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City of Memphis Pedestrian Facility Design Toolkit

January 2015 PREPARED BY: Alta Planning + Design DRAFT

2 | Memphis Pedestrian Facility Design Toolkit

This facility design toolkit is intended to assist the City of Memphis in the selection and design of pedestrian facilities. The toolkit pulls together best practices by facility type from public agencies and municipalities, and institutional design guidance nationwide. Each facility type is covered within a single sheet relaying associated treatments, important design information, example photos, schematics (if applicable), and a summary of guidance from current or upcoming draft state or national design standards. Existing standards are referenced throughout and should be the first source of information when seeking to implement any of the treatments featured here. The following standards were referenced in the development of this toolkit.

Introduction

National GuidanceThe Federal Highway Administration’s 2009 Manual on Uniform Traffic Control Devices (MUTCD) defines the standards used by road managers nationwide to install and maintain traffic control devices on all public streets, highways, bikeways, and private roads open to public traffic. The MUTCD is the primary source for guidance on lane striping requirements, signal warrants, and recommended signage and pavement markings.

Pedestrian treatments not explicitly covered by the MUTCD are often subject to experiments, interpretations, and official rulings by the FHWA. The MUTCD Official Rulings1 is a resource that allows website visitors to obtain information about these supplementary materials. Copies of various documents (such as incoming request letters, response letters from the FHWA, progress reports, and final reports) are available on this website.1

The American Association of State Highway and Transportation Officials (AASHTO) 2004 Guide for the Planning, Design and Operation of Pedestrian Facilities provides guidance on dimensions, use, and layout of specific pedestrian facilities. The standards and guidelines presented by AASHTO provide basic information, such as minimum sidewalk widths, dimensions, and recommended signage and pavement markings.

The National Association of City Transportation Officials’ (NACTO) 2012 Urban Street Design Guide2 is the newest publication of nationally recognized urban design guidelines, and offers guidance on the current state of the practice in street design. The NACTO Urban Street Design Guide is based on current practices in the best pedestrian environments in the world. The intent of the guide is to offer substantive guidance for cities seeking to improve active transportation in places where competing demands for the use of the right of way present unique challenges.

Some NACTO treatments are not directly referenced in the current versions of the AASHTO Guide or the MUTCD, although many of the elements of these treatments are found within these documents. In all cases, engineering judgment is recommended to ensure that the application makes sense within the land use and roadway context, given the many complexities of urban streets.

Meeting the requirements of the Americans with Disabilities Act (ADA) is an important part of any pedestrian facility project. The United States Access Board’s proposed Public Rights-of-Way Accessibility Guidelines3 (PROWAG) and the 2010 ADA Standards for Accessible Design4 (2010 Standards) contain standards and guidance for the construction of accessible facilities. This includes requirements for sidewalk curb ramps, slope requirements, and pedestrian railings along stairs.

State and Local GuidanceThe Tennessee Department of Transportation (TDOT) has published a variety of additional resources for designing pedestrian facilities. These include the TDOT Roadway Design Guidelines, Traffic Design Manual, and Standard Drawings. Additionally, the Knoxville Regional Transportation Planning Organization’s Complete Streets Design Guidelines and draft City of Memphis Complete Streets Design Manual contain the latest local guidance on pedestrian streetscape design.

1 FHWA. MUTCD Official Rulings. FHWA. Http://mutcd.fhwa.dot.gov/orsearch.asp2 NACTO Urban Street Design Guide. Http://nacto.org/usdg/3 U.S. Access Board. Public Rights-Way_Accessibility Guidelines (PROWAG). http://www.access-board.gov/prowac/4 U.S. DOJ. Http://www.ada.gov/2010ADAstandards_index.htm

http://mutcd.fhwa.dot.gov/

http://mutcd.fhwa.dot.gov/orsearch.asp

http://nacto.org/cities-for-cycling/design-guide/

http://www.tdot.state.tn.us/chief_engineer/assistant_engineer_design/design/DesGuide.htm

http://www.tdot.state.tn.us/chief_engineer/assistant_engineer_design/design/Traffic_Design_Manual.pdf

http://www.tdot.state.tn.us/Chief_Engineer/engr_library/stddrlib.htm

http://www.tdot.state.tn.us/bikeped/CompleteStreets.pdf

Alta Planning + Design | 3

The facility design toolkit is organized into the following sections.

CrossingsCrossings are potential conflict points between pedestrians and vehicles and thus require design treatments that set clear expectations for all roadway users. This section includes design guidance for marked crosswalks in various roadway contexts, pedestrian-friendly intersection geometry, and pedestrian accommodation at signalized intersections. Contents include:

Crosswalks• Marked Crosswalks at Intersections

• Marked Crosswalks at Mid-block

• Crosswalk Marking Maintenance

Intersection Geometry• ADA Compliant Curb Ramps

• Advance Stop Lines

• Minimizing Curb Radii

• Curb Extensions

• Channelized Turn Lanes

Signalized Crossings• Pedestrians at Signalized Intersections

• Pedestrian Traffic Signal Enhancements

• Left Turn Signal Phasing

Enhanced CrossingsSeveral design treatments exist to enhance pedestrian crossings at locations where marked crosswalks alone are insufficient for the roadway and land use context. This section provides guidance on each enhanced treatment as well as a guide to treatment selection based on the roadway’s speed, lane configuration, and traffic volumes. Contents include:

• Raised Crosswalks

• Median Refuge Islands

• Rectangular Rapid Flash Beacons

• Pedestrian Hybrid Beacons

• Enhanced Crossing Treatment Selection

Linear ImprovementsSidewalks are the primary linear facility provided for pedestrians. Since state and local guidelines include detailed design guidance for sidewalks in the City of Memphis, this toolkit focuses on specific sidewalk challenges as well as opportunities other than sidewalk installation to improve pedestrian safety along corridors and between intersections. Contents include:

• Sidewalk Obstructions at Driveways

• Lane Reconfigurations and Road Diets

• Neighborhood Slow Zones

Speed and Volume Controls• Traffic Calming - Vertical Elements

• Traffic Calming - Horizontal Elements

• Traffic Calming - Diversion


Contents

Introduction ........................................................................................................................................... 2

Crossings

Marked Crosswalks at Intersections .................................................................................................. 5

Marked Crosswalks at Mid-block ....................................................................................................... 6

Crosswalk Marking Maintenance ....................................................................................................... 7

ADA Compliant Curb Ramps ............................................................................................................ 8

Advance Stop Lines .............................................................................................................................. 9

Minimizing Curb Radii ...................................................................................................................... 10

Curb Extensions ...................................................................................................................................11

Channelized Turn Lanes .................................................................................................................... 12

Pedestrians at Signalized Intersections ........................................................................................... 13

Pedestrian Traffic Signal Enhancements .........................................................................................14

Left Turn Signal Phasing ................................................................................................................... 15

