The article assesses understanding and interpretation of scientific categories «reliability», «refusal», «congestion». The possibility of using the service level indicator as a criterion of reliability of functioning of street- road network is substantiated, bearing in mind that it reflects in a complex the data on economy, convenience and traffic safety, and through this, the state of a transport flow. Different approaches are given to determine the level of service, to classify features and

more »

... gns of the work performed. Further directions for improving reliability of highways, searching for the most variable indicator of reliability of the urban transport network are formulated. Keywords: street-road network, reliability, congestion, flow, failure, service level, time buffer, buffer index.