6 minute read
3.9 Place-Based Policies and Their Effects on Air Pollution
only safe pavements but also enhanced traffic management (for example, traffic lights at crosswalks). Additionally, place-based policies such as pedestrian zones (further discussed in the next subsection) are useful for ensuring pedestrians’ safety and relieving congested city centers of excessive traffic.
Implementing Place-Based Policies
The air in urban areas, particularly in city centers, is often significantly more polluted than the air in surrounding suburbs or rural areas. High traffic loads due to commuters, in combination with impaired air exchange stemming from multistory buildings, are among the main factors driving the generally worse air quality in urban areas. Cities around the world have thus adopted various types of policies that restrict traffic either within an entire city or in parts of it. Such place-based policies can be effective in lowering air pollution and come in different forms (see box 3.9 for some international examples). LEZs, pollution and congestion charges, and driving restrictions are the best known of these place-based policies.
BOX 3.9
Since the first low emission zones (LEZs) were implemented in several cities in Sweden in the 1990s, they have become widespread around the world, especially in Europe. Several variations on these systems are described below.
London’s LEZ and Ultra LEZ Currently, the largest LEZ in operation is in the United Kingdom; it covers almost all of Greater London and applies to a wide range of commercial vehicles that do not meet certain Euro emissions standards as well as to vans, pickups, and other morepolluting vehicles. Eligibility to enter the LEZ is monitored through an automatic license plate scanning system.
The introduction of London’s LEZ has substantially increased the rate of fleet turnover to vehicles meeting higher emissions standards. Furthermore, a significant, albeit not large, reduction of particulate matter (PM) concentration has been recorded within the LEZ (Ellison, Greaves, and Hensher 2013). Since April 2019, parts of central London are now declared to be an “Ultra Low Emission Zone (ULEZ)” with stricter regulations. In October 2021, the ULEZ was expanded to cover a larger area, including the North and South Circular roads (Lydall 2021).
Tehran’s Inspection-Based LEZ Tehran introduced an LEZ intended to replace the driving restrictions based on
(continued)
BOX 3.9
license plate numbers, even though the two systems were in place simultaneously for a time. Tehran’s LEZ bans the entrance of cars that have not successfully undergone the mandatory yearly inspection. However, the extension of the system to also restrict entry for cars not fulfilling certain emissions standards would be necessary to make it a “real” LEZ (Heger and Sarraf 2018). The cars that undergo inspections receive a sticker whose color indicates whether the emissions are low enough to enter the LEZ or are too high for the LEZ. The Tehran Air Quality Control Company, which assessed the implementation of the LEZ scheme, reports that the LEZ has been effective in reducing traffic emissions and consequently curbed air pollution.
Stockholm’s Congestion Pricing Stockholm introduced a congestion pricing system in August 2007 after a six-month trial period. The program was opposed by most of the municipalities in the country except those inside the affected zone. The charges vary depending on the time of the day and are collected automatically using license plate scanning technology. In 2016, the congestion tax was raised, with a focus on commuting hours, and outreach was extended. The additional revenues were earmarked for the extension of the Stockholm metro system (STA and Trafikverket 2015).
The system has had positive effects on air pollution levels and on the health of local children. The levels of NO2 and PM10 fell by 15–20 percent and by 10–15 percent, respectively, and the number of acute asthma care visits of children under the age of five decreased by 50 percent (Simeonova et al. 2019). Vehicles using alternative fuels were temporarily exempted from the charges through 2008, which increased sales of such cars significantly and showcased the potential to use such systems as incentives themselves (Börjesson et al. 2012). Studies on the impact on retail revenues concluded that there were no negative effects (Daunfeldt, Rudholm, and Rämme 2009).
Beijing’s Driving Restrictions Driving restrictions for vehicles, often randomly assigned based on certain parts of their license plate number, have been implemented in numerous cities around the world. In July 2008, Beijing implemented an odd-even system that restricted cars to driving only every other day based on the last number of their license plate. This system was replaced by driving restrictions that prohibited the use of cars for one day per week, again based on license plate number. During periods of particularly severe air pollution, Beijing reverts to the odd-even system. These restrictions do not apply to electric cars.
The effects of Beijing’s driving restrictions on air pollution were also positive, significantly reducing PM, with the odd-even system decreasing PM10 concentration levels by 18 percent and the one-day-per-week system by 21 percent (Viard and Fu 2015).
LEZs, which are widespread in Europe, restrict the most-polluting vehicles, usually allowing only vehicles with some sort of validation or certification into the zone (or charging them if they do not). For example, in Tehran, only cars that have undergone the mandatory annual inspection are allowed to enter the LEZ, with fines being imposed on noncompliers. In a similar spirit, congestion charges restrict access to certain areas of a city by charging a certain amount for vehicles to enter. Hence, vehicle owners’ willingness to pay serves as a criterion for entrance into the regulated zone.
One common criticism of both types of restrictions is that they affect people differently based on their income and could affect the job prospects of those who cannot afford cleaner vehicles or the charges levied. Hence, another way to restrict driving in certain areas—practiced internationally but also in the Middle East and North Africa—is to use random assignment based on license plate numbers. One typical way of doing this is to use an odd-even scheme: every other day, only vehicles whose license plates end with an odd number may enter the restricted zones; on the alternate days, only vehicles whose plates end with even numbers may enter.
Place-based measures necessitate complementary investments, and the costs to residents must be considered in their introduction. Such investments include the development of efficient public transportation systems as alternative entrances and exits for the vehicle-restricted locations. Furthermore, an effective detection and collection system must be established to detect noncompliers. Automated license plate scanning systems are often needed to implement LEZs or congestion charges, although driving restrictions based on, for example, detecting the last number of the license plate may be simpler and can be carried out manually. Typically, penalties for noncompliance are used as economic incentives. Cities should also consider ways to ease the transition for local businesses and residents in the form of allowances for switching their cars to alternatives with lower or zero emissions or offering free public transportation if they get rid of their cars.
Reducing Vehicle Emissions: The Policy Spectrum
A broad spectrum of actions can be taken to combat air pollution from vehicles in the Middle East and North Africa. The discussion above outlined some possible routes to reducing vehicle emissions. Table 3.2 provides a comprehensive overview of such measures. For each measure, a rapid assessment of the main aspects important for policy evaluation has been carried out, which is based on international experiences and regionspecific expert judgment. While not exhaustive in this regard, the selected
