Travel Time Reliability: Planning Time Index
Travel times vary greatly from day to day, and travelers remember those few bad days they suffered through unexpected delays. Travel time reliability measures the extent of this unexpected delay. Planning time index (PTI) represents the additional time that a traveler should budget to ensure on-time arrival 95% of the time. Different from on-time arrival, the higher the PTI, the worse the reliability is.
Different from on-time arrival, the higher the PTI, the worse the reliability is. In 2019, the PTI on Florida’s freeways during peak hour stayed at 1.53. The traveler needs to plan 15.3 minutes 95% of the time with a 1.53 PTI. The peak hour PTI went up from 1.48 in 2015 to 1.53 in 2019.