Many existing infrastructure assets suffer from congestion because demand has risen well beyond the level forecasted. Since their capacity is limited, and it might not be feasible to build new assets, it is essential for governments to make the most of their installed asset capacity. Even a slight increase in effective throughput can make a large difference, since congestion is a strongly non-linear phenomenon.

Increasing throughput of existing assets has enormous societal value. Once the large, upfront sunk investments for building an infrastructure asset have been made, each additional user will incur only low marginal costs, but that usage will translate into greater user benefits and/or revenues – and thus contribute to pay off the initial investment.

Figure 11: Overview of Asset Utilization Strategies

 

To alleviate congestion and maximize asset utilization, operators should pursue a three-part best practice strategy: enhance peak capacity and effective throughput; apply demand management to reduce peak demand by shifting some of it off-peak; and optimize availability and reduce downtime (Figure 11).

Enhance peak capacity and effective throughput 

Enhance peak capacity by unlocking backup capacity.

Infrastructure assets often have embedded additional or reserve capacity that is not being used. Once made available, it can ease bottlenecks dramatically. Some examples:

• The hard shoulder or emergency lane on highways: by opening these to traffic during rush hours, or in dynamic response to heavy traffic, authorities can greatly reduce traffic jams. Using this approach, the Italian highway system at Bologna has cut total user time lost by almost 75%, while also reducing accidents by 18% and injuries and deaths by about 35%.⁴²
• Reversible lanes on highways: when necessary, certain stretches of a highway can be designated for traffic going in either direction. Hong Kong’s busy Route 8 highway, for instance, applies a real-time mix of lane assignment management.⁴³
• Underexploited power transmission lines: real-time ratings, based on a continuous monitoring of mechanical tension and temperature, tend to yield higher capacity than static ratings (which are based on conservative assumptions such as high ambient temperature and high solar radiation). This allows operators to harness existing, untapped transmission capacity and thus resolve line congestion problems. The McCarney-to-Big Lake line in Texas, for instance, was able to increase its capacity by 10-15% through real-time ratings, thereby accommodating the increase in wind farms and cancelling a planned US$ 20 million line upgrade.⁴⁴

Obviously, such backup capacity techniques have their risks (safety lapses, increased stress, wear on the system), which need to be carefully managed.

Enhance peak capacity by targeted capacity enhancement.

A system operates only as effectively as its weakest component. So a cost-effective approach to enhancing capacity is to conduct a systemwide analysis to identify bottlenecks, and then make targeted and incremental investments using existing infrastructure and/or rights-of-way, rather than undertaking major construction work. Some examples:

•  Airports: London City Airport (UK) took a coordinated, capacity-boosting initiative across the system, from landside (four additional security lines, a larger departure lounge, self-service kiosks) to apron (four new aircraft stands for larger aircraft, a new runway link and connecting pier) and airside (closer cooperation with air traffic control to optimize slot availability). The result was an increase in capacity from 32 to 38 air traffic movements per hour.⁴⁵
• Roads: various debottlenecking techniques have been used, such as adding extra lanes in upslopes in hilly terrain, and free flow tolling to maximize capacity at typical choke points. 
• Water treatment: for example, the As-Samra plant in Jordan, when overloaded owing to pollution, made a limited but targeted investment in additional centrifuge presses and gravity belt thickeners to remove the bottleneck in the treatment process.

A related approach is to dynamically adjust resources to prevent congestion at bottlenecks. Frankfurt Airport, for instance, introduced an integrated system of real-time, passenger flow forecasting and resource planning. The system simulates passenger flows, identifies upcoming bottlenecks, provides continuous updates to the Terminal Operations Centre and dynamically adjusts the required staff. The system increased peak terminal capacity from 150,000 to 200,000 passengers per day, reducing passenger waiting times by 20%, and also reduced resource planning from five days to only a few hours.⁴⁶

Enhance peak capacity by enabling and encouraging users to optimally use capacity.

A system’s capacity is determined not only by the infrastructure asset’s design and operation, but also by the users (e.g. cars, aircraft, ships). While infrastructure operators have no direct influence over that aspect of capacity, they can enable and encourage users to use the system capacity to the fullest extent possible. 

