Evaluation of Dragon Teeth Markings in High-Speed to Low-Speed Transition Zones on Rural Highways: An Empirical Study in a Developing City

Abstract

City gateways pose significant road safety challenges because of the required reduction in driving speeds from high-speed rural highways to low-speed urban environments. Traffic calming markings, such as transverse bars, have traditionally been employed to address these safety concerns. However, their effectiveness is limited in Mexico owing to their generalized and multipurpose applications. This study represents the first empirical evaluation of an alternative traffic calming measure, known as dragon teeth markings, within a developing context. Three high-speed to low-speed transition zones at city gateways in Uruapan, Mexico, were selected to compare vehicle speeds under three distinct scenarios: dragon teeth markings, traditional transverse bars, and no markings. Vehicle speed data were collected over eighteen weeks using traffic radars, and statistical analyses, including paired t-tests and nested random forest models, were conducted to quantify speed reductions and identify influential factors. Additionally, a driver survey (n = 342) evaluated driver awareness, behavioral responses, and perceived safety related to the markings. Results showed that dragon teeth markings achieved statistically significant speed reductions of up to 12 km/h compared with traditional transverse bars and unmarked scenarios. Influential factors, such as traffic flow rate, density, and speed limit violations, significantly affected the magnitude of speed reductions. The survey results indicated that the majority of drivers noticed the markings, exhibited speed reduction responses, and perceived a safety improvement. These findings provide valuable insights for traffic agencies concerning the efficacy of dragon teeth as a promising traffic calming marking in developing regions.