With increasing traffic congestion, travel time reliability is becoming an important measure for travelers and freight shippers to plan trips. While adding lanes to increase highway capacity may be very expensive, transportation agencies can provide travel time information to customers at a relatively minimal cost. The Washington State Department of Transportation has initiated an innovative program to achieve this goal (WSDOT). This information can take various forms, and different methods can be employed to improve travel time itself. This thesis presents WSDOT's travel time reliability program as a case study. Data on speeds from Pennsylvania are then analyzed to better understand how one measure of travel time reliability, the 95^th percentile travel time, varies by time of day and day of the week. Finally, the thesis explains the applicability of travel time reliability as a performance measure to be used in decision-making. Travel time reliability should certainly be a measure in a transportation agency's goal of improved customer service.