• Enable high-capacity usage via structural measures: many airports, for example, have constructed new gates to accommodate larger aircraft such as the Airbus A380. To encourage carpooling, Vinci Autoroutes in France created 1,000 dedicated parking places near toll gates,⁴⁷ and many US highways have introduced special managed or high-occupancy vehicle lanes.
• Encourage high-capacity usage through pricing: For instance, Heathrow Airport (UK), limited to two runways while other major European airports with similar passenger numbers have three to four, charges small aircraft relatively higher fees to motivate carriers to use larger, high-capacity aircraft. And on US highways, high-occupancy toll (HOT) lanes create incentives for carpooling by waiving charges for multi-passenger cars.

In addition to increasing peak capacity, asset utilization can be boosted by increasing effective throughput.

Increase effective throughput by reducing headways and technical losses.

An asset’s theoretical peak capacity seldom translates into actual realized capacity, owing to the system’s complexity and dynamics. User interactions are too unpredictable, and system interfaces can never be perfectly managed. Such losses are unavoidable; for example, water tends to drain away through cracks in the piping, and traffic flow is interrupted by erratic driving behaviour. The search for parking places can account for as much as 30% of inner-city traffic,⁴⁸ and suboptimal timing of traffic lights on US roads accounts for an estimated 10% of delays.⁴⁹ The two broad measures for increasing throughput are to reduce headways (in transportation) and to reduce technical losses (in utility operations).

Figure 12: Examples of Headway Reduction Strategies

 

Sources: “Active Traffic Management. Monitoring and Evaluation Project Results and future work”. UK Highways Agency, http://www.easyway-its.eu/download/392/1172/, 2009; “Weniger Wirbel an Flughäfen: DLR testet neues Verfahren zur Entschärfung von Wirbelschleppen”. Deutsches Zentrum für Luft- und Raumfahrttechnik, http://www.dlr.de/dlr/desktopdefault.aspx/tabid-10081/151_read-6937/year-all/#gallery/9611, 2013. “Intelligent Transportation Systems For Traffic Signal Control”. U.S. Department for Transportation, http://ntl.bts.gov/lib/jpodocs/brochure/14321_files/a1019-tsc_digital_n3.pdf.

• Reduce headways: A system that requires large headways (intervals or distances between units) can accommodate and process fewer vehicles, passengers or items of cargo. To reduce the headways, operators need to introduce a coordinated and sophisticated form of system management with enhanced user information and control, without compromising user safety. Some examples are provided in Figure 12, along with various innovations expected in this area.
• Reduce technical losses: Physical leakage is a major issue in water and electricity transmission and distribution systems, owing to low-quality design and construction, insufficient maintenance and ageing components. About 45 million cubic metres of water is lost daily in the developing world as a result of physical leakage – enough to meet the water needs of 200 million people.⁵⁰ And the loss of potential water revenues in some parts of Africa is often as high as 40-50%. To reduce the losses of water or electricity, the following steps are indicated:
• Use technology and analytics to detect leakages. For example, in Malaysia’s Selangor state, the installation of pressure control in the water distribution network reduced leakage by more than a quarter.⁵¹ Similarly in the UK, an advanced pressure management system with software, sensors and controllers is used to detect leakages early on, and has reduced water loss by 1.5 million litres per day.⁵² 
• Conscientiously and promptly repair leakages. In Bangkok, more than 150,000 leaks were repaired and 551 km of mains were replaced between 1997 and 2004, by using performance-based service contracts that incentivized the private contractor on actual leakage reduction, effectively reducing the non-revenue water ratio from 42% to 30%.⁵³
• Invest in new equipment. For example, replacing old, high-loss distribution transformers by modern high-efficiency transformers, as done in large programmes in India and China, can reduce losses by up to 80%. Globally, this approach could reduce energy consumption by 200 terawatt-hours per year, which is equivalent to the Benelux countries’ entire electricity consumption.⁵⁴

Increase effective throughput by reducing commercial losses.