Enhanced Crossings

Raised Crosswalks ................................................................................................................................16

Median Refuge Islands ........................................................................................................................17

Rectangular Rapid Flash Beacons (RRFB) .....................................................................................18

Pedestrian Hybrid Beacon ..................................................................................................................19

Enhanced Crossing Treatment Selection - Option 1 .................................................................... 20

Enhanced Crossing Treatment Selection - Option 2 .................................................................... 21

Linear Improvements

Sidewalk Obstructions and Driveways ............................................................................................ 22

Lane Reconfigurations and Road Diets .......................................................................................... 23

Neighborhood Slow Zones ............................................................................................................... 24

Traffic Calming - Vertical Elements ................................................................................................ 25

Traffic Calming - Horizontal Elements .......................................................................................... 26

Traffic Calming - Diversion ............................................................................................................. 27


Parallel markings are the most basic crosswalk marking type

Materials and Maintenance

Because the effectiveness of marked crossings depends entirely on their visibility, maintaining marked crossings should be a high priority. Thermoplastic markings offer increased durability over conventional paint. See Crosswalk Marking Maintenance for more guidance.

Discussion

Continental crosswalk markings should be used at crossings with high pedestrian use, particularly where the crossing is not controlled by signals or stop signs, such as a local street crossing of a multi-lane arterial. These type of markings should also be used where vulnerable pedestrians are expected, including crossings near schools.

Additional References and GuidelinesTDOT. Standard Drawings - Traffic Control Pavement Markings. 2011.FHWA. Manual on Uniform Traffic Control Devices. (3B.18). 2009. AASHTO. Guide for the Planning, Design, and Operation of Pedestrian Facilities. 2004. FHWA. Safety Effects of Marked vs. Unmarked Crosswalks at Uncontrolled Locations. 2005. FHWA. Crosswalk Marking Field Visibility Study. 2010.NACTO. Urban Street Design Guide. 2013.

Description

A marked crosswalk signals to motorists that they must stop for pedestrians and encourages pedestrians to cross at designated locations. Installing crosswalks alone will not necessarily make crossings safer, especially on multi-lane roadways.

Marked crosswalks across the uncontrolled leg of unsignalized intersections should follow the design guidance of marked crosswalks at mid-block locations. See Marked Crosswalks at Mid-Block for more guidance.

Guidance

At signalized intersections, all crosswalks should be marked. At unsignalized intersections, crosswalks may be marked under the following conditions:

• At an intersection within a school zone or on a walking route.

• At a complex intersection, to orient pedestrians in finding their way across.

• At an offset intersection, to show pedestrians the shortest route across traffic with the least exposure to vehicular traffic and traffic conflicts.

• At an intersection with visibility constraints, to position pedestrians where they can best be seen by oncoming traffic.Continental markings provide

additional visibility

Marked Crosswalks at Intersections

The crosswalk should be located to align as closely as possible with the through pedestrian zone of the sidewalk corridor


Detectable warning strips help visually impaired pedestrians identify the edge of the street

Crosswalk markings legally establish mid-block pedestrian crossing

W11-2, W16-7P

DescriptionAn effective pedestrian crossing at an uncontrolled location consists of a marked crossing area, warning signage, and other markings to slow or stop traffic. Designing crossings at mid-block locations depends on an evaluation of motor vehicle traffic vol-umes, line of sight, pedestrian traffic volumes, land use patterns, vehicle speed, and road type and width.

When space is available, a median refuge island may improve user safety by providing pedestrians space to cross one side of the street at a time. See Median Refuge Islands in the Enhanced Crossings section for more guidance.

GuidanceMarked crosswalks at mid-block locations should not be installed without additional crossing enhancements when the speed limit of the roadway is greater than 40 MPH and the roadways has either of the following volume and physical characteristics:

• 12,000 ADT or greater on four-lane roads without a raised median or pedestrian refuge island

• 15,000 ADT or greater on four-lane roads, with a raised median or pedestrian refuge island

See Enhanced Crossing Treatment Selection for more guidance on the need for crossing enhancements at mid-block crossings based on speed, lane, and traffic volume levels. Minimum sight distance:

• 25 MPH zone: 155 feet• 35 MPH zone: 250 feet• 45 MPH zone: 360 feet

Marked Crosswalks at Mid-block


Locate longitudinal markings out of wheel tread when possible to minimize wear and maintenance costs.

Discussion

Uncontrolled crossings of multi-lane roadways with over 15,000 ADT may be possible with features such as sufficient crossing gaps in vehicular traffic (more than 60 per hour), median refuges, or active warning devices like rectangular rapid flash beacons or in-pavement flashers, and good sight distance. For more information see the Enhanced Crossings section.

On roadways with low to moderate traffic volumes (<12,000 ADT), a raised crosswalk may be the most appropriate crossing design to improve pedestrian visibility and safety. For more information, see the Enhanced Crossings Section.

Additional References and GuidelinesAASHTO. Guide for the Development of Bicycle Facilities. 2012.

FHWA. Manual on Uniform Traffic Control Devices. 2009.

FHWA. Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled

Locations - Final Report and Recommended Guidelines. 2005.

Pavement marking distances not to scale. For illustration purposes only)

Advance stop lines should be placed 20-50 feet in advance of multi-lane uncontrolled mid-block crossings


Crosswalk Marking MaintenanceDescriptionMarked crosswalks are among the most fundamental pedestrian crossing treatments. Unfortunately, they are also subject to a high degree of wear and require periodic re-striping. A variety of materials are used with varying levels of durability and cost, including conventional and preformed thermoplastic, epoxies, tapes, and paint. Other material attributes to consider include retroreflectivity, color, surface friction, stability, pavement type, and materials used for existing markings.

Guidance• As described in Marked Crosswalks at Intersections, Continen-

tal or “Zebra” longitudinal markings are preferred over transverse markings in high-traffic pedestrian areas for their higher visibility and durability. Space the crosswalk bars of continental crosswalks, so that they are not in the vehicle tire path to reduce wear from vehicles.

• Monitor the durability of crosswalk markings at locations where there are high vehicle turning movements, particu-larly where there are large vehicles such as trucks or buses.

• Thermoplastics have been shown to have the highest durability but are also the most expensive striping material, requiring grinding and surface preparation before removal and replacement on concrete. Thermoplastic is typically replaced every 2-3 years.

• Paint is generally the least expensive, but may need to be reapplied several times a year.

• Roadway surface condition and maintenance of cracks and potholes in and around crosswalks must also be monitored and repaired when necessary.

• Establish a regular annual inspection and maintenance schedule, and provide several ways for the public to report maintenance needs.

DiscussionBecause thermoplastic crosswalk markings have a higher cost (and longer lifespan), many communities opt to invest in thermoplastic over paint as a part of larger construction or repaving project budgets. This strategy has helps to relieve tighter maintenance budgets by reducing the level of maintenance required by crosswalks using cheaper, less durable materials.

