traffic management

“If you design communities for automobiles, you getmore automobiles. If you design them for people, youget walk able, livable communities.” ~ Parris Glendening

MAHAVEER KUMAR JAINMADHUSUDAN RAMANMOUNICA REDDYMEGHNA V RAVOORMADHUPRIYA HARSHITHA N R

CHOREOGRAPHING TRAFFIC JUNCTIONS

ROUNDABOUT:ROUNDABOUT DESIGN INVOLVES TRADE-OFFS AMONG SAFETY, OPERATIONS, AND ACCOMMODATING LARGE VEHICLES.

FACTORS INFLUENCING THE DESIGN ROUNDABOUT:-Urban or Rural context.-Single lane or Double lane road.-Width of the Inscribed circle, Central island and Splitter island.-Width of the Entry, Exit and the Circulatory path.-No. of years it is planned for (future planning).-The largest vehicle that will pass through the junction.

Exit radius Entry radius

Circulatory path radius

Right turnpath radius

left turnpath radius

R3 < R2 < R1Ideal

The entry path radius shouldnot be significantly larger thanthe circulatory radius.The radius of the conflicting left-turn movement, R4 , must be

evaluated in order to ensure that the maximum speed differential between entering and circulating traffic is no more than 20 km/h (12 mph).

Inscribed

Circle Dia.

Entry radius

Central island

Circulatory road width

Exit radius

Yield line Splitter island

Apron

Entry width

Approach width

Departure width

Exit width

Non-motorised and vehicular roundabout

Vehicular

Cyclists

Pedestrian

Apron

ALIGNMENT OF APPROACHES AND ENTRIES :

PREFFERED ACCEPTIBLEUN-ACCEPTIBLE

Additional lane length Taper length

ENTRY WIDTH:

Entry width is the largest determinant of a roundabouts capacity. Entry widths should be kept to a minimum to maximize safety while achieving capacity and performance objectives.

When the capacity requirements can only be met by increasing the entry width,this can be done in two ways:1. By adding a full lane upstream of the roundabout and maintaining parallellanes through the entry geometry; or2. By widening the approach gradually (flaring) through the entry geometry. Flare lengths should be at least 25 m in urban areas and 40 m in rural areas.

Approach widening by adding full lane:

CIRCULATORY WIDTH:

The capacity of a round about can be increased in two ways :

Truck aprons generally provide a lower level of operations, but may be needed to provide adequate deflection while still accommodating the design vehicle.

Two-phase designs allow for small initial entry widths that can be easily expanded in the future when needed to accommodate greater traffic volumes.

1 to 4 m apronAnd different material

Use of apron

Point perpendicular to junction of inner entry curve and circulatory roadway

Flare length Start of flare

Flaring

ENTRY AND THE EXIT CURVES RADIUS :

EXIT CURVES AT SINGLE-LANE ROUNDABOUTS

SPLITTER ISLAND:

Larger splitter islands enhance safety, but require that the inscribed circle diameter be Increased.

-The pedestrian refuge should be a minimum width of 1.8 m.-At single-lane roundabouts, the pedestrian crossing should be located one vehicle-length (7.5 m [25 ft]) away from the yield line.-Ramps should be provided on each end of the crosswalk to connect the crosswalk to other crosswalks around the roundabout and to the sidewalk network.

Entry radii at urban single-lane roundabouts typically range from 10 to 30 m

EXIT CURVES AT SINGLE-LANE ROUNDABOUTS

Exit curves usually have larger radii than entry curves to minimize the likelihood ofcongestion at the exits.Generally, exit radii should be no less than 15 m

exit

exitExit

Inner entry curve

outer entry curve

Entry width

STOPPING SIGHT DISTANCE:

Stopping sight distance is the distance along a roadway required for a driver toperceive and react to an object in the roadway and to brake to a complete stopbefore reaching that object. Stopping sight distance should be provided at everypoint within a roundabout and on each entering and exiting approach.

