In the context of digital road networks, lane-level data support and dynamic traffic perception enable the precise calculation of operational parameters for different lanes during various time periods. Delay metrics play a crucial role in evaluating traffic states. The delay time index defined in this paper intuitively reflects traffic delay states and eliminates the influence of network scale on delay assessment, making it an appropriate evaluation metric. By establishing relationships among the indices at different levels of the road network through weighting, and considering factors such as traffic flow and free-flow travel time, this paper presents definitions and calculation methods for the weight coefficients of various evaluation objects within the network. Based on the constructed weight system, a multi-scale delay time index calculation method based on weight coefficients is derived. Case results indicate that the traffic states evaluation metrics obtained through weight coefficient estimation are consistent with those derived from simulation and defined calculations. Additionally, when the data acquisition rate for the road network is 10%, the relative accuracy of the estimates can reach 96.0% at an 80% cumulative probability. Utilizing foundational operational data provided by digital road networks, not only enables the step-by-step calculation of the delay time index across multi-spatial scales of the road network, but the overall traffic states of the network can also be estimated based on partial traffic operation data, effectively supporting the assessment needs of the overall traffic states of the network in scenarios where the digital road network construction is incomplete or coverage is insufficient.