The concept of decision making has emerged in many studies but is rare in ETC system selection by Road Department administrations. Existing road equipment procurement documentation shows this decision making is not structured and does not use a clear methodology. Based on China's road characteristics, this study attempted to find the decision-making factors, and integrate the decision elements into a decision model. This research demonstrates three toll road construction projects in the real world. Sensitivity analysis was used to find the influence of decision factors on optimization.

The literature review indicated ETC systems selection belongs to a multi-criteria decision-making group, who will choose a suitable system to best satisfy Road Department administrations. This decision making should have three basic elements in accordance with the multi-criteria characteristics: 1. Requirements of Road Department administrations; 2. The performance of the ETC system; 3. Criteria for measuring system performance under the requirements.

In the process of decision-making model development, both quantitative and qualitative approaches have been used as information collection, to collect useful information of the decision elements. Objective methods are used for performance evaluation and criteria weighting. Finally, the decision-making model was designed for constraint and optimization.

The main contribution of this study is to prove the decision-making activities of decision makers, including data collection, decision goal setting and performance evaluation, which can be classified, summarized and modelled, and that the overall decision-making model established in this research can be fully utilized in this field, within theoretical consistency and the universality of road application. The conclusion of this study is that decision making is a necessary activity for road department administrations to choose an ETC system under China’s road environment and road policies.

The second contribution of this study is to establish a method and theory framework for building decision models in this field. This is accomplished by collecting the elements of decision making, obtaining the requirements of Road Department administrations, and establishing performance evaluation. The demonstration work proved that under the current road environment and policies in China, different road projects have produced consistent decision-making results, which indicated that the decision outcome is suited to running in China’s road environment.