Variable Speed Limit: A Microscopic Analysis in a Connected Vehicle Environment

Date
2016
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Abstract
This thesis presents a novel proactive Variable Speed Limit (VSL) control algorithm to find a balanced trade-off among mobility, safety and environmental impact in a Connected Vehicle (CV) environment. The development of CV technology has the potential to provide essential data at the microscopic level to have an understanding of real time drivers' behavioural information. CVs also have the unprecedented ability to be used as mobile sensors able to capture the impact of control schemes on driver’s behaviour and compliance rate. In addition, Connected/Autonomous Vehicle initiatives claim to serve three main purposes: improving safety, enhancing mobility and reducing emissions. In line with these initiative, this thesis develops a dynamic anticipatory VSL control strategy that attempt to meet the multi-criteria objective of improving travel time, safety, and emission/fuel consumption, while taking into consideration the likely responses of drivers. A microscopic car following model, IDM (Treiber et al., 2000) in conjunction with a microscopic lane changing model, MOBIL (Treiber and Kesting, 2009) are used to anticipate the lane changing and acceleration/deceleration decisions of drivers on multi-lane freeway. A system-wide optimization using a multi-objective function is formulated to obtain the VSL values that minimize: (i) Total Travel Time (TTT); (ii) Collision probability derived from Time to Collision (TTC); and (iii) Emission and/or Fuel Consumption. The proposed algorithm has been optimized using Genetic Algorithm(GA) via an integrated VISSIM-COM-MATLAB interface. The results of the thesis suggested that the VSL strategies were able to result in fewer lane changing rate (LCR), which synchronized driver behaviour. Also, the developed algorithm was able to produce a smoother acceleration and deceleration pattern compared to the uncontrolled case, which corresponds to lower emission and fuel consumption. The sensitivity analysis results showed that at free flow condition, the VSL strategy outperformed the uncontrolled case up to 35% penetration rate. However, for higher demand levels, the safety component was highly sensitive to variation in % of CV and required more weight than the mobility and sustainability components. The result also indicated that 35% CV penetration rate was the minimum rate required to realize improvements in terms of safety, mobility and environmental improvements.
Description
Keywords
Sociology--Transportation
Citation
Khondaker, B. (2016). Variable Speed Limit: A Microscopic Analysis in a Connected Vehicle Environment (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/28631