Bologna introduces the 30 km/h obligation, but is it true that this limit reduces accidents?

Tuesday January 16th 2024, the ordinances requiring the speed limit at 30 km/h in much of the Municipality of Bologna. Following the checks carried out by Local policesome people have already been fined – the first was a man going at 39 km/h – and the measure has already triggered controversies and reactions of all kinds (both positive and negative).

It is not difficult to understand the reason: on the one hand the decision of the Municipality of Bologna, the first in Italy to become a 30 km/h city, wants improve safety on the roadsreducing the risk of serious accidents especially for pedestrians, cyclists and motorcyclists; on the other hand, if you usually use the car to get around, you know that you can maintain such a slow pace it’s complicated, both from the point of view of sensitivity on the accelerator pedal and, consequently, the need to continuously look at the odometer, taking your eyes off the road. Going at 30 km/h can be unnerving: driving can paradoxically become more difficult and, especially if you are in a hurry, the sensation is almost that of not moving, of not proceeding.

limit 30 km h bologna speed cameras

This is why it is important that the measure actually has some concrete positive effects on reducing the number of accidents with victims. Sure, a driver might be angry about the introduction of the limit, but if it actually saves lives, I think we can agree that it’s worth accepting the change and changing your habits. So here we have recovered the data of one of the most important research in the sector: it is the report LUSTRE, Lower urban speed limits in Europepublished in May 2023 and created by experts from some universities in Northern Europe andEuropean Transport Safety Council.

Data on the reduction of accidents in cities with a 30 km/h limit

The LUSTRE report collects data from United Kingdom and from six other European countries where the speed limit of 30 km/h (or 20 miles per hour) has already been introduced in several cities since the 1990s. Let’s talk about Sweden, Norway, France, Germany, Swiss And Netherlands.

slowing speed bumps

In summary, the main evidence of the study are the following:

  • In the United Kingdom, accidents resulting in fatalities have decreased overall by 23%. If we go into detail, we are talking about a reduced percentage, the11%if the imposition of the limit was not accompanied by the installation of physical structures or devices that led to a mandatory reduction in speed (such as speed bumps, for example, or speed detectors) and by a much higher percentage, of the 40%where instead there was their introduction.
  • Disaggregated data is not available in the six European countries: in general, however, it has been seen that the number of accidents causing victims has decreased by 18% thanks to the introduction of the 30 km/h limit.
  • The fact that the introduction of physical structures or devices, such as slowing speed bumps oh speed detectors, positively affects a greater reduction in accidents with fatalities depends on the fact that they produce a sharper reduction in the speed of motor vehicles. In fact, it has been seen that, in their absence, motorists tend to maintain more or less the same average speed that they maintained before the imposition of the 30 km/h limit and reduce it slightly.
  • Finally, the number of accidents with victims is lower in the presence of further interventions to modify road traffic, such as the construction of cycle paths ol’widening of sidewalks.
bicycle lane

Does the 30 km/h limit reduce accidents with fatalities?

In conclusion, we can say that the data are comforting but, in order for the speed limit at 30 km/h has a real impact on reducing accidents with victims, it must be combined with other interventions: the introduction, for example, of speed bumps, speed detectors or other structures and devices that lead to a concrete reduction in the speed of motor vehicles; and the modification to road traffic with the creation of preferential lanes for the various means of transport (such as cycle paths).