A Tool for Assessing the Effectiveness of Speed Humps as Traffic Calming Measure

Authors

• Abdulrazak Mzamiru Kachwamba, Tanzania National Roads AuthorityFollow
• Enock W. Nshama, University of Dar es SalaamFollow

ORCID

https://orcid.org/0009-0001-3325-0933

Abstract

Urban population growth and increasing motor vehicle usage continue to raise concerns regarding road safety in rapidly developing cities. Although previous studies have assessed traffic-calming effectiveness using multiple criteria, they have analysed the criteria separately and have not developed a composite tool for classifying overall effectiveness. This study develops a quantitative assessment tool designed to compute a weighted composite score for evaluating the effectiveness of speed humps as a traffic calming measure. Stakeholder questionnaire responses, complemented by descriptive analysis and exploratory factor analysis, were used to identify key indicators of effectiveness and the variables influencing them. Findings indicate that speed reduction and accident rate reduction emerged as the primary effectiveness indicators, both receiving high relative importance scores. Five variables were identified as the most influential in determining effectiveness: hump visibility, the presence of road signs, visibility of road signs, hump dimensions, and hump spacing.

A pilot application of the tool was carried out on the Goba–Mbezi Mwisho road, where vehicle speed and accident records were examined before and after the installation of selected humps. The assessment tool generated an overall effectiveness score of 50.1%, indicating effective enough performance. Observed reductions in vehicle speeds and accident occurrences supported the operational relevance of the tool. Validation results showed a 99% consensus rate among reviewers, demonstrating strong agreement regarding the tool’s usability for assessing the effectiveness of speed humps in similar urban contexts.

Recommended Citation

Kachwamba, A. M., & Nshama, E. W. (2026). A Tool for Assessing the Effectiveness of Speed Humps as Traffic Calming Measure. Tanzania Journal of Engineering and Technology (TJET), 45(2), 167-180. https://doi.org/10.65085/2619-8789.1064

Publisher Name

University of Dar es Salaam