Additional References and GuidelinesFHWA. Guide for Maintaining Pedestrian Facilities for Enhanced Safety Research Report. 2013.

AASHTO. Guide for the Planning, Design, and Operation of Pedestrian Facilities. 2004

Monitor condition of crosswalks along large vehicle routes and high turning movement locations

Place crosswalk bars outside the vehicle tire path

Maintain roadway surface conditions so that they are free of cracks, potholes, and uneven surfaces


Materials and MaintenanceIt is critical that the interface between a curb ramp and the street be maintained adequately. Asphalt street sections can develop potholes at the foot of the ramp, which can catch the front wheels of a wheelchair.

Discussion

The edge of an ADA compliant curb ramp shall be marked with a tactile warning device (also known as truncated domes) to alert people with visual impairments to changes in the pedestrian environment. Contrast between the raised tactile device and the surrounding infrastructure is important so that the change is readily evident to partially sighted pedestrians. These devices are most effective when adjacent to smooth pavement so the difference is easily detected.

Additional References and GuidelinesUnited States Access Board. Accessibility Guidelines for Buildings and Facilities.

2002.

United States Access Board. Accessibility Guidelines for Pedestrian Facilities in the

Public Right of Way; Shared Use Paths. 2013.

USDOJ. ADA Standards for Accessible Design. 2010.

TDOT. Standard Drawings - Roadway and Pavement Appurtenances. 2013.

Description

Curb ramps are the design elements that allow all users to make the transition from the street to the sidewalk. A sidewalk without a curb ramp can be useless to someone in a wheelchair, forcing them back to a driveway and out into the street for access. There are a number of factors to be considered in the design and placement of curb ramps.

Although diagonal curb ramps might save money, they create potential safety and mobility problems for pedestrians, particularly those using wheelchairs and blind pedestrians. Diagonal ramps orient users into the traffic zone, and force wheelchairs to turn and re-enter the crosswalk. Blind pedestrians are oriented into the middle of the intersection, instead of directly into the crosswalk as with perpendicular ramps. Diagonal curb ramp configurations are not recommended.

Guidance

• The level landing at the top of a ramp shall be at least 4 feet long and at least the same width as the ramp itself.

• The ramp shall slope no more than 1:10, with a maximum cross slope of 2.0%. A slope of no more than 1:12 is desirable.

• If the ramp runs directly into a crosswalk, the landing at the bottom will be in the roadway.

• If the top landing is within the sidewalk or corner area where someone in a wheelchair may have to change direction, the landing must be a minimum of 5’-0” long (in the direction of the ramp run) and at least as wide as the ramp, although a width of 5’-0” is preferred.

Parallel Curb RampDiagonal Curb Ramp(Not recommended)

Perpendicular Curb Ramp

Curb ramps shall be located so that they do not project into vehicular traffic lanes, parking spaces, or parking access aisles. Three configurations are illustrated below.

Diagonal ramps shall include a clear space of at least 48” within the crosswalk for user maneuverability

ADA Compliant Curb Ramps

(Crosswalk spacing not to scale. For illustration purposes only)


May permit bicyclists to stop at the crosswalk rather than the advance stop bar.

R1-5c

Guidance

General

• Install advance stop lines prior to any marked crosswalk.

• Provide advance stop lines in each direction of motor vehicle travel.

Controlled Crossings

• Provide a minimum of 4’ between stop lines and the crosswalk at controlled intersections. A greater distance may be appropriate depending on the roadway and land use context, but the stop line should not be placed more than 30 feet from the nearest edge of the intersecting traveled way.

• Stop lines may be staggered logitudinally on a lane-by-lane basis to improve the driver’s view of pedestrians, provide better sight distance for turning vehicles, and increase the turning radius for left-turning vehicles.

Uncontrolled Crossings

• Provide a minimum of 40’ between stop lines and the nearest signal at signalized mid-block crossings.

• Provide between 20’-50’ between stop lines and the crosswalk at uncontrolled multi-lane crossings.

• A “Stop Here for Pedestrians” sign must accompany the advance stop bar on multi-lane approaches.

Description

Advance stop lines increase pedestrian comfort and safety by stopping motor vehicles in advance of marked crosswalks, allowing vehicle operators a better line of sight of pedestrians and giving inner lane motor vehicle traffic time to stop for pedestrians.


Because the effectiveness of markings depends entirely on their visibility, maintaining markings should be a high priority.

Discussion

If a bicycle lane is present, mark the advance stop line for the bicycle lane 4’ from the crosswalk and mark the stop line across the vehicular lanes an additional 5’ from the bicycle lane stop line.

Additional References and Guidelines


Advance Stop Lines

Wide stop lines used for increased visibility

Example of advance stop lines at an uncontrolled crossing



Improperly designed curb radii at corners may be subject to damage by large trucks.

Discussion

Several factors govern the choice of curb radius in any given location. These include the desired pedestrian area of the corner, traffic turning movements, street classifications, design vehicle turning radius, intersection geometry, and whether there is on-street parking or a bike lane (or both) between the travel lane and the curb.

Additional References and GuidelinesAASHTO. Guide for the Planning, Design, and Operation of Pedestrian Facilities.

2004.

AASHTO. A Policy on Geometric Design of Highways and Streets. 2004.

NACTO. Urban Street Design Guide. 2013.

Description

The size of a curb’s radius can have a significant impact on pedestrian comfort and safety. A smaller curb radius provides more pedestrian area at the corner, allows more flexibility in the placement of curb ramps, results in a shorter crossing distance, and requires vehicles to slow more on the intersection approach. During the design phase, the chosen radius should be the smallest possible for the circumstances.

Guidance

The curb radius may be as small as 3 ft where there are no turning movements, or 5 ft where there are turning movements and adequate street width. On-street parking and bike lanes create a larger effective turning radius and can therefore allow a smaller curb radius.

Curb Radius

Minimizing Curb Radii

Effective turningRadius



Planted curb extensions may be designed as a bioswale, a vegetated system for stormwater management.

Discussion

If there is no parking lane, adding curb extensions may be a problem for bicycle travel and truck or bus turning movements.

Additional References and GuidelinesAASHTO. Guide for the Planning, Design, and Operation of Pedestrian Facilities. 2004. AASHTO. A Policy on Geometric Design of Highways and Streets. 2004.NACTO. Urban Street Design Guide. 2013.City of Memphis and Shelby County. Stormwater Management Manual - Volumes 2 and 3. 2006.

Description

Curb extensions, also called curb bulbouts and neckdowns, minimize pedestrian exposure during crossing by shortening the crossing distance and giving pedestrians a better chance to see and be seen before beginning to cross. Curb extensions are appropriate for any crosswalk where it is desirable to shorten the crossing distance and there is a parking lane adjacent to the curb.

