Over the last few decades, global urban planning has experienced a radical paradigm shift toward promoting sustainable mobility, prioritizing active transport through the massive implementation of cycling infrastructure and traffic-calming measures. This approach, frequently materialized through interventions known as "road diets"—which reallocate roadway space by subtracting lanes from private vehicles in favor of bike lanes and pedestrian expansions—is based on the theoretical premise of reducing greenhouse gas emissions, mitigating structural congestion, and promoting public health.

However, the physical and regulatory reconfiguration of urban space is not an economically neutral process, nor does it conform to an optimal Pareto efficiency model. On the contrary, it generates profound asymmetric externalities that reconfigure commercial dynamics, logistical efficiency, social equity, and the operational safety of cities.

Despite a considerable fraction of contemporary academic literature and political discourse highlighting the macroeconomic benefits of cycling mobility, there is a robust and growing body of empirical evidence, longitudinal data analysis, and simulation models revealing a diametrically opposed reality in numerous contexts. The central hypothesis of this thesis maintains that the deregulated or dogmatic increase of bike lanes and cyclists in an urban environment not only fails to achieve its general welfare objectives but structurally impoverishes and harms the city.

**Structural Economic Impact on Local Commerce and Retail Dynamics**

One of the points of greatest controversy and economic friction in the implementation of bike lanes is their direct impact on the financial vitality of local commerce. Institutional narratives frequently suggest that replacing on-street parking with bike lanes generates a neutral or positive impact because cyclists, despite having a lower carrying capacity per visit, supposedly make more frequent trips to shops.

However, detailed data and disaggregated analyses demonstrate that this supposed benefit is highly segmented and conditional, generating an economic "cannibalization" effect where certain business models thrive at the absolute ruin of others, impoverishing the city's commercial diversity.

**Heterogeneity of Economic Impact by Business Typology**

The impact of urban bike lanes on the commercial fabric is profoundly heterogeneous. Analytical studies utilizing "difference-in-differences" methodologies have shown that space reallocation disproportionately and negatively affects businesses selling large-volume items or those providing services intrinsically dependent on automobiles.

Exhaustive research in cities like San Francisco analyzed retail sales trends before and after the installation of bike lanes. A detailed analysis of key commercial corridors demonstrated a severe economic dichotomy. While businesses oriented toward leisure, dining, or immediate consumer goods (like coffee shops) could maintain or slightly increase sales, businesses dedicated to selling bulky goods (furniture, large appliances) experienced a significant decline in revenue after curb parking was eliminated.

A study conducted in Portland corroborated this asymmetry, showing that automobile users spent significantly more per trip ($57.39) compared to pedestrians ($31.42), cyclists ($36.61), or transit users ($35.86).

| Affected Business Typology | Observed Economic Impact |
|---|---|
| Bulky Goods (Furniture, Appliances) | Highly Negative (Sales decline) |
| Automotive Services & Hardware | Critical / Potential Closure |
| High-Volume Retail (Supermarkets) | Negative |
| Dining, Leisure, and Cafes | Neutral to Positive |

**Emblematic Case Studies and Public Policy Reversals**

Extreme economic pressure and consequent revenue loss have forced various public administrations to dismantle previously installed bike lanes. An internationally paradigmatic case is Friedrichstraße in Berlin. In August 2020, authorities closed a 500-meter stretch to car traffic to prioritize pedestrians and cyclists.

Far from flourishing, the experiment was detrimental to local commerce. Merchants initiated legal action citing severe damage to their businesses and an abrupt drop in revenue. The courts ruled in favor of the merchants, forcing the street to reopen to vehicular traffic. Similarly, the Royal Borough of Kensington and Chelsea in London dismantled a segregated bike lane on Kensington High Street just seven weeks after its installation due to formal complaints from business associations.