Author(s): Maria Santos, Jorge Martinez, Henrik Johansson and Klaus Müller

Abstract: Traffic calming devices such as speed breakers and road humps are widely implemented on local streets to reduce vehicle speeds and enhance pedestrian safety. However, when these devices are poorly designed or remain unmarked, they may generate unintended consequences related to driving behavior, vehicle operating efficiency, and fuel consumption. This research presents a micro-level assessment of the impact of speed breakers and unmarked humps on operating speed and fuel use on selected local streets. Using short roadway segments characterized by frequent vertical traffic calming features, the research evaluates changes in approach speed, crossing speed, and post-crossing acceleration patterns. Operating speed data were collected through spot speed observations, while fuel consumption effects were estimated using speed-acceleration profiles and established fuel-use relationships. The analysis highlights that unmarked humps produce abrupt speed reductions, leading to higher acceleration demands immediately after crossing, which in turn increases instantaneous fuel consumption. In contrast, properly designed and visibly marked speed breakers encourage more gradual deceleration and smoother acceleration, resulting in relatively lower fuel penalties. The findings indicate that repeated cycles of deceleration and acceleration on streets with closely spaced humps substantially reduce average operating speeds and elevate overall fuel use per unit distance. Such effects are more pronounced for two-wheelers and small passenger cars, which dominate traffic composition on local streets in many developing regions. Beyond fuel impacts, inconsistent speed control also contributes to driver discomfort and increased risk of vehicle damage. The research underscores the need to balance safety objectives with operational efficiency by adopting standardized geometric designs, adequate advance warning signs, and reflective markings for speed breakers. By quantifying the micro-level operational and fuel impacts, the research contributes evidence to support more context-sensitive traffic calming policies. The results suggest that well-marked and uniformly designed speed control devices can achieve speed moderation goals while minimizing unnecessary fuel consumption and associated environmental impacts on local street networks.

DOI: 10.22271/27078329.2026.v5.i1a.63

Pages: 14-18 | Views: 62 | Downloads: 27

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