The Impact of Road Traffic Noise on Apartment Prices in Kraków: A Hedonic Analysis of the Primary and Secondary Markets

This study examines the effect of road traffic noise on apartment prices in Kraków, treated on an equal footing with the other price-forming attributes. The analysis draws on 6244 transactions from the primary and secondary markets concluded between January 2021 and June 2022. Multiple regression in linear and semi-logarithmic form was applied, and outliers were removed iteratively on the basis of standardised residuals; the sensitivity of the estimates to the adopted elimination threshold was examined and the results were compared with robust regression. The effect of road noise differs between market segments. In the primary market, in the sample after outlier elimination, the noise attribute is statistically significant and the NSDI equals 0.17% of the price per 1 dB (95% CI: 0.13–0.21%). In the secondary market, the estimate is close to zero, and the difference between the segments is significant (z = 6.0; p < 0.001). In the full samples, where prices are strongly differentiated by dwelling standard not recorded in the register, the noise effect does not reach significance, which points to the conditional character of the estimates. The influence of noise also depends on the position relative to the city centre: it is strongest in the intermediate zone (0.23%/dB), weaker on the periphery, and disappears in the central zone, where the elevated sound level is offset by the advantages of the location. The diagnostics covered VIF coefficients, sensitivity analysis, and Moran’s I for the residuals. The results, set against international research on noise capitalisation, support the routine inclusion of the acoustic climate in the valuation of new dwellings and provide a monetary reference point for noise abatement policy.