University of Applied Sciences and Technology of Tehran Municipality Urban Development Policy Making 3092-653X 3 2 2026 07 02 Comparative Evaluation of Traffic Calming Measures Effectiveness in Reducing Vehicle Speeds (A Field Study in Tehran) Comparative Evaluation of Traffic Calming Measures Effectiveness in Reducing Vehicle Speeds (A Field Study in Tehran) 283 298 244599 10.22034/judpm.2026.577927.1094 FA Hassan Khaksar Assistant Professor of Civil Engineering, North Tehran Branch, Islamic Azad University, Tehran, Iran 0000-0003-0291-9128 Payam Moeini Master of Science in Road Engineering, Tarbiat Modares University, Tehran, Iran Journal Article 2025 10 23 <span>Traffic calming measures are widely used in urban streets to reduce vehicle speeds and improve road safety. This study evaluates the effectiveness of several traffic calming measures implemented in Tehran, including plastic speed humps, sinusoidal speed humps, median islands, pavement treatments, and rumble strips. Vehicle speeds were collected under free-flow traffic conditions using laser speed measurement devices. A before–after analysis framework was adopted, and independent sample t-tests were used to compare vehicle speeds before and at the location of each traffic calming measure. The results indicate that plastic speed humps, plastic speed humps combined with median islands, and sinusoidal speed humps produced the greatest reductions in vehicle speed. In contrast, rumble strips did not show statistically significant effects on speed reduction. The findings also demonstrate that speed reduction generally begins before the installation point and gradually recovers after passing the calming device. Overall, the study confirms that properly designed traffic calming measures can effectively reduce operating speeds and improve urban traffic safety. Combined calming strategies were found to be more effective than isolated measures. The results can support evidence-based decision-making for selecting suitable traffic calming measures in urban streets.</span> <span>Traffic calming measures are widely used in urban streets to reduce vehicle speeds and improve road safety. This study evaluates the effectiveness of several traffic calming measures implemented in Tehran, including plastic speed humps, sinusoidal speed humps, median islands, pavement treatments, and rumble strips. Vehicle speeds were collected under free-flow traffic conditions using laser speed measurement devices. A before–after analysis framework was adopted, and independent sample t-tests were used to compare vehicle speeds before and at the location of each traffic calming measure. The results indicate that plastic speed humps, plastic speed humps combined with median islands, and sinusoidal speed humps produced the greatest reductions in vehicle speed. In contrast, rumble strips did not show statistically significant effects on speed reduction. The findings also demonstrate that speed reduction generally begins before the installation point and gradually recovers after passing the calming device. Overall, the study confirms that properly designed traffic calming measures can effectively reduce operating speeds and improve urban traffic safety. Combined calming strategies were found to be more effective than isolated measures. The results can support evidence-based decision-making for selecting suitable traffic calming measures in urban streets.</span> https://www.judpm.ir/article_244599_df8a7fe04052a04f5a6f3252d3afb8cf.pdf