ARLINGTON COUNTY, VIRGINIA
NEIGHBORHOOD TRAFFIC CALMING COMMITTEE

#1 COURTHOUSE PLAZA, SUITE 717
2100 CLARENDON BOULEVARD
ARLINGTON, VIRGINIA 22201
(703) 228-3681

January 18, 2000

Dear Advisory Group Member:

I am pleased to enclose a copy of the report describing the proposed Neighborhood Traffic Calming Program for your review and comment. This report represents the work of the Neighborhood Traffic Calming Committee (NTCC) that was appointed last year by the County Board to develop a process and criteria for implementing traffic calming measures that can be considered to address traffic problems on neighborhoods streets. The report will be considered by the County Board on March 11, 2000.

The advisory group on which you serve will consider this item in the near future, and I want to provide plenty of time for your review of the report. The dates for consideration of this report by the various advisory groups are indicated below:

Planning Commission on January 31 at the 7:00 p.m. 'pre-meeting"

Arlington County Civic Federation on February 1

Neighborhood Conservation Advisory Committee (NCAC) on February 10

Transportation Commission on February 16.

Should you have questions about the report, please feel free to call Jeff Sikes, NTCC staff coordinator, at (703) 228-3696. Thank you for cooperation and interest in this important program to make Arlington's neighborhood streets safer and more livable

Sincerely,

Charles Denney
Chairman



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Arlington County, Virginia

Neighborhood Traffic Calming Committee


Report on Arlington County s Neighborhood Traffic Calming Program Process Criteria and Measures

January 19, 2000

ARLINGTON COUNTY, VIRGINIA

NEIGHBORHOOD TRAFFIC CALMING



EXECUTIVE SUMMARY


On March 13, 1999, the Arlington County Board appointed a committee to develop policies and procedures for a program as set forth by the Ad Hoc Committee on Neighborhood Traffic Calming (NTC) in November of 1998. The document that follows reflects the work of this Neighborhood Traffic Calming Committee (NTCC). It is comprised of the following Chapters:
I. Mission Statement, Goals, Objectives, and Strategies
II. Problem-Solving Process:
* Identify Problem
* Define Scope of Problem
* Collect Data to Confirm Existence of Problem
* Community Discussion of Confirmed Problems and NTC Measures
* Development of Action Plan
* Assessment of Community Support for Action Plan
* Project Funding
* Project Implementation
* Follow-up Evaluation of NTC Project
* Program Review and Refinement
III. Traffic Calming Measures and Criteria
* Traffic Calming Toolbox

Appendices

i. NTC Process Flow Chart
ii. Project Ranking Guidelines
iii. NTCC Funding Schedule
iv. Citizen Appeals
v. 85th Percentile Speed

In general, the Committee based its work on the Final Report of the Ad Hoc Committee. We diverged, however, in our approach to solving problems. Whereas, the Ad Hoc Committee's report was oriented around specific traffic calming measures, the NTC Committee developed a "problem-oriented" procedure aimed at finding the most appropriate measures for each situation.

Our philosophy was to use standard measurements to determine the severity of traffic problems. This information would then suggest a range of traffic calming measures as well as the level of public involvement required to develop an action plan.

The community would be supported and assisted by the NTCC and the Planning Division of the Department of Public Works in their efforts to solve their documented traffic problems.

Finally, we built into the new process tools to evaluate the success of each project and the process in general. For each completed project, follow-up data will be collected to determine the effectiveness of the traffic calming measures installed. At periodic intervals, these data will be evaluated as well as other information provided by citizens affected by our work to identify any needed changes to the program, standard traffic measurements, criteria for each traffic calming measure, or the process in general.


TABLE OF CONTENTS


Chapter I: Mission Statement, Goals, Objectives, and Strategies

Chapter II: Problem Solving Process

Identify Problem

Define Scope of Problem

Collect Data to Confirm Existence of Problem

Community Discussion of Confirmed Problems and NTC Measures

Development of Action Plan

Assessment of Community Support for Action Man

Project Funding

Project Implementation

Follow-up Evaluation of NTC Project

Program Review and Refinement


Chapter III: Traffic Calming

Traffic Calming Toolbox


APPENDIX

Neighborhood Traffic Calming Process Flow

Project Ranking Guidelines

NTCC Funding Schedule

Citizen Appeals

85th Percentile Speed


CHAPTER I: ARLINGTON COUNTY
NEIGHBORHOOD TRAFFIC CALMING
COMMITTEE (NTCC)


MISSION:

Develop and oversee a program to support the County Board's vision of an "urban village" by reducing the impact of vehicular traffic and improving pedestrian and bicyclist safety within and around residential areas in Arlington County.