Guidance

• In most cases, curb extensions should be designed to transition between the extended curb and the running curb in the shortest practicable distance.

• For purposes of efficient street sweeping, the minimum radius for the reverse curves of the transition is 10 ft and the two radii should be balanced to be nearly equal.

• Curb extensions should terminate one foot short of the parking lane to maximize bicyclist safety when bicycle lanes are not present. This buffer is also preferred when bicycle lanes are present.

Crossing distance is shortened

Curb Extensions

Curb extension length can be adjusted to accommodate bus stops or street furniture.

1‘ buffer from edge of parking lane preferred

Running curb

Extended curb

Reverse curb radius

(Curb radii not to scale. For illustration purposes only)


Materials and Maintenance Signage and striping require routine maintenance.

DiscussionWhere signalization of the right-turn lane crossing is considered, use of push-button actuation or passive detection is recommended to reduce delay for motor vehicles when pedestrians are not present.

Unless the turning radii of large vehicles, such as tractor-trailers or buses must be accommodated, the pavement in the channelized right-turn lane should be no wider than 16 feet. Mark edge lines to restrict the painted width of the travel way of the channelized right-turn lane to 12 feet to slow smaller vehicles.

Additional References and Guidelines NCHRP. Web-Only Document 208: Design Guidance for Channelized Right-Turn

Lanes. 2011.

NACTO. Urban Streets Design Guide. 2013

ITE. Designing Walkable Urban Thoroughfares. 2010

Guidelines• Where possible, eliminate channelized right turn lanes to slow

turn speeds and increase rates of yielding to pedestrians. If channelized right turn lanes are already present, or if the design is unavoidable:• Design for slow speeds (5-10 mph) and high pedestrian

visibility (see diagram below).• Install standard pedestrian crossing assembly and R10-15

“Turning Vehicles Yield to Pedestrians” signage.• Mark with high-visibility crosswalks.• At channelized right turn lane locations with high pedestrian

volumes and high volumes of right-turning vehicles or docu-mented safety issues, consider pedestrian priority treatments such as raised crosswalks, real-time warning devices, or signalization of the right turn lane paired with a pedestrian signal head and a stop bar preceding the crosswalk.

• Raised concrete islands with “cut-through” paths are strongly preferred by pedestrians that use mobility aids or have vision impairments.

Locate crosswalk in the middle of the channelized turn lane, One car length back from the other street.

DescriptionChannelized right turn lanes are designed to increase vehicular capacity at intersections and reduce delay to drivers by allowing them to turn at higher speeds and avoid unnecessary stops. They are generally inappropriate in an urban context because they create conflicts with pedestrians and bicyclists and increase turning speeds.

The provision of a channelized right-turn lane is appropriate only on signalized approaches where right-turning volumes are high or large vehicles frequently turn and conflicting pedestrian volumes are low and are not expected to increase greatly.

Channelized Turn Lanes

Turn lane should be configured as an “add lane” to provide for deceleration and storage.

(Not to scale)W11-2, W16-7P


Pedestrians at Signalized Intersections

Materials and MaintenanceIt is important to repair or replace traffic control equipment before it fails. Consider semi-annual inspections of controller and signal equipment, intersection hardware, and detectors.

DiscussionWhen push buttons are used, they should be located so that someone in a wheelchair can reach the button from a level area of the sidewalk without deviating significantly from the natural line of travel into the crosswalk. Push button should be marked (for example, with arrows) so that it is clear which signal is affected.

In areas with very heavy pedestrian traffic, consider an all-pedestrian signal phase to give pedestrians free passage in the intersection when all motor vehicle traffic movements are stopped.

Additional References and GuidelinesUnited States Access Board. Proposed Accessibility Guidelines for Pedestrian

Facilities in the Public-Right-of-Way (PROWAG). 2011.

AASHTO. Guide for the Planning, Design, and Operation of Pedestrian Facilities.

2004.


DescriptionPedestrian Signal Heads

Pedestrian signal heads indicate to pedestrians when to cross at a signalized crosswalk. All traffic signals should be equipped with pedestrian signal indications except where pedestrian crossing is prohibited by signage.

Countdown pedestrian signals are particularly valuable for pedestrians, as they indicate whether a pedestrian has time to cross the street before the signal phase ends. Countdown signals should be used at all new and rehabbed signalized intersections.

Signal Timing and the Pedestrian Phase

Adequate pedestrian crossing time is a critical element of the walking environment at signalized intersections. The length of a signal phase with parallel pedestrian movements should provide sufficient time for a pedestrian to safely cross the adjacent street. The MUTCD recommends that traffic signal timing assumes a pedestrian walking speed of 4 ft per second at most. A speed of 3.5 ft per second is preferred.

At crossings where older pedestrians or pedestrians with disabili-ties are expected, crossing speeds as low as 3 ft per second should be assumed. Special pedestrian phases can be used to provide greater visibility or more crossing time for pedestrians at certain intersections (See Pedestrian Traffic Signal Enhancements).

Large pedestrian crossing distances can be broken up with median refuge islands. A pedestrian pushbutton can be provided on the median to create a two-stage pedestrian crossing. This ensures that pedestrians are not stranded on the median, and is especially applicable on large, multi-lane roadways with high vehicle volumes, where providing sufficient pedestrian crossing time for a single stage crossing may be an issue.

Audible pedestrian traffic signals provide crossing assistance to pedestrians with vision impairment at signalized intersections

Consider the use of a Leading Pedestrian Indication (LPI) to provide additional traffic protected crossing time to pedestrians. See Pedestrian Traffic Signal Enhancements for additional detail.


Pedestrian Traffic Signal EnhancementsDescriptionPedestrian-vehicle conflicts can occur when drivers perform-ing turning movements across the crosswalk do not see or yield to pedestrians who have the right-of-way. Pedestrians may also arrive at an intersection late, or may not have any indication of how much time they have to safely cross the intersection. Pedestrian traffic signal enhancements can be made to provide pedestrians with a head start, called a Leading Pedestrian Interval, or extend the walk time to allow them to safely and comfortably cross the street.

GuidanceLeading Pedestrian Intervals (LPI) are used to reduce right turn and permissive left turn vehicle and pedestrian conflicts. The through pedestrian interval is initiated first, in advance of the concurrent through/right/permissive left turn interval. The LPI minimizes vehicle-pedestrian conflicts because it gives pedestrians a 3-10 second headstart into the intersection, thereby making them more visible, and reducing crossing exposure time. Accessible Pedestrian Signals (APS) are recommended with an LPI.

Push buttons can be configured to provide additional crossing time when pedestrians arrive at the crossing during the flashing don’t walk interval. The MUTCD requires signage indicating the walk time extension at or adjacent to the push button (R10-32P).

Passive pedestrian detection devices save pedestrians the trouble of having to locate a push button. They are also capable of tracking pedestrians as they cross the intersection, and can be configured to extend the walk/flashing don’t walk interval when pedestrians are still in the intersection, and/or not dedicate walk time in the absence of pedestrians.

