How to Turn Off the Speed Limit Indicator in Maps for iPhone in iOS 11
One of the more interesting features that Maps acquired in iOS 11 was the ability to show you the current speed limit for the road your driving on. But if you've been driving since before the iPhone was even invented, you're probably already pretty good at knowing what the speed limit is, which just leads to unnecessary clutter on the Maps screen.
Turns out, it's very easy to disable this new Maps feature. Just go to Settings -> Maps -> Driving & Navigation, and then toggled off the "Speed Limit" option. This option is only available in areas where turn-by-turn directions is supported, according to Apple, but if you want it gone, you want it gone.