GOALS:

1. Change the culture of neighborhood street use from "cars first" to "people first."

2. Develop street design guidelines which will make speed limits and other traffic controls on residential minor and principal streets "self-enforcing."

3. Coordinate NTCC efforts with the Pedestrian, Bicyclist, and ADA advisory committees.

4. Establish effective, fair, and consistent policies for implementing traffic calming measures.

5. Ensure that neighborhood street use is consistent with Master Transportation Plan designations and zoning to the greatest extent possible.

6. Redirect through traffic to the arterial road network.

7. Foster collaboration and a shared sense of purpose between County residents and staff in addressing traffic problems.

8. Reduce the number of cases requiring County Board intervention.


OBJECTIVES:

Note: numbering as in original report.

9. Refine County policies governing the NTC program and application of traffic calming measures.

10. Develop the NTC Program.

11. Implement the NTC Program.

12. Evaluate and refine the NTC Program

13. Make final recommendations to the County Board.


STRATEGIES


1. Refine County Policies governing the NTC Program and application of traffic calming measures.

a) Establish maximum tolerable speed and volume standards for residential streets.

b) Develop a formula incorporating number of residences, traffic volume, speed to determine extent to which streets are out of compliance.

c) Establish requirements for community outreach for each traffic calming measure

d) Develop criteria for applying traffic calming measures to problem streets.

e) Develop priorities for scheduling traffic calming projects.

Severity of problem Scope
Order in which received
Budget considerations
Community Support

f) Review County policies and public statements

g) Issues:

Do Master Transportation Plan street classifications match actual use?

What is the County's objective for streets which are classified as neighborhood streets but carry through traffic?

How far should the County go to move through traffic to the arterial roads?

How do we balance the interests of residents and users?


2. DEVELOP THE NEIGHBORHOOD TRAFFIC CALMING PROGRAM

a) Identify and refine data collection tools, methods, and procedures, including:
Origin-destination surveys
Speed classifiers
Review of street characteristics
Review of street use
Comparison of expected vs. actual street use
Resident surveys before, during, and after traffic calming measure installation

b) Develop communications tools to support and increase the effectiveness of the program, including:

Resource manual for citizens explaining policies and procedures
Public information campaign
Web site
Surveys
Public Meetings
~ Consensus-building sessions

c) Design procedure for notifying interested parties

d) Define traffic calming elements which prioritize pedestrian, bicyclist, and wheelchair safety.

Street width
crossing distances
bicycle paths
street geometry ~ wheelchair ramps
pedestrian amenities (sidewalk and tree lawn width, islands, etc.)


3. IMPLEMENT THE NEIGHBORHOOD TRAFFIC CALMING PROGRAM

Analysis and Design:

a) Evaluate and prioritize new NTC project requests
b) Assign staff and NTCC Members to new projects
c) Perform community outreach to reach neighborhood consensus about problems
d) Identify traffic calming measures to address problems
e) Review and refine proposals with community
f) Identify issues requiring resolution by the NTCC or County Board.
g) Determine resource requirements
h) Prepare budget for new projects
i) Submit new project request to the NTCC for approval

Construction:
j) Prioritize existing (approved and funded) NTC projects
k) Develop work plan and schedule
1) Evaluate newly approved NTC projects
m) Obtain resources
n) Prioritize new NTC projects
o) Monitor construction


4. EVALUATE AND REFINE THE NEIGHBORHOOD TRAFFIC CALMING PROGRAM.

a) Collect follow-up data (speed, volume, pedestrian safety, resident satisfaction, etc.)
b) Analyze results of NTC projects
c) Recommend corrective program action
d) Research new traffic calming strategies (on-going)
e) Revise resource requirements
f) Revise work plan and schedule
g) Report periodically to the County Board


5. Make final recommendations to the county Board

a) Compile results of data collected on completed projects to show overall results of NTC program
b) Recommend policy changes
c) Identify policy issues needing Board resolution.


CHAPTER II: NEIGHBORHOOD TRAFFIC CALMING
PROBLEM-SOLVING PROCESS


OVERVIEW

Neighborhood traffic problems are addressed through several steps. First, residents' perceptions of problems and their goals must be defined. Second, the specific traffic problem needs to be defined and quantified. Third, if there is a discrepancy between perceptions and data, this difference must be evaluated. Forth, the most appropriate traffic calming measure(s) must be selected. Fifth, the affected residents must agree on the proposed traffic calming measures. And sixth, the project must be funded

The process described below represents a community-based, "problemoriented" approach to deciding what to do about neighborhood traffic problems. The emphasis is on selecting traffic calming measures which will address documented problems instead of allowing preconceived, unstudied proposals to drive the process.

