Final answer:
The best way to locate bumps in the road when riding at night is to feel for vibrations through the handlebars, use your bicycle's lights to see ahead, and avoid direct exposure to bright headlights.
Step-by-step explanation:
When riding in traffic at night, the best way to locate bumps in the road is to feel for vibrations through the handlebars. Using your smartphone flashlight while riding is unsafe, and looking for reflective road signs would not directly indicate where bumps are. Instead, paying attention to the tactile feedback from your bicycle's handlebars can help identify variations in the road surface. Additionally, maintaining a proper lookout ahead and using the lights on your bicycle are essential for spotting obstacles. Remember that you should never look directly at very bright lights, such as headlights on your car, as this can impair your vision and increase the risk of an accident.