Graduation Year

2008

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Civil Engineering

Major Professor

Jian Lu, Ph.D.

Keywords

Freeway management, Emergency planning, Reverse laning

Abstract

This dissertation evaluates contraflow during a hurricane evacuation for grade separated highways. Contraflow is the concept of reversing the typical direction of highway travel to provide more outbound roadway capacity. The State of Florida has spent more time and resources towards the planning and the designing of potential contraflow facilities than any other state in the country; however, contraflow has yet to be implemented (as of Summer 2008). This study determines if the additional capacity benefits of contraflow outweigh the logistical requirements of implementing contraflow. Five different alternatives of contraflow lane configurations were comparatively evaluated. The format of this study is unique due to the evaluation of both capacity and logistical measurements. Each alternative was subject to evaluation of six different performance measures.

The six different performance measures consisted of improved capacity, speed variation, logistics, required personnel, required infrastructure, and delay/congestion. Each performance measure was evaluated using a scaled scoring system. The alternative with the lowest average scoring among the different performance measures was considered the best alternative. Contraflow should only be considered as a last resort. The loss of inbound access, safety concerns,logistical requirements, and the additional strain of public resources during an evacuation are negative aspects that should be considered when determining the capacity benefit. If extenuating circumstances justify contraflow, then a full conversion of all inbound lanes to outbound lanes, known as Alternative D, should be considered. This alternative demonstrated the greatest capacity benefit while requiring the least amount of public resources.

However, instead of contraflow, it is suggested to divert public resources towards other, more practical alternatives. Real time traffic monitoring has been demonstrated to be quite useful. Publicly accessed web-pages on the internet and the recent installation of variable message signs all provide improved notification of traffic conditions and of the capability to use alternative "atgrade" evacuation routes in addition to using the grade separated highways. This driver notification and the ability to ensure the safe and efficient travel on these alternative routes may be worth further investment, as well as being a potential topic of future research.

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