Analyzing the effect of bus-stop spacing on air quality in urban areas using microscopic simulation: Howard Street case study (Maryland).

摘要

Spacing of bus stops is very important in any urban setting. When bus stops are closely spaced there is a disruption of existing traffic flow as buses stop for passenger services. This situation is predominant during rush or peak hour flow of traffic. The interruption of traffic flow results in energy loss, increased delay/congestion and an increase in mobile emission.; It is the intent of this thesis to show, using simulation, that proper spacing of bus stops can result in improved air quality in urban areas. The average bus stop spacing used by the Maryland Transit Administration (MTA) in downtown Baltimore is 137m, which varies from a nation wide survey that placed the average bus stop spacing at 330m, and a recent study determined the optimal bus stop spacing to be between 700m to 800m. This research also determined the average desirable bus stop spacing for the study area to be 330m using travel time and 350m when emission rate is considered.; This thesis shows that there is a significant change in emission rate during the peak hour or when there is an increase in traffic congestion and when using different traffic condition and bus stop spacing. The result obtained from a sensitivity analysis using 50% of the existing traffic condition shows the optimum bus stop spacing to be 350m without emission and 400m when emission rate is considered for the study area.