Singly constrained Gravity ModelTrip Distribution

FAQs

• When to use origin constrained and destination constrained model?
  Origin constrained model can be used when sum of all the trips attracted to all the attraction zones will be equal to the total number of trips produced in a production zone. Mathematically: $$\nonumber \sum \limits_{j} T_{ij} = O_{i}$$
  Destination constrained model can be used when sum of trips produced for all the trip production zones will be equal to the number of trips attracted to a destination zone. Mathematically: $$\nonumber \sum \limits_{j} T_{ij} = D_{i}$$
• What is Travel Impedance? Travel Impedance is known as generalized cost for travel. Travel impedance of generalized cost is a function of in-vehicle-travel-time, waiting time, fare, discomfort level, transfer time, walk time etc.