Human Factors Guidelines for Road Systems: Third Edition (2025)
Chapter: 31 Abbreviations
CHAPTER 31
Abbreviations
Δt | sampling interval |
AARP | American Association of Retired Persons |
ABS | anti-lock braking system |
ADT | average daily traffic |
APL | arrow-per-lane (sign) |
APS | accessible pedestrian signals |
ASD | available sight distance |
ATIS | Advanced Traveler Information Systems |
BCT | bicycle crossing time |
BD | braking distance |
BMG | bicycle minimum green time |
BRT | base reading time |
Caltrans | California Department of Transportation |
cd | candela |
CIE | Commission Internationale de lʼEclairage |
cm | centimeter(s) |
CMF | crash modification factors |
CMS | changeable message signs |
CPM | crash prediction model |
CSS | context sensitive solutions |
DPM | driver performance model |
DSD | decision sight distance |
DVRE | driver, vehicle, roadway, and environment |
EL | edge lines |
FARS | Fatal Accident Reporting System |
FYA | flashing yellow arrow |
HFG | Human Factors Guidelines |
HFIM | Human Factors Interaction Matrix |
HFST | high-friction surface treatment |
HOV | high-occupancy vehicle |
HPS | high-pressure sodium (lamp) |
IA | Intersection angles |
IHSDM | Interactive Highway Safety Design Model |
ISD | intersection sight distance |
ITE | Institute of Transportation Engineers |
ITS | Intelligent Transportation System |
km/h | kilometers per hour |
LBI | leading bicycle interval |
LC | lane change |
LD | legibility distance |
LED | light-emitting diode |
LongROAD | Longitudinal Research on Aging Drivers |
LOS | level of service |
LPI | leading pedestrian interval |
LPS | low-pressure sodium (lamp) |
m | meter |
mcd | millicandela |
MH | metal halide |
mi | mile |
mi/h | miles per hour |
mm | millimeter |
MMI | most meaningful information |
MT | maneuver time |
MUTCD | Manual on Uniform Traffic Control Devices |
NACTO | National Association of City Transportation Officials |
NHTSA | National Highway Traffic Safety Administration |
N•m | newton meter |
NMSL | National Maximum Speed Limit |
NTOR | no turn on red |
PATH | Partners for Advanced Transit and Highways |
PC | point of curvature |
PCC | Portland cement concrete |
PHB | pedestrian hybrid beacon |
PIEV | perception-identification-emotion-volition |
PMD | post-mounted delineator |
POV | principal other vehicle |
PPE | personal protective equipment |
PRT | perception-reaction time |
PSD | passing sight distance |
PVSD | preview sight distance |
R value | correlation-coefficient |
ROW | right-of-way |
RPM | raised pavement marker |
RRFB | rectangular rapid flashing beacon |
RPM | raised pavement marker |
RRPM | raised retroreflective pavement marker |
RT | reaction time |
RTOR | right turn on red |
s | second(s) |
SAE | Society of Automotive Engineers |
SBBL | shared bus-bicycle lanes |
SCL | speed-change lane |
SD | sight distance |
SDHAZ | sight distance to hazard |
SF | safety factor |
SI | International System of Units |
SLIDE | simplified location of information deficiencies |
SPD | spectral power distribution |
SR | sampling rate |
SRS | shoulder rumble strip |
SSA | Safe System Approach |
SSD | stopping sight distance |
SV | subject vehicle |
SVROR | single vehicle run off road |
TBL | through bicycle lane |
TCD | traffic control device |
TER | truck escape ramp |
TWLTL | two-way left turn lane |
USSC | United States Sign Council |
UVC | Uniform Vehicle Code |
v/c Ratio | volume-to-capacity ratio |
VMS | variable message sign |
VPD | vehicles per day |
vph | vehicles per hour |
VRU | vulnerable road user |
VSL | variable speed limit |
VTTI | Virginia Tech Transportation Institute |
WSS | weight-specific-speed |
