You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
Are you using Joe Mode? I tried it and turned it off because I couldn't hear the beeps. I look out my windows to see how close I am anyway. I love the tech but don't trust it 100%
I'd say the best sensors are you're eyeballs. People used to be able to park without hitting anything, before all this technology but now we're depending on it too much.