Dave - what a great, thoughtful post! I have to say, I never really thought about <em>why</em> I pulled over for ambulances, fire trucks, etc. I just always did it because that's what I was taught to do and because I knew it was the right thing to do. It's pretty incredible and a bit humbling to make the connection to the larger issue of subconsciously caring about other people. 

The more I think about it, the more I think the sirens are also telling us to "slow down" - literally and figuratively. Slow down, take the time to let others go before you and find pleasure in the simple things in life. Like, as you mentioned, the crickets.