Pavement marking in daylight with poor quality cannot provide a reference for drivers to specify their own position relative to nearby vehicles. Luminance and Correlated color temperature (CCT) of sunlight is of importance for daytime visibility of in-service pavement markings, which lacks detailed consideration. This paper aims to explore the daytime visibility requirements of in-service pavement markings considering the influence of natural light characteristics. Based on analyzing the mechanism and impact factors of daytime visibility of pavement markings, a subjective scale of pavement markings state in the drivers’ field of view was proposed and a short and bold line was recommended as the standard state. Thirty-six tested drivers were randomly selected to detect white and yellow markings of both 15 cm and 20 cm width under 2000 to 23,000 lx and 5500 to 8500 K for outdoor natural light environment. The luminance contrast of the pavement marking to the surrounding road surface ranged from 0 to 10. The result indicated that the natural light with 2000 to 3000 lx and 7500 to 8500 K is the most unfavorable light environment for drivers to recognize pavement markings during daytime. The detection distance is becoming longer with the increase of luminance contrast. The detection distance does not increase with the increase of luminance contrast when the luminance contrast of white markings is greater than 4 and that of yellow markings is greater than 3. The model was established expressing the relationship between luminance contrast and Q_d contrast. The preview time 3.65 s was selected to calculate the minimum requirements of Q_d at speeds of 60, 80, 100 km/h, respectively, for different types of markings. The results can provide scientific evidence for quality evaluation and maintenance management of pavement markings in service for daytime visibility.

Chinese cities are increasingly developing exclusive bicycle paths to improve the safety and efficiency of bicycle transit. The width of bikeways is a critical factor influencing cyclists’ safety and comfort, with insufficient width identified as a major contributor to bicycle accidents. Therefore, determining the minimum operational width for human-powered bicycles is essential for bikeway design. While some countries’ design manuals consider speed as a factor in determining width, there is a lack of field experiments to validate these specifications from the perspective of cyclists’ safety and comfort. This study addresses this gap by conducting a field experiment to measure cycling workload, which reflects safety and comfort under different widths and cycling speeds. The experiment involved 12 cyclists on a test road, where cycling workload was measured at various preset widths and cycling speeds for a single human-powered cyclist. The results were further validated using conventional lateral distance measurement techniques, which are used in the existing literature to determine the cycling width. The results show that wider bikeway widths lead to a lower cycling workload, enhancing comfort and safety. However, both very high (over 20 km/h) and very low (under 5 km/h) speeds significantly increase cyclists’ workload, which in turn requires a wider path to maintain a safe and comfortable cycling experience. The study found that a minimum width of 0.90 m may be adequate for cyclists traveling at speeds between 10 and 15 km/h, while a width of 1.0 m is sufficient for speeds ranging from 5 km/h to 25 km/h, provided the bicycle width does not exceed 0.62 m. Given that cyclists typically progress from slower to faster speeds, a minimum operational width of 1.0 m is recommended for most cases. This study highlights the importance of considering cyclists’ workload in determining appropriate bikeway widths. It provides valuable insights for designing safer, more comfortable bike paths and reducing bicycle accidents, contributing to the sustainable development of urban cycling infrastructure.