Awesome concept! Reminds me a lot of the game Dispatch. I liked how you had to plan whether to send single or multiple emergency vehicles, while deciding whether it was worth saving a near-timeout call. The pixel-art is simple, but coherent.
I did have some issues with controlling the vehicles. Often, they would ignore my inputs, or simply stop dead in their tracks. Aside from that, I think the game could use some visual feedback when you send trucks off. Maybe you could add some kind of dotted line showing where each of the trucks are heading, so I know for sure where they are headed.
Overall though, creative take on the theme with the main mechanic, and a great submission!