green roads are approved - blue roads are NOT approved by ISO
some streets are straight and level - maybe 60 MPH
some roads are very curvy - probably 30 MPH roads
which poses an interesting question - how accurate are ISO ratings? 30
mph roads vs 60 mph roads can change response times by 200% - 2 minute
turnout times vs 5 minute turnout times can change overall response
times up to 300%