Materials and MaintenanceDetection and actuation equipment will require regular maintenance to ensure satisfactory actuation and pedestrian compliance. The City should make multiple ways available for the public to report malfunctioning equipment.

Discussion

When pedestrians have to wait an entire cycle for the next walk phase, a higher incidence of non-compliance, or jay-walking, or unpredictable behavior may occur. These signal enhancements facilitate safer, more predictable, and conspicuous crossing conditions. The Leading Pedestrian Interval and walk time extensions provide additional time for pedestrians who may need more time to cross the street such as wheel-chair users, people with disabilities, the elderly, and children.

Additional References and GuidelinesFHWA. Signal Timing Manual. 2008.FHWA. Signalized Intersections: Informational Guide. 2nd Edition. 2013.FHWA. Manual on Uniform Traffic Control Devices. 2009.NACTO. Urban Street Design Guide. 2013.

Passive Infrared Pedestrian Detector

Leading Pedestrian Interval

Pushbuttons will require regular maintenance and repair


Left Turn Signal PhasingDescriptionPedestrians are most vulnerable on the permissive left turn interval, where motorists trying to make a left turn are focused on the traffic signal head and potential gaps in on-coming traffic. They may not see pedestrians before they accelerate to clear the intersection, and may collide with pedestrians entering the crosswalk. Protected left turns and Protected-Permissive Left Turns (PPLT) are two phasing options that offer more protection for pedestrians.

Protected left turns eliminate the left turn conflict altogether and provide pedestrians with the most protection. The trade-off is often a longer signal cycle length and increased vehicle delay.

PPLT functions as a combination of the two phasing options, balancing the safety benefits of protected left turns and the efficiency benefits of permissive left turns. Motorists have left turn right-of-way with a protected green arrow, and a permissive left turn on a circular green display.

Guidelines

• PPLT should only be used with lead-lead left turn phasing.

• PPLT typically requires the use of a five-section signal display. A four-section signal display can be used if the circular green display and green arrow display end at the same time (when combined with circular displays) or if a flashing yellow arrow is used (when separate left turn signal head is used).

• The use of PPLT should not be considered at intersections where there are a high incidence of pedestrian collisions, poor visibility and sight lines, or unusual roadway geometries.


Detection and actuation equipment will require regular maintenance.

DiscussionSimilar to permissive-only left turn phasing, caution must be taken to avoid the “Yellow Trap” lead-lag scenario when motorists assume that traffic in the opposing direction is following a signal with identical and concurrent phasing. The “Dallas Signal” and flashing yellow arrow are two MUTCD approved displays that have been shown to effectively reduce incidence of yellow traps.

Additional References and GuidelinesTDOT. Traffic Design Manual. 2012.

FHWA. Signal Timing Manual. 2008.

FHWA. Signalized Intersections: Informational Guide. 2004.

FHWA. Manual on Uniform Traffic Control Devices. 2009


“Do Not Walk” Pedestrian signal intervals during Permissive Left Turn phase

5-Section signal display with concurrent protected left turn and through movements


No grade change with sidewalk level is preferred


Because the effectiveness of marked crossings depends entirely on their visibility, maintaining marked crossings should be a high priority. Ensure drainage pipes used to channel stormwater past the raised intersection are kept free of debris, to prevent stormwater from backing up and pooling.

Discussion

Like a speed hump, raised crosswalks have a traffic slowing effect which may be unsuitable on high-speed streets, designated transit or freight routes, and in locations that would reduce access for emergency responders. The noise of vehicles traveling over raised crosswalks may be of concern to nearby residents and businesses.

Additional References and GuidelinesFHWA. Manual on Uniform Traffic Control Devices. (3B.18). 2009.


2004.

USDOJ. ADA Standards for Accessible Design. 2010.


DescriptionA raised crosswalk or intersection can eliminate grade changes from the pedestrian path and give pedestrians greater prominence as they cross the street. Raised crosswalks should be used only in very limited cases where a special emphasis on pedestrians is desired; review on case-by-case basis.

Raised crosswalks are typically implemented on low-speed streets, Neighborhood Slow Zones and other areas of very high pedestrian activity. They are often paired with other treatments such as curb extensions for greater traffic calming effect.

Guidance• Use detectable warnings at the curb edges to alert vision-im-

paired pedestrians that they are entering the roadway.

• Approaches to the raised crosswalk may be designed to be similar to speed humps.

• Drainage improvements may be required depending on the grade of the roadway.

A tactile warning device should be used at the curb edge

Raised Crosswalks


Median Refuge IslandsGuidance• Refuge islands an be applied on any roadway with a left turn

center lane or median that is at least 6’ wide.• Islands are appropriate at signalized or unsignalized

crosswalks.• The refuge island must be accessible, preferably with an

at-grade passage through the island rather than ramps and landings.

• The island should be at least 6’ wide between travel lanes (to accommodate wheelchair users) and at least 20’ long (40’ minimum preferred).

• Provide double centerline marking, reflectors, and “KEEP RIGHT” signage in the island on streets with posted speeds above 25 mph.

Description

Median refuge islands are located at the mid-point of a marked crossing and help improve pedestrian safety by increasing pedestrian visibility and allowing pedestrians to cross one direction of traffic at a time.

Refuge islands minimize pedestrian exposure at mid-block crossings by shortening the crossing distance and increasing the number of available gaps for crossing.


Refuge islands may require frequent maintenance of road debris. Trees and plantings in a landscaped median must be maintained so as not to impair visibility, and should be no higher than 1 foot 6 inches.

Discussion

Median refuge islands can be installed on roadways with existing medians or on multi-lane roadways where adequate space exists (see Lane Reconfiguration and Road Diets in the Linear Improvements section). Median Refuge Islands should always be paired with crosswalks, and should include advance pedestrian warning signage when installed at uncontrolled crossings.

On multi-lane roadways, consider configuration with active warning beacons for improved yielding compliance.

Additional References and GuidelinesTDOT. Standard Drawings - Roadway and Pavement Appurtenances. 2011.TDOT. Traffic Design Manual. 2012.TDOT. Roadway Design Guidelines. 2014.Knoxville TPO. Complete Streets Design Guide. 2009. AASHTO. Guide for the Planning, Design, and Operation of Pedestrian Facilities. 2004.NACTO. Urban Street Design Guide. 2013.

Cut-through median refuge islands are preferred over curb ramps to better accommodate wheel chairs users.

W11-2, W16-7P


Guidance

Guidance for marked/unsignalized crossings applies.

• RRFBs shall not be used at crosswalks controlled by YIELD signs, STOP signs, or traffic control signals.

• RRFBs shall initiate operation based on user actuation and shall cease operation at a predetermined time after the user actuation or, with passive detection, after the user clears the crosswalk.


