The effects of bus priority on the delay and emissions of busses and the other vehicles : a Copenhagen case study

Goinga, Y.W.A. (2015) The effects of bus priority on the delay and emissions of busses and the other vehicles : a Copenhagen case study.

Abstract:To keep up with the rapid and expanded urbanization solutions as traffic management and intelligent traffic solution is needed. Public transport can be essential to reduce traffic congestions, but it needs to be more competitive. One option to make the bus more attractive is bus priority, as it is expected to make the bus more predictable and reduce the travel times. The city of Copenhagen wants to implement bus priority. Before implementing it throughout the city, Copenhagen wants to know what the effects will be. To determine the effects two options are used: testing the implementation on the street and doing a simulation study (= this research). In 2014 a previous study about the effects of bus priority was conducted on the same network. However the previous study used a different traffic light configuration. This study will use the configurations as they will be implemented on the streets and thus will this study also show the effects that can be expected. Besides small changes to be capable to run the configuration, also small changes to make the network up to date were performed. Vissim is used for the simulation of the 21 intersections in downtown Copenhagen. These 21 intersections are part of the 1a bus route, also lines 2a, 9a & 40 follow half of the testing network. Among the results of this network will be the average delay and emissions during peak hour (08.00-09.00) and off-peak hour (12.00-13.00). Both time periods will be run 10 times (5 times without bus priority to create a baseline and 5 times with bus priority). Comparing the median runs with each other the following results were found: during peak hour the average delay of busses decreased by 3,00% against an increase of all vehicles by 1,63% (mainly caused due to the strong increase of the average per vehicle for bikes 8,57%). Off-peak hour showed an improvement of 5% for the average delay per vehicles of all vehicle classes, except the average delay time per vehicle of busses (+5,71% probably caused by outliers in the small number of HGVs). Results of emissions were only made on network level and showed a small decrease (around the 1%) of emissions for all classes but the HGVs (+2,5%). The results found during this study are less than the improvement of 3-10% found during the previous study, but configuration and priority were completely different. Therefore, since only pre start and extension are allowed during the runs conducted during this study, the results found for the network are better than expected. Looking at the delay on bus route scale: the results are different for every route, but in general show a positive effect of bus priority. The bus line (1a) shows better results than the lines which are only going through the bottom half of the testing network. The results of the intersections are also completely different for all the intersections: during peak hour on 50% of the intersections the bus benefits and during off-peak hour the bus benefits in 70% of the cases bus priority is implemented. To determine what causes the different effects two analysis were performed: correlation and ANOVA. The only interesting correlation found is the relation between the average delay of all the vehicles and the average delay of the motorized vehicles. ANOVA showed a relation between the number of motorized vehicles and the effect of bus priority (bus priority has a better effect, on the average delay of busses, on intersections with less motorized vehicles. Before Copenhagen can use the results from this study, comparing more runs with each other or running more runs so the mean can be used. But in general the results of this study are a good start for the recommendation of implementing bus priority (on certain intersections).
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering BSc (56952)
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