About the Formula for Factoring Elastic Values

Factoring in elastic values of variables when performing demand forecasting can help determine future ridership.

Total Demand Forecast =

Base Demand Forecast +

Base Demand Forecast*Fare Level*Change In Fare Level)+

Base Demand Forecast*Service Frequency*Change In Service Frequency)+

Base Demand Forecast* Journey Duration *Change In Journey Duration)+

Base Demand Forecast* Reliability *Change In Reliability)+

Using the example shown in the previous sections, the following tables show what would be the resultant demand forecast (if service frequency is increased by 50%):
Vehicle Base Index Service Frequency Index Change In Service New Base Index
NOVEHICL

10

.2 .5 10 + (10*.2*.5) = 11
VEHICL_1 6 .5 .5 6 + (6*.5*.5) = 7.5
VEHICL_2 2 .75 .5 2 + (2*.75*.5) = 2.75
Data Field BDF Total Per Square Mile DF (Total)

NOVEHICL

11 2000 481 22000
VEHICL_1 7.5 3000 721 22500
VEHICL_2 2.7 1000 240 2700
Totals 47200*

*Change in demand after increase in service frequency= (47200-40000)/40000*100 = an increase in demand of 18%