Safety Performance Measures for Priced Managed Lane Facilities

Authors

Cecilia Fabian Kadeha, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Civil Engineering

First Advisor's Name

Dr. Priyanka Alluri

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Dr. Albert Gan

Second Advisor's Committee Title

Committee Co-Chair

Third Advisor's Name

Dr. Mohammed Hadi

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Dr. Xia Jin

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Dr. Thobias Sando

Fifth Advisor's Committee Title

Committee member

Sixth Advisor's Name

Dr. Wensong Wu

Sixth Advisor's Committee Title

Committee member

Keywords

Highway Safety, Managed Lanes, Safety Performance performance, Crash modification factor

Date of Defense

3-29-2023

Abstract

Managed lanes are increasingly considered an effective strategy to alleviate congestion, especially in urban areas with limited right-of-way, environmental concerns, policy issues, and high construction costs. Managed lanes usually operate adjacent to the general-purpose lanes on freeway facilities. The separation treatments between the managed lanes and the general-purpose lanes include painted pavement lines (single, double, dotted, or solid), barriers such as concrete or tubular delineators (commonly referred to as pylons), or wide separations with a median between the managed lanes and the general-purpose lanes. Safety performance has rarely been discussed in the literature. Most studies have focused on planning, design, toll pricing, policies, environmental factors, Intelligent Transportation System (ITS) infrastructure, and mobility impacts (e.g., travel time reliability).

This dissertation aimed to develop Safety Performance Functions (SPFs) and Crash Modification Factors (CMFs) for freeway facilities with managed lanes. Data were collected from 68.9 miles of freeway segments in California, Florida, Texas, and Washington State. Seven separate crash models were developed based on the crash severity, i.e., fatal and injury, property damage only, and the number of vehicles, i.e., single-vehicle and multi-vehicle crashes.

Results show that the average lane width was significant for single-vehicle and multi-vehicle PDO crash types, indicating a negative relationship to the crash frequency with CMF values of 0.86 for both crash types. Increasing the number of managed lanes showed a consistent reduction of crashes by up to 22%, as shown in CMF values of 0.78 for total and PDO crashes and 0.8 for FI crashes. Having pylons as a separation treatment between managed lanes and the general-purpose lanes yielded CMF values of 1.71 for total crashes, 0.72 for FI crashes, and 1.71 for PDO crashes. This implies that the frequency of PDO crashes is higher with pylon separation compared to having painted lane markers separating the managed lanes from the general-purpose lanes. The developed crash predictions are essential for the network screening process, developing countermeasure comparison, and project evaluation. Agencies could use the models to make decisions and conduct benefit-cost analyses when planning to deploy managed lanes on freeway facilities.

Identifier

FIDC011090

Recommended Citation

Kadeha, Cecilia Fabian, "Safety Performance Measures for Priced Managed Lane Facilities" (2023). FIU Electronic Theses and Dissertations. 5242.
https://digitalcommons.fiu.edu/etd/5242