The number of large scale condominium construction projects had dramatically
increased in Bangkok. Many projects had occurred in either densely populated areas or
in central business districts, where traffic conditions were usually highly congested. To
prevent traffic problems, a traffic impact study must be prepared and submitted for
review by concerned public authorities. Unit trip generation rates were important data
in traffic impact analysis. Without accurate unit trip generation rates, public agencies
could not obtain accurate information on the traffic that will be generated. This study
aimed to study trip rates and the factors affecting them for condominium construction
project in Bangkok. The data were collected from 30 condominium construction sites
located in 15 districts of Bangkok. The analysis used the linear regression method and
was divided into three cases: 1) trip rates for all vehicles, 2) trip rates for classified
vehicles, and 3) trip rates for all types of condominium. All case analyses considered
weekdays, Saturday, and Sunday. The results found that trip rates related to the number
of dwellings in the condominium. The trip rates for all vehicle types on weekdays,
Saturday, and Sunday were 10.636, 4.647, and 9.294 vehicles per 100 dwelling units
per day respectively. The trip rates for six-wheeled and ten-wheeled trucks on
weekdays, Saturday, and Sunday were 2.046, 0.975, and 0.575 vehicles per 100
dwelling units per day respectively. The trip rate for four-wheeled trucks and passenger
cars on weekdays was 1.960. Regarding condominium types, the trip rate for low rise
condominiums for all vehicle types on weekdays was 5.315 while the trip rates for high
rise condominiums for weekdays, Saturday, and Sunday were 3.965, 2.667, and 1.261
respectively.