RRFBs should be regularly maintained to ensure that all lights and detection hardware are functional.

Discussion

Rectangular rapid flash beacons elicit the highest increase in compliance of all the warning beacon enhancement options.

A study of the effectiveness of going from a no-beacon arrangement to a two-beacon RRFB installation increased yielding from 18 percent to 81 percent. A four-beacon arrangement raised compliance to 88%. Additional studies of long term installations show little to no decrease in yielding behavior over time.

Additional References and GuidelinesNACTO. Urban Bikeway Design Guide. 2012.


FHWA. MUTCD - Interim Approval for Optional Use of Rectangular Rapid

Flashing Beacons (IA-11). 2008.

Description

Rectangular Rapid Flash Beacons (RRFB) are a type of active warning beacon used at unsignalized crossings. They are designed to increase motor vehicle yielding compliance on multi-lane or high-volume roadways.

RRFBs are typically activated by pedestrians manually with a push button, or can be actuated automatically with passive detection systems. See Enhanced Crossing Treatment Selection page for more details on appropriate applications.

Rectangular Rapid Flash Beacons (RRFB)

Providing secondary installations of RRFBs on median islands improves driver yielding behavior.

W11-2, W16-7P

Rectangular Rapid Flash Beacons (RRFB) dramatically increase compliance over conventional warning beacons.



GuidanceHybrid beacons may be installed without meeting traffic signal control warrants if roadway speed and volumes are excessive for comfortable pedestrian crossings.

• If installed within a signal system, signal engineers should evaluate the need for the hybrid signal to be coordinated with other signals.

• Parking and other sight obstructions should be prohibited for at least 100 feet in advance of and at least 20 feet beyond the marked crosswalk to provide adequate sight distance.

Materials and MaintenanceHybrid beacons are subject to the same maintenance needs and requirements as standard traffic signals. Signing and striping need to be maintained to help users understand any unfamiliar traffic control.

DiscussionHybrid beacon are normally activated by push buttons, but may also be triggered by infrared, microwave, or video detectors. The maximum delay for activation of the signal should be two minutes, with minimum crossing times determined by the width of the street.

Each crossing, regardless of traffic speed or volume, requires additional review by a registered engineer to identify sight lines, potential impacts on traffic progression, timing with adjacent signals, capacity, and safety.

The installation of HAWK beacons should also include public education and enforcement campaigns to ensure proper use and compliance.

Additional References and GuidelinesFHWA. Manual on Uniform Traffic Control Devices. 2009.

NACTO. Urban Bikeway Design Guide. 2012.

Description

Hybrid beacons or High-Intensity Activated Crosswalk (HAWK) beacons are used to improve non-motorized crossings of major streets. A hybrid beacon consists of a signal head with two red lenses over a single yellow lens on the major street, and a pedestrian signal head for the crosswalk.

HAWK beacons are only used at marked mid-block crossings or unsignalized intersections. They are typically activated with a pedestrian pushbutton at each end. If a median refuge island is used at the crossing, another pedestrian pushbutton can be located on the island to create a two-stage crossing. See Enhanced Crossing Treatment Selection page for more details on appropriate applications.

Pedestrian Hybrid Beacon

Pedestrian Hybrid Beacon

Should be installed at least 100 feet from side streets or driveways that are controlled by STOP or YIELD signs

W11-2



Enhanced Crossing Treatment Selection - Option 1Mid-block CrossingsMid-block crossings are an important street design element for pedestrians. They can provide a legal crossing at locations where pedestrians want to travel, and can be safer than crossings at intersections because traffic is only moving in two directions. Locations where mid-block crossings should be considered include:

• long blocks (longer than 600 ft) with destinations on both sides of the street;

• locations with heavy pedestrian traffic, such as schools and shopping centers; and

• at mid-block transit stops, where transit riders must cross the street on one leg of their journey.

Crossing Treatment SelectionThe specific type of treatment at a crossing may range from a simple marked crosswalk to full traffic signals or grade separated crossings. Crosswalk lines should not be used indiscriminately, and appropriate selection of crossing treatments should be evaluated in an engineering study before a marked crosswalk is installed. The engineering study should consider the number of lanes, the presence of a median, the distance from adjacent signalized intersections, the pedestrian volumes and delays, the average daily traffic (ADT), the posted or statutory speed limit or 85th-percentile speed, the geometry of the location, the possible consolidation of multiple crossing points, the availability of street lighting,and other appropriate factors.

FACILITY TYPE

PEDESTRIAN CROSSINGCONTEXTUAL GUIDANCE

LEGEND

At unsignalized locations

2 lane 3 lane 2 lane

2 lane with median refuge 3 lane 2 lane



6 lane with median refuge

Crosswalk Only (high visibility) EJ EJ X EJ EJ X X X X X X

Crosswalk with warning signage and yield lines EJ EJ EJ EJ X X X X X

Active Warning Beacon (RRFB) X EJ X X X X

Hybrid Beacon X X EJ EJ EJ EJ

Full Tra�c Signal X X EJ EJ EJ EJ EJ EJ

Grade separation X X EJ EJ EJ X EJ EJ EJ EJ EJ

Most Desirable Engineering Judgement EJ

Not Recommended X

Local Streets15-25 mph

Collector Streets25-30 mph

Arterial Streets30-45 mph

1

234

56


Enhanced Crossing Treatment Selection - Option 2

3 Lanes2-Way +

CTL

Lane Configuration(Assumes the pedestrian crossing volume is ≥ 20 pedestrians/hour)

5 Lanes2-Way +

CTL

7 Lanes2-Way +

CTL

4 Lanes2-Way, No MRI

2 LanesNo MRI

6 Lanes2-Way, No MRI

1,50

0 - 9

,000

ADT

> 9,

000

- 15,

000

ADT

> 15

,000

ADT

≤ 30 mph

35 mph

40 mph

≥ 45 mph

≤ 30 mph

35 mph

40 mph

≥ 45 mph

≤ 30 mph

35 mph

40 mph

≥ 45 mph

MC

RRFB

PHB

PHB

MRI + RRFB/PHB

PHB

PHB

PHB

PHB

MRIRRFB/PHB

PHB

PHB

Marked Crosswalks (MC) should be installed with advanced pedestrian warning signage (W11-2), and advance stop/yield lines. In-road ‘Yield

to Pedestrians signs may be also considered.

Median Refuge Islands (MRI) should be installed to shorten the pedestrian crossing distance and increase visibility of pedestrians. RRFBs may

also be considered at the median refuge island. This treatment is in addition to the installation of marked crosswalks and signage above.

Rectangular Rapid Flash Beacons (RRFB) should be installed on the side of roadway and in the median (if present). Consider Median

Refuge Island if possible. This treatment is in addition to the installation of marked crosswalks and signage above.