Effective throughput is impeded not only by technical issues, but also by commercial losses. For example, “commercial leakage” in the developing world accounts for 30 million cubic metres of water that are consumed daily but not paid for.⁵⁵ The causes include operational issues such as poor metering, billing and debt collection, employee corruption, and illegal connections and theft. Commercial leakage is not confined to water and electricity utilities, but also occurs in the transport sector (although it is less pronounced there), through toll evasion on highways and fare-dodging on public transport. Several measures can be taken to reduce commercial leakage:

• Install improved or smart meters, making customer metering more reliable, and use anti-corruption measures to enforce correct readings. Phnom Penh’s Water Supply Authority, for example, increased meter coverage from 12% in 1993 to 100% in 2008, and introduced an incentive-based payment scheme for meter-reading staff, correlated to their collected bills. The result was an increase in the debt-collection ratio from 50% to 99%, and only a 6% non-revenue water ratio (down from more than 50%).⁵⁶
• Improve debt collection. In São Paulo, contractors were offered incentives to collect on outstanding bills; the initiative raised US$ 43 million, equivalent to 78% of the bad debt, within two years.⁵⁷ 
• Prevent theft and improve enforcement. Closed-circuit television and system protection devices can be used to prevent theft, and enforcement can be improved by pressing for revised laws and collaborating with the police. 
• Combat illegal connections by means of marketing campaigns and public participation. For example, in South Africa, a national campaign was conducted via the Internet, posters and media to curb illegal connections, including the option of reporting electricity thieves anonymously. This campaign led to the discovery and disconnection of about 80,000 illegal connections and tampered meters.⁵⁸ In Delhi, India, authorities have reduced theft by using a “social audit” and information campaigns on the dangers of tapping electricity from live wires.⁵⁹ 

In combination, these measures can make a particularly strong impact. The State Electricity Board in Andhra Pradesh, India launched a comprehensive drive to regularize its finances. It backed a new law that punishes electricity theft, and introduced IT-supported metering (protective boxes on transformers) as well as new tools to analyse customers’ monthly consumption and to trigger alerts. The board also embarked on an anti-corruption fight: inspectors have to issue a numbered report and receipt to customers, and users are given a one-time opportunity to obtain an authorized connection after paying a fine. The cumulative impact of those measures was a reduction of electricity losses from 38% to less than 20%, and a regularization of 2.25 million unauthorized connections.⁶⁰ In the water sector, Manila Water of the Philippines provides a good example of what can be achieved by applying similarly broad measures; it drove down its non-revenue water ratio from 63% in 1997 to just 11% in 2010.⁶¹

Apply demand management

Demand-side strategies, aimed at redistributing demand in time, space or mode, are equally important in making the most of existing capacity. They often present a cost-effective alternative to increasing capacity, and also have the potential to deliver better environmental outcomes, improved public health and more prosperous and liveable cities.

As Tony Blair declared during his time as British Prime Minister, “We cannot simply build our way out of the problems we face. It would be environmentally irresponsible – and would not work.” ⁶² Far preferable would be a comprehensive application of demand management techniques; this could, for instance, reduce peak-period car travel in British urban areas by over 20%.⁶³ The opportunities for applying demand management have increased greatly, thanks to technological progress in metering, billing and payment, such as e tolling and smart meters. 

Four broad approaches are available: time-based user charges; self-regulation through improved information; increased operations control; and a shift of demand across mode and space.

Employ static or dynamic time-based user charges.

Figure 13: Overview of Time-based User Charges

 

Introducing time-based peak pricing provides users with powerful incentives to adjust their behaviours and shift their usage patterns (Figure 13). This approach is more relevant for infrastructure assets serving individual consumers (whose usage patterns show peaks in time) rather than industrial users (who tend to be more stable throughout the day). 

