How to merge this two layers

[LinaVidman]

I have made an map where I can see respone times for the fire truck, I did it in service area of network analysis, and made one for helicopter with buffer tool. In the attribute table have i add field like minutes, speed and distance. 

My problem now is how I should do to merge this to layer to one where I can see if the helicopter or the fire truck is fastest to each pixel. I want it in a layer there it shows in two diffrent color.

Or is there another way I should have done the last maps to create this map.

 

Hope someone understands what I mean and can help me

/ Lina