At least three critical types oflocations should be checked forstopping sight distance.

Stopping sight distance

Stopping sight distance

Approach sightdistance.

Distance relating to stopping sight distance and circulatory speed.

2.0m(6ft)

Sight distanceon circulatory roadway.

15m

d1

d2

d1 entering stream distanced2 circulating stream distance

RIGHT-TURN BYPASS LANES:

Right-turn bypass lanes can be used in locations with minimalpedestrian and bicycle activity to improve capacity when heavyright-turning traffic exists.

Configurationof right-turn bypass lane withacceleration lane.

Configuration ofright-turn bypass with yield atexit leg.

By-pass lane

Abu Dhabi 2030 transport framework

Land use framework

Key design principles

• The best transport plan is a good land use plan.• Good street design starts with pedestrians.• A well designed street network provides safety for• all modes of transport.• Street connectivity enhances capacity and allows• smooth traffic flow.

ABU DHABI URBAN STREET DESIGN

In order to provide a high quality urban streetenvironment two basic influencing factors need to be considered and balanced. These factors are:• Land use context• Transport capacity

Khaleej Al Arabi Land Use Context

As the street progresses, it changes in nature and performs different functions for all the existing modes of transport - pedestrians, bicyclists, and motor vehicles - in the different urban settings.

Street typology examples

potential combinations of standard street types

• Modern European concepts of “shared” roadway• space, are not included, except on very low• volume, low speed streets.• Emphasis on the use of signalized junctions and

pedestrian crossings in order to maximize safety.• Shift in focus from a vehicle-dependent society to

adopt an integrated multi-modal transport system.

Streets in the Emirate will be responsive to their unique culture and environment.

Cultural inspiration

Hospitality

Family

Diverse population

geography

Climate

URBAN STREET DESIGN

User group priorities governing the design of all urban streets

PEDESTRIANS

TRANSIT RIDERS

BICYCLISTS

MOTOR VEHICLE RIDERS

Streets safe for children

Reduced speeds for increased safety.

• Safety and accessibility for all users

• Interconnected networks for all modes of transport

• Legibility and efficiency• Speed management• Environmental conditions• Consideration of landmarks,

views, vistas, and gateways

Considerations for Street Design

Inclusion of street elements including tram stops, bus stops, taxi lay-bys, in the street design without over-sizing the street right-of-way.The user interactionand conflict areas :• Main junctions (all users)• Transit stop and bicycle parking areas (pedestrianand bicycle)• Street crossings (pedestrian, transit, bicycle, and vehicle)

Avenue with transit meridian Boulevard with frontage lane

Prioritization of street design elements

PEDESTRIAN REALM ZONES

Clear sight lines between pedestrians, bicyclists, and motorists should be maintained in these areas.

• Frontage zone: Space for door openings, steps, utilities, people standing in the shadow of buildings

• Through zone: Obstacle-free space for pedestrian movement with a firm, smooth , slip-resistant surface.

• Furnishing zone: Primary buffer space between the active pedestrian walking area and adjacent thoroughfares; street furniture, landscaping, transit stops, kiosks

• Cycle track: Designated track may not be required in some places.

• Edge zone: Interface between the on-street parking or travel lane; waiting area for buses, taxis, traffic signs, signals.

One-way street Shared street Shared access lane

Transit Avenue with Side-Running Tram

Transit Avenue with Center-Running Tram

DESIGNING FOR PEDESTRIANS

Mid-block crossings: Locate them based on pedestrian movement, building entrances, attractions, etc. Include overhead signage and lights, provide curb extensions where there is on-street parking, raised crossings where traffic calming is necessary.

Pedestrian crossing locations

at all traffic-controlled junction legs

along desire lines (align with entrances to buildings, parks, walkways, etc.)

Should minimize conflicts withturning traffic, if U-turns are included

Maximum uninterrupted crossing distance shall not exceed 13.1 m.

