The time interval between consecutive vehicles traveling in the same direction on a specific route, usually measured in minutes. This interval helps determine the frequency of service, with shorter headways indicating more frequent service. Headways can be based on demand, such as during peak periods, or set by policy, such as every 30 minutes. Headways can be regular, clock, or ragged, depending on scheduling consistency. In some contexts, “headway” may also refer to a gap or missed vehicle in service.