I'm creating a service area for schools and libraries in Maine and came across some issues when trying to use Drivetime/Traveltime as the impedance. I've gotten simple distance to work using multiple breaks but the time field does not want to work and/or throws one big polygon around my study area.
In the roads layer attribute table, I've created three new fields:
shape_length -> shape_miles (meters to miles conversion)
shape_miles_mph (dividing shape length in miles by the speed limit to get the decimal of an hour to traverse each road segment)
shape_miles_mph_x60 (multiplying the decimal of an hour field to convert to minutes)
First, is this setup step necessary to using traveltime as my impedance break?
Second, are there any other steps I've forgotten which make this analysis run smoothly?
Any help would be great as this is getting pretty frustrating.