Signalized crossings: Use of fixed-time (no push buttons) Prioritize pedestrians over vehicles or provide exclusive phase, dynamic timing (countdown) signals, audible pedestrian signals. Pedestrian Refuges: Minimum width of 2m, extend median

tips/noses past crossings at junctions , crossing area to be flush Crossing may be off-set or angled to orient pedestrians to oncoming traffic.

Raised crosswalk aligned with pathway

Consists of five mini roundabouts arranged around a sixth central roundabout. The complex junction offers multiple paths between feeder roads.

The roundabout was constructed according to the design of Frank Blackmore. Traffic flow around the larger, inner roundabout is anticlockwise (more proficient users), and traffic flows in the usual clockwise manner around the five mini-roundabouts and the outer loop(Less proficient users )

THE MAGIC ROUNDABOUT,SWINDON,ENGLAND

DESIGNING FOR PEDESTRIANS

Aligning Ramps and Crossings

Curb ramps: provide accessibility at street junctions, crossing for wheelchair users, strollers, bicyclists, etc.; should not be provided at channelization islands or median refuge islands. Provide good drainage at intersection corners.

Curb height: discourage motor vehicles from encroaching onto the pedestrian realm while still making it easy for pedestrians to step up and down from the pedestrian realm to the traveled way. Typical preferred height is 150mm.

Located in the center of the crosswalk

The low end of the curb ramp should meet the street grade with a smooth transition.

A maximum 1:50 cross slope on all paved surfaces in the pedestrian realm and street crossings

Driveway designed as a curb cut, not a minor junction

Refuge island for pedestrian crossing

Curb ramp

DESIGNING FOR TRANSIT USERS

BUSTOP DESIGN:• Bus-only lanes• Priority at signals• Should offer clear paved pedestrian access, shade

seating and route information• amenities include trash receptacle, bicycle parking,

lighting, real-time information display for bus arrivals.

Curbside bus stop length:• Near-side: 28 m • Far-side: 25 m

DESIGNING FOR BICYCLISTS

Bicycle lanes:• Highlight bicycle facilities with colored pavement• bicyclists are to yield to pedestrians at all intersection points• Bicycle lane of 1.5 – 2.5 m

Typical Cycle Track

Shared Waiting Space for Bicyclists andPedestrians at Junction

Bicycle parking:• Locate parking in

furnishing zone• Shaded, well-lit and

secured• Provide directional

signage

DESIGNING FOR MOTOR VEHICLES

Signalized U-turns with Crosswalk on Transit Boulevard

Lane transitions shall be minimized on urban streetsDo not use lane transitions within junctions.

U-turns enhance motor vehicle traffic flow, facilitateaccess management, and reduce left turn pressureat junctions.

Access management: Limit the size, quantity, and frequency ofdriveways to reduce conflict points in the pedestrian realm

Frontage Lanes: They are required when there is a parking demand on Boulevards or avenues.as narrow as possible in order to ensure slow travel speeds.offer a high quality bicycle facility

Typical Entry to Frontage Lane

Left Turn at Median

Medians, the dividing part of the traveled way, aretypically used to separate traffic flows and controlturning movements. They are typically located inthe middle of the street, but may be located on thesides (side medians) where there are frontage lanes.

Junction types

• Junctions are intersections of streets where through moving and turning pedestrians, bicyclists, transit vehicles, and motor vehicles all share the space.

• Minimize pedestrian exposure to moving vehicles by reducing crossing distance and the duration of the crossing.

• Design junctions with the understanding that turning vehicles may turn into any lane of the receiving street and larger vehicles may cross the centerline.

If junctions are too close to each other- insufficient queuing space.If junctions are too far away from each other -insufficient connectivity within the overall street network.

