels based on transportation model forecasts in the policy design process. Furthermore, revenue can be allocated to offset the equity effects of congestion charging for low-income drivers. Beyond the equity problem, privacy concerns are another issue that typically receive significant consideration in policy development processes. In fact, identification of persons or vehicle owners is in principle only necessary where violations occur (for example, non-payment). In London, enforcement  cameras are calibrated to avoid capturing the faces of drivers. In Singapore, where congestion charges can be paid with an anonymous prepaid smart card, the system is set to only record the number plate in case of a failure in payment. For distance-based charging using GNSS-based technologies, a common belief among the public is that vehicles need to be tracked in real time, but even here much of the privacy can be maintained by coding the charging algorithm into the vehicle’s software and only reporting fee data to the back office.

Of course, the development of a congestion charging policy is not straightforward, and building public acceptance is essential to successfully introduce congestion pricing. Depending on individual political beliefs, acceptance may either increase or decrease, and vary over time. When congestion charging is first introduced as a concept to solve traffic congestion and environmental problems, public attitudes generally hold that the policy is beneficial. As soon as details of the policy become known, however, and opposers initiate their campaigns, acceptance levels tend to decline. Just prior to introduction, acceptance levels will be at their lowest. As soon as congestion charging policies become active and the desired effects are actually achieved, however, public acceptance of the system rises again. Most congestion charging schemes have had to withstand at least some public criticism, but one lesson learned from other cities is that congestion charging is more acceptable to the public if they are consulted and engaged throughout the process. Moreover, as people accumulate more experience of congestion charging schemes, their level of acceptance tends to rise, as they understand the costs and benefits.

Urban population growth is straining transportation networks in many metropolitan cities, including Hong Kong. The concept of smart mobility has become a focus of public attention as an answer to the emerging needs and challenges of urban areas. There is a wide spectrum of strategies that cities can adopt to become smarter, but decisions are often the result of important trade-offs and the formulation of the right balance between equity, privacy, and public acceptance with due consideration to the cultural and travel characteristics of the cities. Although there is no single solution, congestion charging is still believed to be one of the most effective smart mobility measures to relieve urban traffic congestion.

References
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This article was prepared by Ir Charles H T So and Ir Dr Y C Li from the LT Division.