This study evaluates electric automated vehicle deployment scenarios in suburban areas, using Grorud Valley in Norway as a case study. It aims to determine the best deployment scenario compared with the current situation. Four scenarios were evaluated for global warming potential, air pollution emissions, and accidents. Each parameter was weighted with an external cost factor to calculate the aggregated total external costs for each scenario. This study revealed that electric automated vehicles with ridesharing integrated into Mobility-as-a-Service networks yielded the best results. With 100% market penetration, external costs can be reduced by 66%, and even with 30% market penetration, they can be reduced by 20%. Climate change costs were the main contributors, accounting for more than half of the costs in all scenarios. Although introducing automated vehicles in combination with public transport and ridesharing in a Mobility-as-a-Service concept helps reduce external costs, most of the benefits are derived from the electrification of the vehicle fleet and not from the new mobility concept.