Final answer:
If a bicyclist has their left arm extended out to the left, it generally means they are signaling to make a left turn or that they are going to move left.
Step-by-step explanation:
If you see a bicyclist on the road ahead with their left arm extended straight out to the left, you should assume the bicyclist is signaling an intention to make a left turn or move to the left.
When a bicyclist extends their left arm straight out, this is a hand signal that communicates their intent to motorists and other road users in a clear and standardized way. It is important for safety on the road that all users are aware of these signals and understand what they represent. There are other hand signals a bicyclist might use, such as extending the right arm out for a right turn or putting their left hand up with the elbow bent to signal stopping or decreasing speed. Recognizing and respecting these signals ensures better safety for both cyclists and motorists alike.