Which Italian municipality is the most dangerous for road safety? Not necessarily the one recording the highest number of accidents. When crashes are normalised against registered vehicles, the geography of road risk changes - and so do the priorities for intervention. This article explains which indicator to use, what municipal-level data for the 2022–2023 biennium show, and why some of the most visible concentrations on the map require careful interpretation before becoming criteria for action.

How to assess road accidents
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Counting road accidents in absolute terms is misleading. Larger cities, with more traffic and more vehicles, will inevitably report higher figures — but this does not necessarily make them the most dangerous. To measure actual risk, the unit of measurement must change: not crashes in absolute terms, but crashes per registered vehicle. This is the indicator at the centre of the analysis carried out on Italian municipalities for the 2022–2023 biennium: average annual accidents per 1,000 registered vehicles in each municipality.
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A fragmented geography
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The resulting map is far from uniform. Road risk is not evenly distributed across the peninsula, nor within regional boundaries: geographically adjacent municipalities can record very different accident rates. The highest concentrations are found along certain stretches of central and northern Italy, while large parts of the territory record more contained values. This fragmented picture suggests that local variables — infrastructure quality, tourist flows, urban density, and mobility patterns — play a decisive role in defining the road risk profile of each area. The crash rate per registered vehicle draws a clear geography: in the municipal map below, light blue identifies the lowest values, while darker shades indicate municipalities with higher accident rates relative to their vehicle fleet.

The common thread: two-wheelers

Behind the accident risk map, a recurring element emerges: the share of motorcycles in the total vehicle fleet. The regional comparison shows that the greater the prevalence of two-wheelers, the higher the accident rate per vehicle. The trend is unambiguous: in the chart, the bubbles representing each region rise as the motorcycle share increases.

The bubbles in the chart follow a clear direction. The further right one moves — towards regions where two-wheelers account for a larger share of the vehicle fleet — the higher the data points: where more motorcycles and scooters circulate, accidents per vehicle are more frequent. The relationship is clearly visible. However, caution is warranted: the share of motorcycles in the registered vehicle fleet is certainly a key statistical indicator to keep in mind, but it does not imply a direct causal relationship. Accident rates are the product of multiple intertwined factors: urban density, road conditions, traffic seasonality, climate, and driving behaviour.

Three illustrative cases: Liguria, Tuscany, and Valle d'Aosta
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Three regions illustrate the dynamics at play with particular clarity:

• Liguria: the extreme case, with nearly 50% of vehicles being two-wheelers — the highest share in Italy — and an accident rate of approximately 4.5 accidents per 1,000 vehicles, the highest in the country;
• Tuscany: positioned just below Liguria, with a motorcycle share well above the national average and a high accident rate; this confirms that the correlation between accidents and motorcycles is not an isolated case but characterises a broad group of regions;
• Valle d'Aosta: at the opposite end, with few motorcycles in circulation and one of the lowest accident rates in Italy.

Reading the map critically

The data tells an important story but require interpretive caution. Some accident concentrations are also connected to infrastructural, economic, and tourism-related dynamics that the simple accidents-to-vehicles ratio cannot isolate.

One key factor is the presence of major high-speed national roads. According to ISTAT 2023 data, extra-urban roads account for 48.4% of total fatalities while representing only 21.4% of all accidents, with a mortality rate of 4.1 deaths per 100 accidents — nearly four times that of urban roads. This differential is not evenly distributed: it accumulates along major arterial roads running through small and medium-sized municipalities.

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H 2 A signal for road safety policy
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The map and the chart tell the same story from two different angles: the former shows where risk is geographically concentrated; the latter points to a characteristic that accompanies it — the prevalence of two-wheelers. The correlation between the diffusion of two-wheelers and the accident rate per vehicle is real and visible in the municipal data. The takeaway is one to handle with care: what matters is not only how many vehicles circulate, but which types. Regions where motorcycles are more widespread consistently record higher accident rates — a relevant signal for those planning road safety interventions.

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