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The City of Portland, Oregon

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Portland Bureau of Transportation

We keep Portland moving

Phone: 503-823-5185

Fax: 503-823-7576

1120 SW Fifth Ave, Suite 800, Portland, OR 97204

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Traffic Calming Glossary

An attempt to clarify language barriers that may develop between traffic calming professionals and the people they provide services to.

A  B  C  D  E  F  G   H  I  J  K  L  M

N  O  P  Q  R  S  T   U  V  W  X  Y  Z

A

ADT Average Daily Traffic - the total volume of traffic, combining both directions, using a street in a single 24-hour period.
   

B

BES Bureau of Environmental Services - Sewers and Storm Drains
BTED Bureau of Transportation Engineering and Design - Construction management section for Portland.
BTSM Bureau of Transportation System Management - the traffic management bureau of the Portland Office of Transportation.
BOM Bureau of Maintenance - Daily maintenance and repair of city streets, signs and signals.

C

CAC Citizen Advisory Committee - A committee of volunteers representing the public to advise City Bureaus regarding policy decisions.
CIP Capital Improvement Project - A project that spends money to make physical changes to the City's streets, sewers, etc.
CMAQ  Congestion Mitigation and Air Quality program - Part of the TEA-21 program to reduce pollution from auto traffic.

D

District Collector Street A traffic street classification under the Transportation Element of the City of Portland Comprehensive Plan.
   

E

85th Percentile Speed The speed that 85% of the traffic are traveling at or below.  Or, the speed that 15% of the traffic is traveling faster than.
   

F

   
   

G

   
   

H

HCT High Capacity Transit
HOV   High Occupancy Vehicle - A vehicle which is transporting more than one person.  The definition is variable depending on the severity of congestion to be mitigated, but usually means a vehicle with a minimum of 2 or 3 persons, or a motorcycle. HOV lanes (diamond lanes) are used to increase the number of people being transported without increasing the number of vehicles using a roadway.
   

I

ISTEA Intermodal Surface Transportation Efficiency Act - Former federal legislation to spend money from the transportation trust fund.  See TEA-21.
Impact Threshold A tool to help determine whether the "secondary" or unintentional diversion from a traffic calming project is acceptable.  The Impact Threshold Curve provides a guide based on traffic volumes measured on parallel streets before project construction.
   

J

JPACT Joint Policy Advisory Committee on Transportation - A 17-member committee of Metro which recommends transportation policies to the Metro Council.
   
   

K

   
   

L

LEV Low Emission Vehicle - A vehicle that produces small amounts of pollution.
LID Local Improvement District - A method for residents to make capital improvements to the streets they live on.   The most common way for unimproved streets to acquire curb and sidewalks.  The City finances the construction.  Costs are paid back by property owners through a special assessment over a 5 to 15 year period.
Local Service Street The lowest level of classification for traffic streets under the Transportation Element of the City of Portland Comprehensive Plan.
   

M

Major City Traffic Street A traffic street classification under the Transportation Element of the City of Portland Comprehensive Plan.
MPO  Metropolitan Planning Organization
MTIP Metropolitan Transportation Improvement Program - The Metro component of STIP,  which is a state list of transportation projects to receive state and federal funding in 4-year cycles.
MUTCD The Manual of Uniform Traffic Control Devices is a reference book of national guidelines used by traffic management professionals to install signs, pavement markings, traffic signals and design work zone traffic controls.

N

NA Neighborhood Association.  For information on Portland's neighborhood associations, visit the Office of Neighborhood Involvement.
Neighborhood Collector A traffic street classification under the Transportation Element of the City of Portland Comprehensive Plan.
   
   

O

OAR  Oregon Administrative Rules
ODOT Oregon Department of Transportation.   To visit their web site, click here ODOT.
   

P

Peak Hour The hour in which the most vehicles are counted passing a single point.   The peak hour can be directional, AM vs. PM, or combined.
PC Planning Commission, among other things.
PDOT Portland Office of Transportation - Plans, designs, manages construction and maintains public works assets of the City of Portland, including roads, sewers, storm drains, traffic management, traffic signals, street lighting, etc.  Click here for Portland's web site.
   
   

Q

   

R

Regional Trafficway A traffic street classification under the Transportation Element of the City of Portland Comprehensive Plan.
ROW Right-of-Way
RTP Regional Transportation Plan - The RTP is Metro's master plan for the region's transportation system. Metro is now revising the RTP. Metro is  the designated MPO for the Portland region, and has the responsibility of approving expenditure of federal transportation funds.

S

SDC S - A fee assessed to developers to pay for increases in transportation needs caused by that developer's project.ystem Development Charge
STIP State Transportation Improvement Program - A state list of transportation projects to receive state and federal funding in 4-year cycles.  See MTIP.
SWCP SW Community Plan
SWNI SW Neighborhoods, Inc. 

T

TAC  Technical Advisory Committee - A committee that evaluates technical aspects and advises city bureaus regarding policy decisions.
TAZ Transportation Analysis Zone
TE Transportation Element - The transportation portion of the City's Comprehensive Plan.  It outlines policy and goals regarding the movement of people and goods in Portland. Click to review the Transportation Element of the City of Portland Comprehensive Plan.
TEA-21 Transportation Equity Act for the 21st Century - Current federal legislation to spend money from the transportation trust fund.
TGM Transportation Growth Management
TOD Transit Oriented Development
TPR Transportation Planning Rule - Part of chapter 660 of the OAR. It implements the statewide planning goal 12 (transportation). It requires cities and states to have TSPs and requires certain connectivity, bicycle, and pedestrian improvements as part of development.
TSP T - Required by the TPR, this is the city's master plan for its transportation system. It includes plans for each mode of transportation, bike, pedestrian, motor vehicle, freight, transit, a financing plan, and a 20-year project list. The TSP must be finished within one year after Metro finishes the RTP.ransportation System Plan
   

U

UGB  Urban Growth Boundary
   

V

VMT Vehicle Miles Traveled - A measure of vehicle use.
Volume Traffic volume - The number of vehicles counted passing a single point.   Traffic volume is typically measured relative to a time period of 15 minutes, one hour, or 24 hours.

W

   
   

X

   

Y

   
   

Z

ZEV Zero Emission Vehicle - A hypothetical vehicle that does not produce pollution.  All vehicles contribute some emissions, whether through their use, manufacture or disposal.