– Use time-based price segmentation wherever appropriate: Such segmentation is suited to almost all sectors of infrastructure. For example, many airport tariffs are adjusted by time of the day. Many electricity contracts in Italy and Sweden include time-of-use tariffs, enabled by a broad smart meter roll-out. Singapore has led the way on congestion pricing for urban roads; in 1998, it introduced its Electronic Road Pricing system, where rates are adjusted based on a three-monthly review of actual congestion to achieve the targeted optimal speed range. The system has led to increased use of public transport, and has reduced traffic by 10-15%, particularly during the morning rush hour.⁶⁴ 

• Consider dynamic pricing: Although this technique has been little used up to now, it looks very promising. Prices are not preset in line with assumed peak times, but are dynamically adjusted in line with the actual congestion in the network. For example, State Route 167 in the US state of Washington introduced HOT lanes with dynamic prices for single-occupant vehicles, with a range of US$ 0.50 to US$ 9.00 depending on real-time traffic levels updated every five minutes. As a result, the regular lanes also benefited during peak hours: speeds have increased by over 20%, collisions are down by 2% and the number of vehicles has decreased by 5%.⁶⁵
• Maintain a clear customer focus and take social mitigation measures: Peak pricing does tend to arouse criticism and public discontent; users complain about the extra cost burden, and some policy-makers and social activists criticize the tariffs as being inequitable. However, while time-dependent pricing is often used for optimizing yield, it can be implemented as revenue-neutral (“zero-sum pricing”). In that way, it becomes more socially and politically acceptable. Operators can also take other steps to soften the blow, for example:
• Dynamic toll lanes in Puerto Rico allow access for the local Bus Rapid Transit (BRT) system (assuring transport for all social classes) as well as car drivers at certain times if they pay a toll (assuring financial sustainability of the operator). The rate varies according to actual traffic density, and the system is updated every five minutes to avert congestion and ensure the free flow of general traffic and the BRT.
• In the US, Baltimore Gas & Electricity first piloted time-of-use pricing and carefully monitored customer reactions. For the roll-out, a high level of customer service was assured by providing energy reports, investing in advanced meters and retaining optionality for users. The result was a high customer-satisfaction rate, while achieving the goal of reducing peak demand by 18-33%.⁶⁶ 

Promote self-regulation through user education and information. 

Customer behaviour is driven by more than just financial incentives. In fact, if users perceive the value of shifting their demand patterns – value such as less time lost or better environmental outcomes – they might intrinsically adapt their behaviour. In some settings, however, additional consumer education is needed on the potential of savings and appropriate measures, as in the São Paulo Slum Electrification and Loss Reduction Programme in Brazil. If customers are educated about the potential impact, all they need is the relevant information to act. Technology is making such information increasingly available. Smart meters, for example, enable customers to “see” their usage profile in real time and take appropriate action. A survey in North America found that 71% of consumers believe that detailed water usage data would encourage them to save water.⁶⁷ The various technologies employed in the transport sector can be considered, ranging from asset-heavy solutions on the infrastructure side to asset-light IT on the user side:

• Asset-heavy: Hong Kong’s Route 8 highway, for instance, has traffic displays providing real-time congestion information with warnings, and also implements passive and active diversion.⁶⁸
• Asset-light: Traffic and navigation apps such as Waze (community-based and crowd-sourced) are now available. Drivers passively contribute real-time traffic data, or actively report accidents and any other hazards; the app then provides other road users with an up-to-the-minute account of road conditions and suggests an optimized route. 

Increase operations control. 

In many cases, promoting self-regulation may not be sufficient; explicit usage limitations may be required, which can usefully complement the pricing approaches while avoiding the social-exclusion effects of user charges. Administrative slot allocation at airports is one example, and many cities, from Athens, Greece to Quito, Ecuador, impose road space rationing based on licence plate numbers. 

Shift demand across mode and space.

The various techniques just discussed – static and dynamic peak pricing, self-regulation and operations control – can facilitate demand management not just by reducing demand or by redistributing it more evenly across time, but also by spreading it across space and mode. Examples include: 

• Shifts in space: In France, to discourage diversions of truck drivers from tolled highways to free regional roads, authorities are planning a satellite-based tolling system to charge trucks even when they are on these non-toll regional roads. 
• Shifts in mode: To encourage cargo companies to use rail rather than road transport, Switzerland introduced a heavy traffic toll, based on distance, weight and emissions. As a result, heavy-truck traffic across the Alps has slightly declined over the last ten years despite increasing cross-border trade. Canada’s Central Okanagan region, formerly the most car-dependent region of British Columbia with 85% of suburban commuters driving to work in single-occupant vehicles, set about to redress the balance. It raised parking prices above the cost of a public transport pass; launched a carpooling initiative; introduced a school-based, green transport educational programme; and expanded infrastructure for bicycles and public transport. The result was a surge in bicycle commuting, with one in seven residents bicycling to work in 2004, and the region’s highest growth rate in public transport usage.⁶⁹ 

