Tempo 30 zones: quiet but useless

Since July this year, one of the main traffic axes of the city of Mainz has been completely a 30 speed limit zone. This has been achieved with further measures, among other things, to avert diesel driving bans at literally the last second. Now, after almost half a year, a summary can be drawn. During a survey, the residents unanimously put on record that it has become noticeably quieter. This change is also confirmed by a measurement of the daily continuous sound level on the aforementioned road sections. Thus, a decrease of 3.0 decibels (A) compared to the previous year's value was recorded, as the responsible transport department head Katrin Eder (The Greens) stated to the Frankfurter Allgemeine Zeitung (F.A.Z.) on Wednesday. Eder also described Mainz as proof that inner-city speed limits would lead to a "considerable reduction in noise". 
But what about the air quality, why this zone was introduced in Mainz in the first place? According to Eder, it is still too early to discern a trend here. However, the German Environmental Aid Organisation (DUH) is not moving fast enough. According to F.A.Z. information, the DUH is already aiming for a new lawsuit before the Higher Administrative Court this week, as the state capital continues to exceed the European-wide limit of 40 micrograms per cubic meter.
Mainz's past efforts with an air pollution control plan do not seem to be sufficient to implement the DUH's demands, although many measures have been tackled on the Rhine, such as the retrofitting of the city's bus fleet or the expansion of cycle paths in addition to an almost complete city centre with Zone 30. 
When will those responsible in Mainz come to terms with the apparently inevitable fate for their city in the form of a ban on diesel driving? 
 

As always, we will keep you up to date on the developments surrounding a new court case in our daily blog.