NOx and the city
Traffic management

NOx and the city

Thursday, 21 June 2018

As city authorities are increasingly pressing for tighter controls on air pollution, James Allen looks at how low emission zones are evolving to meet the higher expectations

In many cities, the low emission zone (LEZ) is now an established weapon in a road authority’s armory in its quest to combat urban air quality and congestion. However, for some, the LEZ is still very much an unknown quantity to be approached with caution. Europe has been at the forefront of LEZ trials and testing, with many schemes now developing and evolving, so it is a little peculiar that Brussels, the Belgian – and de facto European Union – capital is jumping on the LEZ bandwagon at this relatively late stage.

Holding back, however, has enabled its road authorities to consider what has worked elsewhere and introduce an LEZ on a scale that few others have so far achieved. The vast majority of schemes have focused on relatively small areas, confined to the few streets designated as the city center, but Brussels’ LEZ covers the city’s entire 161km2 (62 square miles) land space that falls within the R0 ring road.

By contrast, the LEZ in Antwerp – the first in Belgium, introduced in February 2017 – is restricted to 20km2 (7.7 square miles) of the city center. “There are differences between the two systems, but it was much easier for us to plan the Brussels LEZ because of the Antwerp project,” explains Sarah Hollander, head of sustainable mobility for the city of Brussels.

“We allowed it to inspire us. The reasons for it being so different are political but also practical. The Brussels zone is much bigger because it was logical to cover the whole territory inside the ring road.” The sliding-scale scheme allows initially all but Euro 1 diesels into the region, but gets increasingly stricter until 2025, when only Euro 6 diesel vehicles, and Euro 3 petrol vehicles, will have unfettered access to the city.

It means that, for this first year, only about 1% of vehicles entering Brussels will be affected, but this was no accident, according to Hollander. “We didn’t want to start with too many cars, otherwise the acceptance by drivers would have been much more difficult and it gives us timeto prepare the public to change their behavior and accept the measures,” she explains. Prohibited vehicles will be afforded a maximum of eight days’ access to the city annually upon purchase of a pass amounting to €35 (US$43) per day.

Offending vehicles are currently not being fined as the system beds in and the citizens get used to their entire city being one big LEZ. The scheme will rely on ALPR technology, with 176 Macq-produced cameras deployed around all the boundaries, as well as inside the zone. Hollander says, “The cameras used for enforcing the LEZ are also used by the police for protection and security purposes; some were therefore positioned according to police needs, while others were installed in order to ensure full coverage of the LEZ.”

It is a little premature for organizers of the scheme to be able to say with any certainty what impact the measures have already had on traffic and air pollution; however, there are growing doubts that LEZs, in their current guise, can actually achieve what they’re intending to.

Rearranging the deck chairs

“The key challenge for LEZs is that even newer diesel vehicles aren’t that much cleaner and are, in some respects, arguably worse,” worries Dr James Tate, associate professor for the Institute for Transport Studies at the University of Leeds. In addition to his role in academia, Tate is an established road transport emissions advisor, shaping policy on improving air quality for various UK government departments and governmental bodies.

The Dieselgate scandal that Volkswagen Group was so publicly embroiled in brought attention to the lack of robustness around engine standards, and Tate believes that designers of LEZs are continuing to misunderstand the issue. “To be effective, you need to restrict access to all but those diesels that comply with on-road testing measures outlined in Euro 6 standards, otherwise you’re not reducing emissions but just encouraging vehicle stock turnover.

“Euro 6 cars actually have to comply with on-road testing so will be a lot cleaner because, up to and including Euro 5, is only really addressing particulate matter and hardly addressing the NOX issue,” says Tate. It is perhaps an acknowledgement of such criticisms that conversations around air quality are moving on from LEZs, with more and more city authorities making public their commitment to ultimately ban all diesels and, in some cases, all petrol-powered vehicles too.

