BTS | Table 1 - Summary of Data Analysis Adopted for the 1990 and 1995 NPTS

Table 1 - Summary of Data Analysis Adopted for the 1990 and 1995 NPTS

Description of constraints	1990	1995
Sample size-total trips	159,832	381,388
Reasons for dropping records
Invalid destination	3,314	43
Trip in miles >200	23,372	27,455
Travel minutes >120	3,015	5,254
Age >65 years	9,210	35,399
Age <18 years	21,470	63,832
Shop duration >420	707	70
Total dropped	61,088	132,053
Subtotal at trip level (after records are dropped)	98,744	249,335
Subtotal at person level	15,870	52,341
Travel + duration minutes >1,440	7,652	656
Travel + duration minutes <1,440	2,643	17,119
Duration <0	654	2,237
Total dropped	10,949	20,012
Net total at person level	4,921	32,329