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

Application of Travel Time Data and Statistics to Travel Time Reliability Analyses: Handbook and Support Materials

List of Acronyms

ASD—aftermarket safety device

BSM—basic safety message

Caltrans—California Department of Transportation

ELPR—electronic license plate reader

FHWA—Federal Highway Administration

GIS—geographic information system

GPS—Global Positioning System

HCM—Highway Capacity Manual


LOS—level of service

LOTTR—level of travel time reliability

MAC—media access control

MAD—mean absolute deviation

MOE—measure of effectiveness

MTTI—mean travel time index

NCHRP—National Cooperative Highway Research Program

NPMRDS—National Performance Management Research Data Set

PeMS—performance measurement system

PM3—third performance management rule

PTI—planning time index

QC—quality control

RSU—roadside unit

SHRP 2—Second Strategic Highway Research Program

SR—State route

TMC—traffic message channel

TTI—travel time index

TTI50—median travel time index

TTI80—80th percentile travel time index

VHT—vehicle-hours traveled

VMT—vehicle-miles traveled