To succeed in shifting usage in mode or space, the best strategy is not only to impose punitive pricing on the traditional, unfavoured option, but also to ensure that the new, favoured option offers greater convenience and efficiency. In the Swiss case mentioned, the railway option became more competitive because the government invested in modernizing the rail infrastructure, and introduced reforms that gave rail companies greater flexibility and entrepreneurial freedom.

The work of the World Economic Forum in Tianjin, People’s Republic of China, reflects another wide-ranging concerted initiative, involving systemwide throughput optimization and demand management measures (Box 3).

Optimize availability and reduce downtime

Asset availability may be constrained by legal issues, for instance with night-time restrictions on port and airport operations. In such cases, the unused capacity can only be released through regulatory changes. For other types of downtime, however, resolution lies within the power of the infrastructure operators themselves.

Asset downtime certainly represents a challenge for operators, and reduces reliability for users. Eight out of 10 ports suffer from unscheduled downtime, and of those, almost half are down at least 10% of the time.⁷¹ These challenges are increasing as the stock of infrastructure assets ages. For example, Germany’s Kiel Canal, the most travelled artificial waterway in the world, had to close for several days in 2013 for repairs to its inadequately maintained locks. This downtime required detours of 250 nautical miles (463 km), costing about
€ 70,000 on average per vessel.⁷² 

To increase availability, operators should take the following measures when appropriate and feasible:  

• Reduce the number of scheduled downtimes by adapting the maintenance cycle and by bundling maintenance tasks into a one-time intervention. 
• Minimize the risk and number of unscheduled breakdowns by undertaking regular and reliable preventive maintenance and by adhering to strict construction standards.
• Reduce the downtime of each outage by optimizing the repair and maintenance processes. For example, Skanska used rapid-strength concrete for road paving bay replacements on the UK’s M25 motorway to minimize lane closures and increase road availability for drivers. Autostrade per l’Italia has broadly re-engineered its maintenance processes for bridges and viaducts, reducing the share of maintenance tasks with medium-to-severe traffic interference from 50% to 10%. Shift work can keep construction sites active, and thereby also speed completion of repairs: in Germany, for instance, highway works currently use only two-thirds of the maximum possible daylight working hours.⁷³
• Consider operations requirements in maintenance planning. Autostrade per l’Italia schedules short-duration maintenance tasks for off-peak hours, minimizing the inconvenience to drivers if congestion could be expected during daytime works.
• Keep the systems running during maintenance works by properly planning deviations and providing temporary alternatives. For example, Skanska, while replacing the movement joints underneath the Queen Elizabeth II Bridge on the M25 motorway, installed an innovative ramp to reduce the duration of lane closures and increase bridge availability for drivers. The Panama Canal duplicates key components to ensure 365-day, 24-hour service; two pairs of canal locks and two pairs of valves for the lock chambers exist, so replacements can be made without interrupting normal operations.
• Improve incident management. Accidents, other incidents and construction work jointly account for up to 25% of road congestion,⁷⁴ so efficient incident management is crucial, including accident prevention measures, a quick-response rescue service, rapid clearance of accident sites and localized weather forecasting to alert snow removal teams. London is improving the management of utility construction sites with a web-based utility management plan, a system piloted in Birmingham: if proposed water and electricity utility works are likely to interrupt traffic, the operator is assigned a specific time slot for carrying them out, and has to pay a penalty if the deadline passes before completion.

As all the measures come at a price, the objective is not to maximize availability but to find the optimal operating range – to balance the costs of implementing the various measures against the benefits, such as saved user time and revenues. Aircraft operators and manufacturers serve as good examples; their sophisticated quantitative models determine optimal O&M schedules for reducing downtime.