According to NCHRP Report 493, there are five major left turn signal indications for permitted operations in the United States. They are: Circular Green (CG), Flashing Circular Red (FCR), Flashing Red Arrow (FRA), Flashing Circular Yellow (FCY) and Flashing Yellow Arrow (FYA). The main goal of this thesis is to study the driver behavior and analyze safety of drivers for different left turn indications using a real-time driving simulator. Different signal indications alter driver behavior which influences velocity and acceleration profiles. These profiles influence vehicular emissions and hence need to be studied as well. For this purpose, different scenarios are implemented in the driving simulator. Data is analyzed using Microsoft Excel, JMP Statistical tool and MATLAB. Safety of drivers is analyzed with respect to the parameter "Time to Collision (TTC)" which is directly obtained from simulator data. Vehicular emissions and fuel consumption are calculated using VT-Micro microscopic emissions model. Graphs are plotted for TTC and total emissions. Results indicate that for a day-time scenario, FCY and FYA are the most suitable left-turning indications whereas FCR and FRA are most suitable for a night-time scenario. / Master of Science / There are five major left-turn indications for permitted operation in the United States. They are: Circular Green (CG), Flashing Circular Red (FCR), Flashing Red Arrow (FRA), Flashing Circular Yellow (FCY) and Flashing Yellow Arrow (FYA). Different states use different left-turn indications throughout the country. The level of driver comprehension for a particular signal indication will have an effect on the driving behavior and this in turn will affect fuel consumption and total emissions. The main goal of this thesis is to study driver behavior for different left-turning operations and to provide guidelines for the selection of signal indications. For this purpose, a real time driving simulator is used and different scenarios are implemented for left-turning operations. Data has been collected from the simulator to analyze driver safety in each scenario. Velocity and acceleration data from the simulator is used to calculate vehicular emissions to analyze environmental impact. The signal indication that best suits a given situation should provide maximum driver safety and minimum environmental impact. Graphs are plotted and results indicate that, during day time FCY and FYA are the most suitable indications whereas FCR and FRA are best suited for a night time scenario.