Pedestrian Hybrid Beacon (PHB) should be accompanied by pedestrian signals and detection. Consider a speed reduction before PHB. This

treatment is in addition to the installation of marked crosswalks and signage above.

MC

MC

MC

MC

PHB

PHB

MRI

MRI

MRI PHB

MRI

RRFB/PHB

MRI + PHB PHB MRI + PHB

PHB MRI + PHB PHB MRI + PHB

PHB MRI + PHB PHB MRI + PHB

PHB MRI + PHB

PHB

PHB

PHB

PHB

PHB

PHB

PHB

PHB

PHB

PHB

PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

MRI + RRFB/PHB

DescriptionThe contextual guidance presented here is intended to guide the selection of facilities, and does not preclude other appropriate treatments given location-specific conditions. It should not be used indiscriminately, and appropriate selection of crossing treatments should be evaluated in an engineering study before a marked crosswalk is installed. The engineering study should consider the number of lanes, the presence of a median, the distance from adjacent signalized intersections, the pedestrian volumes and delay, the average daily traffic (ADT), the posted or statutory speed limit or 85th-percentile speed, the geometry of the location, the possible consolidation of multiple crossing points, the availability of street lighting, and other appropriate factors. Raised crosswalks are to be implemented under limited conditions not detailed here. See Raised Crosswalks for more information on this specific treatment.


Sidewalk Obstructions and Driveways

Materials and MaintenanceSidewalks are typically constructed out of concrete and are separated from the roadway by a curb and gutter and sometimes a landscaped space. Surfaces must be firm, stable, and slip resistant.

DiscussionDriveways are a common sidewalk obstruction, especially for wheelchair users. When constraints only allow curb-tight sidewalks, dipping the entire sidewalk at the driveway approach keeps the cross-slope at a constant grade. However, this may be uncomfortable for pedestrians and could create drainage problems behind the sidewalk.

Additional References and GuidelinesUSDOJ. ADA Standards for Accessible Design. 2010.

United States Access Board. Proposed Accessibility Guidelines for Pedestrian

Facilities in the Public-Right-of-Way (PROWAG). 2011.


2004.

Description

Obstructions to pedestrian travel in the sidewalk corridor typically include driveway ramps, curb ramps, sign posts, utility and signal cabinets, pull boxes and poles, mailboxes, fire hydrants and street furniture.

Driveways and entrances to parking structures can also be particularly challenging due to the restricted visibility of exiting motorists.

Guidance• Reducing the number and width of access points reduces the

need for special provisions. This strategy should be pursued first.

• Obstructions such as utility boxes, pull boxes and traffic signal cabinetry should be placed in the furnishing or utility zone between the sidewalk and the roadway and set back from driveway entrances to increase visibility of pedestrians.

• The furnishing or utility zone also serves as the extended area where driveway grade changes should occur. This ensures a continuous cross slope along the pedestrian through zone.

Planter strips allow sidewalks to remain level, with the driveway grade change occurring within the planter strip.

Dipping the entire sidewalk at the driveway approaches keeps the cross-slope at a constant grade. This is the least-preferred driveway option.

When sidewalks abut angled on-street parking, wheel stops should be used to prevent vehicles from overhanging in the sidewalk.

Where constraints preclude a planter strip, wrapping the sidewalk around the driveway allows the sidewalk to still remain level.

When sidewalks abut hedges, fences, or buildings, an additional two feet of lateral clearance should be added to provide appropriate shy distance.


Lane Reconfigurations and Road Diets

BEFORE 11-12’ Travel 11’ Travel

AFTER

11’ Travel 11-12’ Travel

6’ Bike 10-12’ Travel 10-12’ Turn 6’ Bike10-12’ Travel

GuidanceVehicle lane width:

• Width depends on project. No narrowing may be needed if a lane is removed.

Bicycle lane width:• Standard bicycle lane width is 5-6 feet. A buffered bike

lane requires an additional 2-3 feet.

Number of Lanes:

• Generally, 3 lanes with a center turn lane can support 20,000 vehicles per day.

Materials and MaintenanceRepair rough or uneven pavement surface. Use bicycle compatible drainage grates. Raise or lower existing grates and utility covers so they are flush with the pavement.

DiscussionDepending on a street’s existing configuration, traffic operations, user needs, and safety concerns, various lane reconfigurations may be appropriate. For instance, a four-lane street (with two travel lanes in each direction) could be modified to provide one travel lane in each direction, a center turn lane, and bike lanes. Prior to implementing this measure, a traffic analysis should identify potential impacts. Road configurations are often paired with the road repaving schedule to reduce costs.


FHWA. Evaluation of Lane Reduction “Road Diet” Measures on Crashes.

Publication Number: FHWA-HRT-10-053. 2010.


DescriptionStreets with excess roadway capacity or wider lane widths often make excellent candidates for lane reconfigurations or road diet projects. The removal of a single travel lane will generally provide sufficient space for bike lanes on both sides of a street.

Even if the width of the sidewalk does not increase, pedestrians benefit from the buffer that the new bike lanes create between the sidewalk and travel lanes. Although the actual roadway crossing distance has not been reduced, the addition of bike lanes reduces the number of vehicle travel lanes pedestrians must cross.


Neighborhood Slow ZonesGuidance• Signs and pavement markings are the minimum treatments

necessary to designate a street as a Neighborhood Slow Zone.

• Neighborhood Slow Zones should have a maximum posted speed of 25 mph. Use traffic calming to maintain an 85th percentile speed below 22 mph.

• Implement traffic diversion based on the context of the street, using engineering judgment. Target motor vehicle volumes range from 1,000 to 3,000 vehicles per day.

• Intersection crossings should be designed to enhance safety and minimize delay for pedestrians and bicyclists.

Description

Neighborhood Slow Zones are low-volume, low-speed streets modified to enhance pedestrian and neighborhood safety and comfort by slowing and reducing vehicular traffic. Treatments include traffic calming, traffic diversion, intersection modifications, pedestrian lighting, signage, and pavement markings. Traffic calming treatments such as planted median islands and speed humps slow traffic. Traffic diverters actually reduce traffic by allowing through movements of pedestrians and bicyclists while discouraging or restricting similar through-trips by non-local motorized traffic.

Neighborhood Slow Zones are recommended on local roads in Memphis where speeds are low and right-of-way acquisition is necessary to install new sidewalks, making installation cost-prohibitive.

Materials and MaintenanceStormwater catchment basins with native plantings can be incorporated into curb extensions to reduce stormwater runoff and enhance neighborhood attractiveness.

Discussion

Neighborhood Slow Zone retrofits to local streets are often located on streets without existing signalized crossings of larger roadways. These include neighborhood streets and shared streets where travel by foot is prioritized over travel by automobile. Traffic diverters and pedestrian hybrid beacons are other potential treatments at major street crossings.

Traffic calming can deter motorists from driving on these streets and can be implemented on a trial basis. Anticipate and monitor vehicle volumes on adjacent streets to determine whether traffic calming results in an inappropriate increase in traffic volumes elsewhere.

