Travel Time Reliability: Making It There On Time, All The Time

Long Description for Figure 3

This figure shows a line chart of the travel time index and planning time index by time of an average day for citywide conditions in Los Angeles. The line representing the travel time index has two peaks that correspond with the morning and evening peak traffic times. The line representing the planning time index tracks a similar trend, but has much high index values. This is because the travel time index approximates the 50th percentile of travel conditions, whereas the planning time index represents the 95th percentile. The space between the planning time index and the travel time index is identified as the "buffer between the expected (avg.) and 95th percentile travel times."

Figure 3. Reliability measures compared to average congestion measures

Source: Mobility Monitoring Program, http://mobility.tamu.edu/mmp/.