No emission zones

The UK’s Oxfordshire County Council, in cooperation with Oxford City Council, have outlined plans that, if enacted, will make Oxford the first city in the world to have a no emission zone (NEZ). The county council’s principal transport planner, Martin Kraftl, explains, “It was quite clear, even back in 2014 – when the concept of the NEZ was first privately discussed – that battery technology was maturing. “Therefore, we wanted to see how ambitious we could be and, because we wanted to give certainty to businesses investing huge amounts in their fleets – such as bus companies – we didn’t want to keep on changing the requirements every few years.”

By 2020, the plan will see a small area of the city center (approximately 300 x 300m) free of all vehicles powered by traditional fuel types, this will then expand by 2030 to cover Oxford’s current LEZ, in place since 2014. The LEZ only targets public transportation, requiring all buses to meet Euro 5. “Buses are by no means the only contributor to poor air quality, but they have been the single largest source of pollution in our city center for a long time, and that’s partly because in 1999 we already began restricting other traffic in the city center. “We used to have problems with particulate matter in the city. We don’t anymore – now NOX is our main concern. It has come down by about 30% in the LEZ but, as has been widely discussed, Euro 5 didn’t perform as well in the real world as was hoped, so reductions weren’t actually as significant as had been promised.”

Universal support

Still to be officially rubber-stamped, the NEZ is on track for 2020, with strong backing of the proposals from across the disparate stakeholders living and working in Oxford. It is no accident that this wide support has been achieved, according to Kraftl: “We’ve been keen to emphasize that we’re not saying, ‘Here’s a zone – go and sort yourselves out’.” He says, “This is something we’d like to achieve for the city and it is as much our responsibility as it is theirs, so we’re working with people to break down the barriers. But the position is very much that we’re aiming to introduce exactly what we’ve consulted on.”

Because the LEZ targeted only buses, compliance was universal and no enforcement was necessary. It is a different story, however, regarding the NEZ. “It is going to be much more complicated because we are rolling this out to all vehicles and that will require camera enforcement. We already have cameras for existing traffic restrictions in the city center that we colloquially refer to as bus gates, so there is some potential to use existing systems, but we will need a lot more equipment and that’s one of the things we’re working through now.” The expectation is that, particularly for the first phase, given the limited numbers of points of entry, enforcement will be relatively straightforward with ALPR camera deployment.

An alternative approach

Paris is exploring an alternative way of dealing with polluting vehicles on its roads. The French capital’s air quality has received a lot of press attention for all the wrong reasons, with excessive levels of smog visibly smothering Parisian streets for days on end. The city’s mayor, Anne Hidalgo, has announced she wants to rid the city of all diesels from 2020, but, in the meantime, responsibility for limiting harmful emissions has been partly outsourced to parking management company ParkNow.

Since January 1, 2018, on-street parking tariffs have been amended depending on the air quality in the city at the time. When excessive levels of NOX, sulfur dioxide and/or particulate matter are detected, residents already parked in the city are automatically given 24 hours’ free parking. At the same time, to discourage drivers from entering the city, parking rates are raised.

“For the moment, it doesn’t affect tourists,” says Olivier Koch, ParkNow sales manager. “In France, it is hard to change tariffs for all vehicles, so we are focusing on residents, but there are 50,000 resident parking permits in Paris, so that’s not insignificant.” A government-run, publicly accessible website monitors the air quality of the city, updating the situation on an hourly basis. Excessive readings are then relayed to the public through media channels to inform the public, while ParkNow app users also receive notifications on their smartphones.

A few months in and the early signs are positive. “We are seeing a decrease in traffic on pollution peak days of around 30%, so there are already some quick wins, but it is very early to say for sure that ‘Yes, this is the solution to all our problems.’ We don’t expect it to be the magic pill though, but rather to form part of a wider answer to the problem of vehicle emissions and road congestion,” says Koch.

It’s clear that LEZs play a key role in addressing air quality issues but, as awareness grows, the measures introduced are also adapting to the greater expectations.

Source: James Allen, Traffic Technology International

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