Underlying this new process are standards and criteria which determine the existence and severity of traffic problems. These standards and criteria are based on those used in successful traffic calming programs in North America and Europe. The criteria used herein correspond to requirements for individual traffic calming measures. In other words, traffic problems severe enough to warrant action would qualify for one or more of the approved traffic calming measures available for use in Arlington County.

Regardless of the scope of the traffic situation, the problem-oriented process is the same. The difference is in how broad the community participation must be. For example, addressing a speeding problem on a single block of a street would not require the same level of public discourse as a problem affecting several streets within a neighborhood. The most difficult problems are those where road users and affected residents have conflicting but equally valid needs. Central to the new process is an acknowledgment that communities need outside support to identify and solve traffic problems while respecting the interests of all affected parties.


PROCESS STEPS

The Neighborhood Traffic Calming Committee oversees the problem-solving process. When requests for traffic calming come in, from whatever source, Staff determine what course of action to follow. In some cases, Staff may propose to implement one of several regularly budgeted traffic control measures not subject to the

Traffic calming measures included in neighborhood action plans should be appropriate for the problem(s) being solved, result from the community working group considering all relevant viewpoints and opinions and should meet with community approval.

If the affected community approves the action plan, then the plan becomes eligible for funding. Like the Neighborhood Conservation Advisory Committee (NCAC) funding process, NTC projects will be funded in six-month cycles. Funded projects will be scheduled for implementation. Unfunded projects will be referred back to staff who will send the requesters a letter informing them of their options.

After an NTC project has been implemented and in place for several months, Staff and the NTCC will conduct a follow-up evaluation to determine the success of the project in solving the identified problem. The results of this evaluation will determine whether the NTCC needs to revisit the problem. Additionally, the results will be used during periodic programmatic reviews of the standards and criteria which form the basis of this program and to assess the effectiveness of specific traffic calming measures.



1. IDENTIFY PROBLEM

a) EXTERNAL SOURCES

Requests for traffic controls can come from an individual citizen, groups of citizens, civic associations, businesses, developers, County staff, or the County Board. It is important for the requester to focus on the problem and not let a preconceived, unstudied solution drive the process

b) INTERNAL SOURCES

Staff can initiate the NTC process when seeking to correct situations which are brought to their attention. For these problems, staff should recommend corrections to the NTCC. The NTCC will determine the appropriate level of public participation.

Upon receipt of a request for NTCC assistance, Staff will forward a questionnaire to the requester to gather the following information:

• Name(s) of Requester(s), contact information, and length of time in residence
• Description of the problem
• Specific location(s) of traffic problem(s)
• Time of day when problem occurs
• Dates/times of accidents (reportable and non-reportable)
• When the problem started
• Possible causes of the problem? (opinion)
• Any perceived dangers to pedestrians, residents, property as a result of the problem (opinion)
• Results residents hope to achieve (i.e., reduced speed, lower traffic volume, fewer accidents, lower risks to pedestrians, etc.)
• Names, addresses, phone numbers of nearby residents who share the concerns

Staff will acknowledge the completed questionnaire in writing to those whose names were provided and to the civic association (if any) and the NCAC representative (if any). This communication will outline the next steps to be taken and provide a time frame for collecting data and assessing the problem.


2. DEFINE SCOPE OF PROBLEM

Using the completed questionnaire, staff will inspect the area and review other information such as road and land-use maps to identify technical issues and to clarify their understanding of the problem from the requester's perspective. Specifically, staff will:
Identify affected streets and intersections
Identify users of affected streets and intersections (stakeholders)
Identify traffic generators
Analyze street use with respect to street classification
Document any other factors which might contribute the problem

Once staff understands the scope of the problem in terms of geography and road use, its next step is to collect data which will determine whether the problem meets any of the thresholds set by the NTCC and approved by the County Board.

Depending on the type of problem to be analyzed, some or all of the following data will be collected :

(Footnote: Appendix should describe specifications for each data collection effort)

Traffic Counts
Speeding Studies (classifier, police radar, etc.)
Origin/Destination Studies
Resident Opinion Surveys
Field observations
Other, to be identified as needed

Staff will review the results of the data collected and compare with the established criteria for identifying traffic problems. They will also add the location to the County's NTC Problem Database for reference and NTC Program review.


a) PROBLEM NOT CONFIRMED BY DATA COLLECTION

If the data collected indicate that the situation does not meet the thresholds which define traffic problems, staff will send a report to the NTCC with the results of the data and recommend that no action be taken. The situation will be eligible for reevaluation after a two-year waiting period.

