What are the most critical factors to consider when selecting a bike light for low visibility conditions, and how do they impact the lights overall effectiveness in terms of lumens, beam pattern, and battery life? Specifically, what are the advantages and disadvantages of using a light with a focused beam versus a floodlight, and how do these design choices affect the riders ability to see and be seen on the road? Furthermore, what role do features such as pulse or strobe modes, adjustable brightness, and ambient light sensors play in enhancing safety and visibility in low-light environments, and are there any emerging technologies or innovations that are likely to significantly improve bike light performance in the near future?