PURPOSES : The purpose of this study is to review a method to estimate the average travel speed of the Bus Rapid Transit(BRT) section using the bus departure and arrival time data collected using the Korean bus information system (BIS). METHODS : To determine an average travel speed estimation model suitable for the BRT system in Korea, the speed estimated using the speed estimation model of TCQSM, which is used in the U.S., and that using the proposed speed estimation model that used the bus departure and arrival time data were compared with the actual travel speed using a t-test. RESULTS : The average travel speed estimated using the proposed method was more suitable for the actual average travel speed than that estimated using the TCQSM model. CONCLUSIONS : As a result of estimating the average travel speed, if the length of the link is 900 m, SBRT can be constructed on the existing road, but at least 1,200 m must be ensured to build SBRT in the new city. The proposed bus average travel speed estimation model can be used to review the BRT operational efficiency considering the speed limit, traffic signal, and dwelling time at bus stops in the planning and operation stages of the BRT.

PURPOSES : Two-lane highways have one lane in each direction, and lane changing and passing maneuvers take place in the opposing lane depending on the availability of passing sight distance. 2001 Korea Highway Capacity Manual (KHCM) is classified into two classes of two-lane highways (Type I, II), and average travel speed and time-delayed rate are used as measures of effectiveness (MOEs). However, since existing two-lane highways have both uninterrupted and interrupted traffic flow-system elements, a variety of free-flow speeds exhibits in two-lane highways. In addition, it is necessary to check if the linear-relationship between volumes and time-delayed rate is appropriate. Then, this study is to reestablish the relationship between average travel speed, time-delayed rate, and flow. METHODS : TWOPAS model was selected to conduct this study, and the free-flow speeds of passenger cars and the percentage of following vehicles observed in two-lane highways were applied to the model as the input. The revised relationships were developed from the computer simulation. RESULTS : In the revised average travel speed vs. flow relationship, the free-flow speed of 90km/h and 70km/h were added. It shows that the relationship between time delayed-rate and flow appeared to be appropriate with the log-function form and that there was no difference in time-delayed rate between the free flow speeds. In addition to revise the relationships, the speed prediction model and the time-delayed rate prediction model were also developed. CONCLUSIONS : The revised relationships between average travel speed, time-delayed rate, and flow would be useful in estimating the Level of Service(LOS) of a two-lane highway.