Staff will report back to the community that the problem did not warrant any specific action by the NTCC or staff. If this response is not satisfactory, the citizens may request that the NTCC put the issue on its agenda for a brief presentation by the proponents in a future meeting. Additionally, as part of the on-going programmatic review of the NTC and the appeals processes, all problems for which measures have not been implemented by NTCC may be reviewed at a later time to determine whether the NTC thresholds and criteria are too narrow or the process breaks down in certain areas.


b) DATA COLLECTION CONFIRMS PROBLEM

If the objective data confirm the existence of a problem (which may or may not be the same problem identified by the requester), staff will prepare a problem report including:

Date request for help received
Name(s) of requester(s) and contact information
Problem Inventory (specific locations, times or day, etc.)
Dates/times of accidents (reportable and non-reportable)
Traffic Data Analysis (details attached)
Causes of problems
Risks to pedestrians, residents, property as a result of the problem
Geographic scope and boundaries
Potential Solutions
Names, addresses, phone numbers of nearby residents who share the concerns
List of people willing to work with the NTCC to solve problems
Date and time for meeting to discuss potential solutions and community role (if applicable)

Staff will forward this problem report to the NTCC for information and to the original requester, the civic association (if any), and the NCAC representative (if any), and any other individuals who have made their interest known by letter or petition. The NTCC will assign a member to oversee the community outreach and consensus-building required to decide how best to address the problem.


3. COMMUNITY DISCUSSION OF PROBLEMS AND NTC MEASURES

The NTCC representative and staff will meet with the original requesters to discuss possible courses of action. The initial meeting will have the following purposes:

Educate citizens about the process
Review the collected data
Discuss applicable NTC measures and requirements for each
Review process for achieving consensus on NTC measures
Formation of a working group

At this early stage, the discussion will focus on the problems rather than the merits of specific traffic control measures. Participants should leave these sessions understanding:

The scope and nature of the problems in their community
The NTC process that will be followed
What they can realistically expect from traffic calming
The necessity for working within their community to build a consensus for NTC measures

Staff, the NTCC representative, and facilitator (if any) should leave the meeting with an understanding of:

What residents hope to achieve
Sources of potential conflict within the neighborhood
Any issues not previously identified
A sense of the extent of community support for the NTCC effort to solve the problem(s)


4. COMMUNITY DEVELOPMENT OF ACTION PLAN

The number of working group meetings will depend on the complexity of the problem or problems. For complex problems, the NTCC will allow the community a period of three months to form a working group of the affected residents and other interested parties. If no working group has formed, the NTCC will consider whether to grant an extension or conclude the project.

The working group will be requested to produce periodic status reports to the NTCC for longer-term projects. If it appears that a community cannot reach agreement on an action plan, the NTCC may recommend that the community effort be suspended.

The outcome of the community problem-solving process should be a proposed plan of action. This can be as simple as a single traffic calming measure or as complicated as a neighborhood-wide plan.


5 NTCC REVIEW

When the working group has developed an action plan, Staff, the NTCC representative, and the working group representative will present it to the NTCC for discussion and comments.


6. ASSESS COMMUNITY SUPPORT FOR TRAFFIC CALMING

Each proposed traffic calming measure within the action plan requires a certain level of community support to be eligible for funding and implementation. To assess community support, Staff will prepare the following materials to mail to the affected households:

Letter explaining the proposed action plan and announcing a community meeting
Maps and diagrams explaining what the proposed measures will look like and where each will be located.
Level of response and support required for NTCC approval of plan.
Postage-paid return card with the resident's name, address, required signature line, and a "yes" or "no" box to be checked, as well as space for comments.

If an insufficient number of households respond within four weeks, members of the community working group assigned to that particular project will follow-up with those neighbors who failed to return their cards.

Support of the civic association(s) and local PTA's is not required but is strongly encouraged.

If the response is sufficient but negative toward the proposal, the NTCC will recommend either that the problem be referred back to the community outreach phase or that it be closed out as irreconcilable. If the project is referred back to the community, the NTCC may recommend alternative approaches, more likely to meet with community acceptance.

In the case of projects failing to receive support and being closed out, the NTCC will determine a minimum waiting period - one to four years - before the problem or problems may be resubmitted for NTCC assistance." Footnote: See Appendix 4: Citizen Appeals for more information


7. PROJECT FUNDING

a) PRIORITY RANKING GUIDELINES

In order to avoid diverting traffic from one neighborhood street to another, the NTCC supports the analysis of traffic problems on a neighborhood-wide basis and the development of a comprehensive plan to calm traffic throughout a neighborhood. This is similar to the process undertaken during development of a Neighborhood Conservation Plan under the NC program.

However, when it comes time to provide funds for the implementation of specific traffic calming measures, the NTCC will evaluate projects on a street-by-street basis, through the use of a priority ranking system (see Appendix 1). The system is intended to provide the NTCC with an objective method for assessing the severity of the traffic calming issue the project is intended to address. Other things being equal, projects with more severe problems, as shown by higher point values, will be recommended for funding before projects with less severe problems, as shown by their lower point values.

