Many bus drivers are exposed to health risks, due to repeated exposure of mechanical shocks when frequentlyriding over traffic speed bumps. This paper presents recent results from an investigation of vibrations imposed onthe driver from some twenty speed bumps in the Stockholm area (Sweden). The vibrations have been evaluatedin accordance with the new standard ISO 2631-5. It defines a method of quantifying whole-body vibrationcontaining multiple shocks (such as bumpy rides) in relation to h uman health. It uses peak vibration (shock)values to predict compression stress in the spine, and reports equivalent daily static compression dos e, Sed. Theresults show high Sed -values with high health risks even at low speeds. This finding made the Swedish WorkEnvironment Administration prohibit line bus traffic on the related streets until some speed bumps were altered.The health risk depends on the number of daily shock exposures. On the worst investigated road the speed limitis 50 kmph (30 mph), while the maximum acceptable speed was 10 km/h (6 mph) assuming 150 bumps per day.