Office of Operations
21st Century Operations Using 21st Century Technologies

Recurring Traffic Bottlenecks: A Primer
Focus on Low-Cost Operational Improvements (Fourth Edition)

List of Abbreviations and Symbols

AASHTO – Americans Associated of State and Highway Transportation Officials

ARM – Annual Reliability Matrix

ATM – Active Traffic Management

BII – Bottleneck Intensity Index

Caltrans – California Department of Transportation

CBI – Congestion and Bottleneck Identification

CDOT – Colorado Department of Transportation

CLT – Contraflow Left Turn

CMAQ – Congestion Mitigation and Air Quality

CMP – Congestion Management Process

COBRA – Colorado Bottleneck Reduction Assistance

CSMP – Corridor System Management Plan

DCD – Double Crossover Diamond

DDI – Diverging Diamond Interchange

DE – Design Exception

DJC – Dynamic Junction Control

DLG – Dynamic Lane Grouping

DLM – Dynamic Lane Merge

DLT – Displaced Left-Turn

DOT – Department of Transportation

DRLT – Dynamic Reversible Left Turn

FDOT – Florida Department of Transportation

FHWA – Federal Highway Administration

GP – General Purpose

GPS – Global Positioning System

HEP – Hazard Elimination Program

HOT – High Occupancy Toll

HOV – High Occupancy Vehicle

HSIP – Highway Safety Improvement Program

HSP – Highway Safety Program

HSR – Hard Shoulder Running

ITRE – Institute for Transportation Research and Education

ITS – Intelligent Transportation Systems

LBR – Localized Bottleneck Reduction

MnDOT – Minnesota Department of Transportation

MOPAC – Missouri and Pacific

mph – Miles Per Hour

MPO – Metropolitan Planning Organization

MTTI – Mean Travel Time Index

MUT – Median U-turn

NAAQS – National Ambient Air Quality Standards

NPMRDS – National Performance Management Research Data Set

ODOT – Ohio Department of Transportation

pcphpl – Passenger Cars Per Hour Per Lane

PDO – Property Damage Only

PDSL – Priced Dynamic Shoulder Lane

PennDOT – Pennsylvania Department of Transportation

PTI – Planning Time Index

QR – Quadrant Roadway

RCUT – Restricted Crossing U-Turn

RIDOT – Rhode Island Department of Transportation

SHA – State Highway Agency

SHSP – Strategic Highway Research Program

SIP – Statement Implementation Plan

STARS – Strategically Targeted Affordable Roadway Solutions

STM – Spatiotemporal Matrix

TCP – Traffic Control Plan

TDM – Travel Demand Management

TIM – Traffic Incident Management

TIP – Transportation Improvement Plan

TMC – Traffic Management Center

TSMO – Transportation Systems Management and Operations

TTI – Travel Time Index

TxDOT – Texas Department of Transportation

V/C – Volume/Cost

VDOT – Virginia Department of Transportation

VHT – Vehicle Hours of Travel

VMT – Vehicle Miles of Travel

VPL – Vehicles Per Lane

WSDOT – Washington State Department of Transportation

WTP – Washington Transportation Plan

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