Upon hearing that speed cameras are supposed to be improved soon I have compiled the following list of ideas:

• full text announcement ("warning, speed camera in x meters")

• a banner that displays the distance to the camera and the allowed max speed

• a larger icon drawn on the map

• an icon that also displays the allowed speed

• showing speed cameras as an icon on the map even when user isn't in navigation mode

• displaying not only speed cameras but also red light cameras and height control cameras

See screenshots for examples on how to render the icon on the map