A new software update coming to the Tesla Autopilot feature will allow the cars to recognize speed limit signs with its cameras and act accordingly. With this new feature, your Tesla car should stick to the limit. Simultaneously, the update also brings a new feature where a chime can be heard when the traffic light turns green while you're at an intersection. If there's a car ahead of you, the chime will wait for that vehicle to move before it chimes. The update is rolling out now, but you might have to wait a bit before it reaches your electric car.
Source: Engadget