Prior to full NTCC discussion, its rankings subcommittee, working with County staff, will assign points to each eligible project under the NTCC project priority ranking guidelines subject to review by the full NTCC.

The proposed ranking system gives equal stress to speeding and volume, and assigns points for every reported, traffic calming- related accident. Additional points are given to projects on streets used by bicyclists and transit riders, with facilities that generate substantial amounts of pedestrian traffic, and with conditions leading to increased hazards. Further preference is given to projects that demonstrate high levels of community support.


b) PROJECT FUNDING SESSIONS

NTCC will place all eligible projects on a list for consideration during twice yearly NTCC funding sessions (see Appendix 2). Eligible projects will be discussed at the NTCC meeting prior to each funding session, and NTCC members are expected to visit eligible sites prior to the funding session. The funding process will proceed in the following fashion:

1. For each project, in priority order as determined by the point system:

• County staff describes project;
• Supporters and opponents of project are provided the opportunity to speak for or against funding; and
• NTCC members discuss specific issues.

2. NTCC debates and recommends project funding Recommended projects funded through bond issues will be referred to the County Board for final approval; projects recommended for funding through operational accounts will be referred to the County Manager.

Projects not recommended for NTC funding, for whatever reason, may be eligible for other funding sources, such as the Neighborhood Conservation Program and will be referred back to the community to investigate other funding sources. They also may remain on the NTC eligible projects list for subsequent funding sessions.


8. PROJECT IMPLEMENTATION

Once a project has been approved and funded, Staff performs the following actions:

• Preliminary engineering to determine scope of work
• Perform site survey
• Develop detailed construction drawings
• Acquire rights of way and easements
• Schedule construction either by County Staff or contractor
• Notify affected residents of construction schedule
• Execute construction
• Install landscaping treatments
• Repair any damage to private property


9. EVALUATE THE EFFECTIVENESS OF THE NTC PROJECT

a) Staff Collects "After" Data

• Repeat Tests from Initial Data Collection
• Perform Other Tests as Needed
• Survey residents
• Track changes in traffic patterns

b) NTCC and Staff Prepare Evaluation Report

• Compare "Before" and "After" Data
• Analyze Results
• Identify Next Steps and/or Corrective Actions for Failures

c) Close Out Problem

• Prepare Item for inclusion in periodic County Board Report
• Remove Project from Schedule
• Communicate with Citizens on any remaining issues, problems, or concerns


10. PROGRAM REVIEW AND REFINEMENT

Periodically, the NTCC will review the approved standards and criteria to determine whether they are appropriate for current conditions. This analysis will consider all NTC requests which did not meet the thresholds as well as those which did. Additionally, citizens who feel that the NTC Process needs refinement may bring their issues to the table for discussion and consideration by the NTCC and the County Board liaison.

It is important that Arlington County citizens find the NTC process to be fair and the policies consistently applied. Additionally, because this is a new program, the NTCC will closely monitor the following areas for effectiveness:

• The criteria used to determine whether a problem exists and how severe it is;
• The criteria which must be met in order to qualify for a traffic calming measure;
• The funding priorities
• The process
• Budget requirements

The initial review will take place one year after the County Board approves the NTC Program.


CHAPTER III: TRAFFIC CALMING
MEASURES AND CRITERIA

Traffic calming involves implementing strategic measures to reduce vehicle speed, excessive traffic volume, cut-through traffic on residential streets, and other safety-related neighborhood traffic concerns. The following definitions, measures and criteria are established for the NTC process.


1. DEFINITIONS

A. Speeding

A speeding problem exists when the 85th percentile speed on the affected street/s is in excess of 5 mph over the posted speed limit for at least a period of 24 hours or another appropriate time period determined by Staff. In other words, more than 15 percent of the drivers on the street travel more than 5 mph over the posted speed limit. This problem may exist over the course of the entire day. Other speeding-related problems may exist, such as infrequent high speed vehicles. Efforts to address these speeding problems can also be undertaken.

B. Excessive Traffic Volume

Excessive traffic volume is a disproportionately high volume of traffic that seems to promote excessive speeds, unsafe driving behaviors, and diminished livability on a neighborhood street s. Defined on a case-by-case basis.

C. Excessive Cut-through Traffic An excessive cut-through problem exists when more than 30% of the traffic in any given hour during the day uses the street/streets as a through street. Cut through traffic is defined as traffic not originating in or destined to the immediate neighborhood.

D. Other Neighborhood Traffic-Related Issues

Other traffic-related issues include lack of convenient crosswalks, lack of sidewalks, hazards for bicyclists, excessive noise from vehicles/trucks, etc. Safety for pedestrians may be an issue near schools, elderly living centers, playgrounds and other pedestrian traffic generators.


