Barely a week goes by without the latest plan or initiative aimed at reducing emissions or reducing levels of air pollution. This coming week will see the latest in this long line, when Beech Street in the City of London becomes one of the first zero emission streets in the country.

We can see the logic in the plan. Running for 18 months, only zero emission vehicles will be allowed on the street. The current bus service that runs down it is already zero emissions. Cycling and walking are unaffected of course.

But something doesn’t quite sit well with us on the principle of banning, when targeting efforts on the most polluting vehicles may be a better option. There is the matter of what vehicles are exempt. Emergency vehicles are exempt, of course, as are refuse and delivery vehicles.

While the majority of traffic will be redirected away from the street, the decision to allow vital heavy-duty vehicles means the zero emission street’s effect on pollution levels is far from certain.

It is likely that most private vehicles may simply re-route, especially onto London Wall and Old Street. We have not seen detailed modelling that would indicate what the impacts would be, but any increase in air pollution on these streets is not an outcome anyone would wish for. And these are locations with NO2 and PM10 levels on both streets already touching legal limits.

But most importantly is the fact that regulation and restriction should always be a measure of last resort. Through fusing air quality data and vehicle presence data, targeted actions against the worst offenders for air pollution can have a significant impact on reducing air pollution. This would allow the City to understand the impact all vehicles are having, including those that under the current scheme will be allowed onto the street without condition.

This is important, because it reflects the current technological situation. Not all trips can be transferred to bicycle, walking or public transport. Not all deliveries can be made on low emission vehicles, and whilst significant inroads have been made in electrifying fleet vehicles, widespread adoption is still some way away.

Local authorities are in a difficult situation. They have to do something to improve air quality on local streets. But they also must strike a balance between doing so, and significant unintended consequences. Beech Street offers an interesting test bed to study the impact of a zero emission street on pollution levels across the area and an opportunity to study driver behaviour.