Additional References and GuidelinesKnoxville TPO. Complete Streets Design Guide. 2009. NACTO. Urban Street Design Guide. 2013. IBPI. Bicycle Boulevard Planning and Design Handbook. 2009.Ewing, Reid. Traffic Calming: State of the Practice. 1999.Ewing, Reid and Brown, Steven. U.S. Traffic Calming Manual. 2009.

Speed humps

Curb extension

TrafficCircle


Traffic Calming - Vertical Elements

Materials and MaintenanceTraffic calming should be designed to minimize impacts to streets-weepers. Vegetation should be regularly trimmed to maintain visibility and attractiveness.

DiscussionEmergency vehicle response times should be considered where vertical deflection is used. Because emergency vehicles have a wider wheel base than passenger cars, speed lumps/cushions allow them to pass unimpeded while slowing most other traffic. Alternatively, speed tables are recommended because they cannot be straddled by a truck, decreasing the risk of bottoming out. Traffic calming can also deter motorists from driving on a street. Monitor vehicle volumes on adjacent streets to determine whether traffic calming results in inappropri-ate volumes elsewhere. Traffic calming can be implemented on a trial basis.


BikeSafe. Bicycle countermeasure selection system.

Ewing, Reid. Traffic Calming: State of the Practice. 1999.

Ewing, Reid and Brown, Steven. U.S. Traffic Calming Manual. 2009.


Description

Motor vehicle speeds affect the frequency at which automobiles pass pedestrians as well as the severity of crashes that can occur. Slower motor vehicle speeds greatly improve pedestrians’ comfort on a street. Slower vehicular speeds also improve motorists’ ability to see and react to pedestrians and minimize conflicts at driveways and other turning locations.

Vertical speed control measures are composed of slight rises in the pavement, on which motorists and bicyclists must reduce speed to cross.

Guidance• Speed humps are raised areas usually placed in a series

across both travel lanes. A 14’ long hump reduces impacts to emergency vehicles. Speed humps can also be offset to accommodate emergency vehicles.

• Speed humps can be challenging for bicyclists; gaps can be provided in the center or by the curb for bicyclists and to improve drainage.

• Speed lumps or cushions have gaps to accommodate the wheel tracks of emergency vehicles.

• Speed tables are longer than speed humps and flat-topped. Raised crosswalks are speed tables that are marked and signed for a pedestrian crossing.

• For all vertical traffic calming, slopes should not exceed 1:10 or be less steep than 1:25. Tapers should be no greater than 1:6 to reduce the risk of bicyclists losing their balance. The vertical lip should be no more than a 1/4” high.

Speed Hump

Offset Speed Hump

Temporary Speed Cushion

Raised Crosswalk


Traffic Calming - Horizontal Elements

Materials and MaintenanceTraffic calming should be designed to minimize impacts to streets-weepers. Vegetation should be regularly trimmed to maintain visibility and attractiveness.

DiscussionTraffic calming should allow smooth transitions for pedestrian at crossings and offer enhanced visibility. Horizontal traffic calming can be used to shorten pedestrian crossing distances. Horizontal speed control measures should not infringe on bicycle space.

Allowing a small space between islands/extensions and the curb can improve drainage flow and reduce construction and maintenance costs. Monitor vehicle volumes on adjacent streets to determine whether traffic calming results in inappropriate volumes elsewhere. Traffic calming can be implemented on a trial basis.

Additional References and GuidelinesAASHTO. Guide for the Development of Bicycle Facilities. 2012.BikeSafe. Bicycle countermeasure selection system. Ewing, Reid. Traffic Calming: State of the Practice. 1999.Ewing, Reid and Brown, Steven. U.S. Traffic Calming Manual. 2009.


DescriptionHorizontal traffic calming devices benefit pedestrians by causing drivers to reduce speeds. Speeds are reduced by constricting the roadway space or by requiring careful maneuvering around a roadway feature.

Traffic calming design elements reinforce the expectation of lowered speeds, and can help to define low-speed routes or areas that serve high numbers of pedestrians.

Horizontal traffic calming also provides opportunities for planting trees, vegetation, and stormwater management devices.

Guidance• Maintain a minimum clear width of 20 feet (or 28 feet with

parking on both sides), with a constricted length of at least 20 feet in the direction of travel.

• Chicanes are a series of raised or delineated curb exten-sions, edge islands, or parking bays on alternating sides of a street forming an “S”-shaped curb, which reduce vehicle speeds by requiring motorists to shift laterally through narrowed travel lanes.

• Pinchpoints are curb extensions placed on both sides of the street, narrowing the travel lane and encouraging all road users to slow down. When placed at intersections, pinchpoints are known as chokers or neckdowns. They reduce curb radii and further lower motor vehicle speeds.

• Traffic circles are raised or delineated islands placed at intersections that reduce vehicle speeds by narrowing turning radii and the travel lane. Traffic circles can also include a paved apron to accommodate the turning radii of larger vehicles like fire trucks or school buses.

Temporary Curb Extension

Chicane

Choker or Neckdown

Pinchpoint with Bicycle Access


Traffic Calming - Diversion

Materials and MaintenanceDepending on the diverter type, these treatments can be chal-lenging to keep clear of debris. Vegetation should be regularly trimmed to maintain visibility and attractiveness.

DiscussionA neighborhood education campaign should be conducted to inform nearby residents of the traffic changes, alleviate local access concerns, and build community support for the reduced traffic volumes and speeds along the Neighborhood Slow Zone.


Ewing, Reid. Traffic Calming: State of the Practice. 1999.

Ewing, Reid and Brown, Steven. U.S. Traffic Calming Manual. 2009.

Oregon Department of Transportation. Right-In Right-Out Channelization.

1998.

DescriptionTraffic diversion is a volume control measure used to reduce motor vehicle travel along routes designated for pedestrians and bicyclists by completely or partially restricting through traffic. Diversion is a strategy well-suited on Neighborhood Slow Zones. Higher vehicle volumes reduce pedestrian comfort and can result in more conflicts.

Implement volume control treatments based on the context of the Neighborhood Slow Zone using engineering judgment. Target motor vehicle volumes range from 1,000 to 3,000 vehicles per day.

Guidance• Partial closures allow full pedestrian and bicycle passage

while restricting vehicle access to one way traffic at that point.

• Diagonal diverters require all motor vehicle traffic to turn.

Median diverters restrict through motor vehicle movements while providing a refuge for pedestrians and bicyclists to cross in two stages.

• Street closures create a “T” that blocks motor vehicles from continuing on a neighborhood greenway, while pedestrian and bicycle travel can continue unimpeded. Full closures can accommodate emergency vehicles with the use of mountable curbs (maximum of six inches high).

Partial Closure

Diagonal Diverter

Median Diverter

Full Closure

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