2. TRAFFIC CALMING MEASURES

The following is a list of measures available for use in traffic calming: nubs, traffic circles, street narrowing, raised crosswalk, median (raised or flush), chicane, rumble strips, flat top speed humps (not bumps), street closure (full and half), turn/ access restrictions, diverters (diagonal and semi), gateway treatments. woonerf, raised crosswalk, and truck restrictions.

Some measures are available for implementation under authority of the County Manager and do not need to go through the full NTC process such as roadway markings, mid-block crosswalks, multi-way stop signs, $200 warning signs for speeding, placement of a speed display trailer, arterial direction signs, marking of bike lanes, changes in parking restrictions, vegetation trimming, additional speed limit signs or "Stop Ahead" signs, and education programs. Measures are further addressed in the table in section 4.

The following is a list of considerations when selecting a measure for traffic calming. The measure selected, in general, should be:

• the most effective available
• the least adverse in impact
• the simplest available
• the least costly possible
• a stand-alone or single measure or in combination with other(s)
• within the range of professional traffic management guidelines
• a contribution to the overall attractiveness of County streets


3. CRITERIA FOR SELECTING A TRAFFIC CALMING MEASURE

The following factors should be considered when selecting a traffic calming measure.

A. Community Support: Speeding solutions should be supported by 60% of the households of the affected street/s. Cut-through solutions should receive 60% support from the households in the affected area, where the area includes not just the affected street but other potential parallel cut through streets, and or the entire neighborhood area bounded by the arterials which are generating the cut-though traffic. Some specific examples: Traffic Circles should obtain 60% support from the households on the affected streets within one block of the circle. Nubs should obtain support from 60% of the households on the affected street within one block of the intersection. See table for additional specifics.

B. Traffic Volume: Streets with defined traffic problems, but lower volumes of traffic may receive lower priority, less restrictive measures, and/or less expensive measures.

C. Effectiveness: Can the measure solve the problem, based on past experience here and elsewhere.

D. Street Geometrics: Street width, intersection size, and topography may lead to the exclusion or selection of certain measures. For example an overly small intersection may not be sufficiently large to accommodate a traffic circle.

E.Community Preference: A community will not be forced to receive a measure it does not support, and must show significant support (60%) for the measures it does want.

F. Existence of transit route, major school bus route or Emergency Medical Service Route: Additional approval and evaluation may be needed depending on the measure desired.

G. Schools: The presence of schools near a location increases the need for controlled vehicular traffic. However, vehicle trips for pick-up and drop-off to a school located in the neighborhood is not considered cut- through traffic, and should not be counted as such in a DPW analysis of the traffic data.

H. Community/Organization Support: The views of the local civic association/s or local PTA/s will be considered.

I. Traffic Management Resources: The Manual on Uniform Traffic Control Devices and other relevant professional traffic management publications may provide guidance on the selection of measures.


4. TRAFFIC CALMING TOOLBOX TABLE

				                   Minimum
				                   Community 
                                   Support       Relative
  Used for	Measure     Criteria   Needed	     Cost	    Comments

1 Convenience,  Roadway	    MUTCD      none	     low
  safety	Markings*
  information					


2 Cut-through	Street	    Cut-	60% of	     high
  traffic	Closure	    through	households
			    traffic	in the
			    problem	designated
					area of 
					impact**

3 Cut-through	Diverters   Cut-	60% of	     high
  traffic		    through	households
			    traffic	in the
			    problem	designated
					area of 
					impact**

4 Cut-through	Half	    Cut-	60% of	     high
  traffic	Street	    through	households
		Closure	    traffic	in the
			    problem	designated
					area of 
					impact**


5 Cut-through	Turn &	    Cut-	60% of	     low	Cut-through
  traffic	Access	    through	households		problem at
		Restric-    traffic	in the			certain 
		 tions	    problem	designated		times of
					area of 		the day
					impact**


6 Cut-through	One-Way	    Cut-	60% of	     low
  traffic	Streets	    through	households
			    traffic	in the
			    problem	designated
					area of 
					impact**


7 Cut-through	Truck	    Requires	Approval     low
  traffic	Restric-    County	of Civic
		 tions	    Board	Assn.
			    Approval	
					


8 Cut-through	Woonerf	    To be	To be	     high
  traffic,		    determined	determined
  speeding		    

9 Inter-	Multi-	    See 	Approval     low	High 
  section	Way	    revised	of Civic		expectation
  safety,	Stop	    warrants	Assn.			on non-
  pedest.	Sign	    adopted 				compliance 
  safety		    by the 				if vpd is
			    County				not high
			    Board on
			    10/7/99 


