in many intersections around Austin, traffic lights won't change unless a vehicle is detected. Unfortunately, bicycles and scooters are not massive enough to trigger signal changes. I personally experience this every day on my commute: I have to get off my scooter and walk over to the traffic light pole to push the pedestrian's button in order to get the light to change. This is an improper and potentially dangerous action for me to take, but it beats a) waiting for a car to come so the detection happens or b) running a red light.
I know that technology to detect scooters and bicycles exists. Disclaimer: I actually work in the intelligent traffic system industry. I won't disclose my employer so as not to influence any particular purchase.