Travel time reliability is an important system performance measure for freeway traffic operations. It captures the variability experienced by individual travelers, and it is an indicator of the operational consistency of a facility over an extended period. Real-life transportation data were used to develop a new methodology for estimating travel time reliability of the I-4 corridor in Orlando, Florida. Four different travel time distributions were tested: Weibull, exponential, lognormal, and normal. The developed best-fit statistical distribution (lognormal) can be used to compute and predict travel time reliability of freeway corridors and report this information in real time to the public through traffic management centers. When compared with existing Florida and buffer time methods, the new reliability method showed higher sensitivity to geographical locations, which reflects the level of congestion and bottlenecks. Another advantage of the new method is its ability to estimate the travel time reliability as a function of departure time.
Congestion on freeway facilities is a growing menace. Interstate 4 (I-4) in the Central Florida region has been experiencing delays during peak hour; this has warranted research on traffic management strategies. The public, through the media, had proposed removing tolls on state toll roads to divert traffic from I-4. A microsimulation model, Paramics, was used to examine the potential impact of this proposal. SR-417 is a relatively uncongested toll road alternative to I-4. SR-528 is the east–west toll road connecting SR-417 and I-4. Commuters on SR-417 have to travel 15 mi longer and pay $5 compared with no monetary cost on I-4 for the same trip. The public and politicians are reluctant to toll I-4 to relieve congestion. The results from the simulation indicated that under recurring congestion conditions on I-4, removing tolls on SR-417 and SR-528 would not divert enough traffic from I-4 because of the 15-mi advantage. Under incident and lane closure scenarios on I-4 with toll reduction on SR-417 and SR-528, the travel time would increase on I-4. This result would prompt some diversion, with volumes and travel times increasing on SR-417. It was concluded that the amount of traffic that would be diverted from I-4 to the toll roads would not significantly relieve congestion on I-4. When specific origin–destination pairs were analyzed, average travel time savings on I-4 were only around 5 min. It was concluded that contrary to the media and public perception, toll reduction would only have a minimum impact on reducing I-4 congestion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.