10 Pedest.	Midblock    signifi-    60% of 	     low	
   safety	cross-      cant 	households
   		walk *	    concentra-  in the
			    tion of	designated
			    pedest.	area of
			    traffic	impact**
					

11 Speeding	Traffic	    -85th% > 	60% of	     high	Not for 3-way
		Circle	      30 mph.	households		or offset
			    -only with	within			intersections
			    consent of	one block
			    Fire Dept.	of circle
			    & Transit
			      assoc.
			    -major street
			    to have low
			    left turn
			    volume


12 Speeding	Narrow	    85th% >	60% of	     high	Usually done
		streets	      5 mph	households		where no curb
			    above the	in blocks		& gutter in
			    speed	to be
			    limit	narrowed
			    

13 Speeding	Slow  	    85th% > 	60% of	     high	May impact
		Points	     30 mph	households		on-street
					in block		parking
					to be
					installed

 
14 Speeding	Median	    85th% > 	60% of	     high	Affects
			     30 mph	households		driveway
					in the			access to
					designated		residences
					area of
					high impact


15 Speeding	Chicane	    To be 	To be	     high
			    determined	determined  


16 Speeding	$200 Fine   Used where  Approval     low
		Speed 	    chronic	of Civic
		Warning     excessive   Assn.
		Signs	    speeding	


17 Speeding	Median	    Where 	60% of	     low	May be
		Bollards    speed	households		used to
		(SPCCD)	    limit <	in block(s)		enhance
			    30 mph	where			pedest.
			    -85th% > 	installed	     	safety.
		      	      30 mph.				Messages
			    -not on 				on signs
			     roads w/				may
			     > 1 lane				change.
			     in each
			     direction	
			    -requires
			     painted
			     or raised
			     median.



18 Speeding	Flat-top    -85th% > 	60% of	   medium	Area
		Speed Hump    32 mph	households 		petitioned
 	     		    -only with	on street		may need to
			     consent of	to 			be adjusted
			     Fire Dept.	receive			based on
			     & Transit  humps			street
			     assoc.				network
			    -street
			     grades <
			     8%
			    

19 Warning	Rumble 	    -85th% >	60% of	    medium	May cause	
		Strips	      30mph	households		noise
					in block 		complaints.
					to be 			Dangerous
					installed 		for
medium	-Dangerous for						bicyclists.


20 Speeding	Speed	    any 	as	    none		
		Display     citizen	requested
		Trailer *   complaint	

						 
21 Speeding,	Gateway	    -85th% >	60% of	    high	-Affected
   cut-			      30 mph	households		area to be
					in affected		determined
					area			on a case
   								by case basis
								-May discourage 
								cut-through

22 Speeding,	Nubs	   -85th% >	60% of	    high	Also	
   Pedest.	(curb	     30 mph	households		pedestrian
   safety	extensions,		within			benefits
		chokers) 		one block	


23 Speeding,	Raised	   -85th% >     60% of	    medium	
   pedest.	Crosswalk    32 mph     households
   safety 		   -Only w/	on street
			    consent 	where
			    of Fire	installed
			    Dept &
			    Transit
			    Assoc.
			   -major ped 
 			    crossing
			    point


24 Traffic	Arterial   MUTCD	Approval     low
   Volume	Direction		of Civic
   Reduction	Signs			Assn.	


* Administrative measures can be implemented by staff without going through the NTC 
process

** Areas of impact for these measures are to be determined on a case-by-case basis

Notes:
All measures can be used on neighborhood minor and principal streets, but measures 
1,9,10,20,24 can also be used on arterials and 12,17,22 can be used on minor arterials

APPENDIX





Project Ranking Guidelines


Measures and Definitions

Speeding
Average daily percentage of vehicles traveling more than 5 mph over the speed limit, at the point on the project street with the highest average speed. Points: 0-30

Volume

Average daily traffic volume, at the point on the project street with the highest average volume, divided by 100. Points: 0-30

Accidents

Number of reported, correctable accidents on the project street in the last three years. Points: 5 each

Bike/Transit Routes

Street designated as Official or Unofficial Bicycle Route on the Arlington County Bikeways Map, or used as a regular transit route by Metro Bus. Points: 5 each

Pedestrian Generators

Public and private facilities on or near the project street, such as schools, parks, community houses, senior housing, etc., which generate a substantial amount of pedestrian traffic. Points: 5 each

Dangerous Conditions

Conditions on the project street which lead to increased hazards, such as the absence of a sidewalk on either side of the street or inadequate, uncorrectable site distance problems. Points: 5 each

Community Support

Support from civic association or local PTA; each ten percentage points above required 60% on qualifying petitions/cards. Points: 5 each


NTCC FUNDING SCHEDULE

Spring
February 15
Deadline for project qualification and consideration by citizens' association

March
Eligible projects discussed at NTCC meeting

April
Project funding session



Fall
August 15
Deadline for project qualification and consideration by citizens' association

September
Eligible projects discussed at NTCC meeting

October
Project funding session




Note: Neighborhood Conservation Advisory Committee funding sessions are held in June and December, thus giving applicants additional opportunities to obtain support for their projects.



