traveltimes

Travel time is the duration required to move from a starting point to a destination along a specified route within a transportation network. It is a key metric used in transportation planning, logistics, and navigation. Travel time can refer to point-to-point travel time for a single trip, or to network-wide estimates used in planning models. Free-flow travel time represents the minimum possible duration under uncongested conditions, while actual travel time includes delays caused by congestion, incidents, or other disruptions.

Actual travel times vary by time of day, day of week, season, and local conditions. Primary drivers include traffic density, incidents (accidents, breakdowns), road works, weather, and special events. Driver behavior, vehicle mix, and route choice also influence travel times. In public transit, wait times and schedule adherence affect total door-to-door travel time. Because conditions change and networks are interconnected, travel times are inherently variable and forecast error is common.

Travel times are measured from data sources such as roadway sensors, GPS traces, probe data from smartphones or connected vehicles, and transit schedules. Common metrics include average or median travel time, as well as reliability measures like the travel time index, which compares peak-period travel time to free-flow time, and percentile-based metrics (for example, the 95th percentile). Models range from macroscopic and mesoscopic network models to microscopic simulations, and can be used for real-time routing or long-range planning.

Applications include traffic management, urban and regional planning, logistics optimization, and consumer navigation. Limitations include data privacy concerns, sampling bias, measurement errors, and the challenge of capturing highly variable conditions in forecasts. Effective use often requires combining multiple data sources and validating models against observed travel times.

See also: travel time reliability, travel time index, travel time prediction, and congestion pricing.