IN THIS PAPER, WE FIRST EXPLAIN HOW TO CALCULATE AVERAGE TRAVEL TIME BETWEEN TWO REGIONS WHICH HAVE TWO KINDS OF TRANSPORTATION （SLOW AND HIGH SPEED) - FOR EXAMPLE, ON FOOT AND USING TRAIN, OR ORDINARY ROADS AND EXPRESSWAY. WE USE RECTILINEAR DISTANCE FOR MOVEMENT OF SLOW SPEED TRANSPORTAION. SECONDLY, WE CALCULATE AVERAGE TRAVEL TIME IN A REGION WITH GRID-PATTERN RAILWAY NETWORK. LASTLY, USING AVERAGE TRAVEL TIME, WE EVALUATE MEANS OF TRANSPORTATION FOR THEIR SPEED AND NETWORK DENSITY.