CITIZEN APPEALS

One of the NTCC's stated goals is to establish effective, fair, and consistent policies for implementing traffic calming measures. To that end, the most severe traffic problems will receive the highest priority for funding and implementation. Underlying the NTC Program are standard measures which define the severity of traffic problems. Often residents perceive that a problem exists when in fact one does not. Many traffic problems are not severe enough to qualify for NTCC assistance. Standard data collection tools and procedures will ensure that all problems are assessed in a consistent manner.

For confirmed traffic problems, each NTC measure has certain criteria which must be met. What this means is that even when a traffic problem has been documented, there may not be enough support within the neighborhood for the proposed traffic calming measures.

NTC Projects for which all criteria have been met and are eligible for funding may not receive funding because of higher priority projects and limited funds.

There may be citizens who feel that their traffic situation has not received a fair hearing by the NTCC and wish to appeal on that basis.

During the first year of operation, the NTCC will study the application of the measures and criteria to determine whether they are too broadly or narrowly drawn. In other words, criteria should be narrow enough that not every street in Arlington would qualify for traffic calming, but broad enough that traffic calming measures will be installed where the greatest need exists.

Citizens whose traffic problems were not found to be severe enough to qualify for traffic calming may request a meeting with the NTCC to discuss the data collected and the criteria the data were measured against. For situations where a problem was documented but the community could not agree on what to do about it, the community may resubmit their request in one to four years at the NTCC's option depending on the scope and complexity of the problem to be addressed. Specifically, a problem which is narrow in scope and simple to address could be revisited in one year. On the other hand, a larger scale community effort which requires extensive staff and NTCC resources may not be reconsidered by the NTCC for at least four years. The NTCC will make the determination as to an appropriate waiting period on a case by case basis at regularly scheduled meetings.

In cases where a project was approved for funding but no NTC funds were available, the NTCC and Public Works Planning staff will inform residents of their options.

Finally, citizens are invited to participate in the periodic programmatic review meetings and share their thoughts about how the NTC program could be improved.


85TH PERCENTILE SPEED

Definition: "That speed below which 85 percent of all traffic units travel, and above which 15 percent travel."

Footnote: Traffic Engineering- Theory and Practice, Louis J. Pignotara

What is the 85'h percentile speed and why do we use it?

In general, it is an accepted principle that the majority of drivers on a roadway select safe and proper speeds based on roadway and traffic conditions. For determining a speeding problem on a specific roadway, the 85'h percentile speed is often used because it is usually seen as approximately the high end of the "normal� speeds traveled by motorists on a given roadway. To illustrate the 85th percentile speed statistic, the attached figure was prepared, which shows a bell curve that was created by arranging all of the recorded vehicle speeds from a study in order from the lowest to the highest. In general, the 85th percentile speed statistic is of particular interest because it is often located at about the upper end of the speed range which includes a good majority of the traffic which is considered to select "safe and proper speeds." (See figure.) Typically, recorded speeds along the bell curve above the 85th percentile speed tend to occur much less frequently than the speeds below it. This is usually because the highest speeds recorded in a study are often erroneous readings or can be the result of a few motorists who are very unperceptive of roadway conditions or irresponsible.

How does the 85th percentile speed relate to Speed Limits?

The generally accepted traffic engineering practice is that speed limits should be set at the nearest 5 mph increment to the 85" percentile speed. For instance, if the 85th percentile speed on a road is measured to be 27 mph, then the speed limit on the road would typically be set at 25 mph. However, other considerations such as accidents and real dangers not perceivable by drivers may indicate the need for a lower speed limit. Since speed limits are generally set using the 85'h percentile, it is expected that 15 percent of the vehicles will exceed the speed limit on a regular basis.

How does the 85th percentile speed relate to speeding problems?

Frequently, a County engineering study will show that the 85'h percentile speed exceeds the speed limit of 25 mph established by the State code. Currently, if the 85'h percentile speed falls within the range of 25-30, it is not considered a speeding problem in Arlington County since this is reasonably close to the speed limit on neighborhood streets. Once the 85th percentile speed exceeds 30 mph, however, it is considered a moderate speeding problem (30-35 mph) or an excessive speeding problem (over 35 mph).

Here is a graphic display of an 85th percentile example.








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This page was last revised on: December 27, 2003.