TRAFFIC JUNCTIONS

Curb Extension Increases Visibility

Sight Distance Requirements

Corners Designed for Trucks Allow High Car Speeds

Signalized junctions will have lower sight distance requirements.

maximum corner radius of 5 m shall be used for urban junctions

RIGHT-TURN LANES AT INTERSECTIONS

ROUNDABOUTS

Roundabouts shall be designed so that drivers yield to pedestrians and bicyclists.

A Complete Street is designed for all ages, abilities, and modes of travel. On Complete Streets, safe and comfortable access for pedestrians, bicycles, transit users and people with disabilities is provided.

• A complete street includes: sidewalks,

• bike lanes (or wide paved shoulders),

• special bus lanes, • comfortable and accessible public

transportation stops,• frequent and safe crossing

opportunities, • median islands, • accessible pedestrian signals, • curb extensions, • narrower travel lanes, • roundabouts, • street furniture, • wide pedestrian rights-of-way • trees

COMPLETE STREETS

Median,access way, bike lanes, plant strip,sidewalks. Pedestrian crossing given importance Signals rpovided at junction.

Bike lane differentiated by colour between accessway and parking.

Typical Raised junction

Typical Raised Crossing

Typical Lateral Shift Typical Choker

Typical Chicane Typical Center Island Narrowing

Audio Tactile Paving ATP (also known as Rumble Strips) is a type of long life road marking that has raised ribs orientated perpendicular to the direction of travel and closely spaced at regular intervals beforethe stop line. As a vehicle’s tire runs on or over an ATP road marking it provides an audible and tactile warning to the driver, improving safety by making the drivers aware of an approaching conflict. As such, ATP road markings can be a very powerful and cost effective road safety intervention.TRAFFIC CALMING

APPROACHES

Speed table used as raised crosswalk

Broom finishes, gritty surfaces, or rough texturesincrease slip resistance.

Surfaces where pedestrians travel shall be firm,smooth, stable, and slip resistant. Surfaces mustbe firm enough to support higher point loads ofwheelchair wheels, crutch tips, and other mobilityaids.• Concrete unit pavers (concrete or brick), cut stone,and tile provide acceptable surfaces. Asphalt is notdesirable in the pedestrian realm due to its highheat absorption characteristics.• Crushed fines, such as decomposed granite, canbe compacted to a sufficient level of firmness,and the use of a binding agent can further improvesurface stability and longevity.

Curb ramps with detectable warning strips.

People with sight impairments need cues as theytravel through a pedestrian system to detect changesin slopes and curb drops, and to identify trafficareas. Detectable warning strips (tactile paving) andsurfaces can provide this cue

Frequency, orientation, and detailing of buildingentrances are important to create a functionaland engaging pedestrian environment. Entrancesshould be clearly articulated, and the streetscapedesign should complement and highlight theentrance.

SURFACE MATERIALSCOHESIVE DESIGN WITH ADJACENT BUILDING FRONTAGE

Pedestrian Direction Sign in the Furnishings Zone

Signing and wayfinding should function well and establish a sustainable identity and memorable sense of place in the street network.

PEDESTRIAN AND VEHICULAR LIGHTINGLight pole wraps can be retrofitted to existing street ights.

• Pedestrian crossing should be at the same level as the footpath.• Ramps should be provided at the transition between footpath and pedestrian crossing,

when not at the same level as the footpath.• · Handrails should have opening leading to the crosswalk, and should have a width at least the width of the crosswalk.

• Clear pedestrian crossing with bold markings for visibility.• No physical obstructions on the other side of the crossing.

Footpath on opposite sides of a streetshould be connected by pedestrian crossings.· Pedestrian crossing should connect all arms of a junction.

AT GRADE PEDESTRIAN CROSSWALKS

WELL CONNECTED JUNCTION

· Tabletop crossings can be used to improve thevisibility of pedestrians.· Traffic calming measures should be takenupstream of a pedestrian crossing to slow thevehicular traffic.

The Zebra crossing should be no less than 3m (~10 ft.) wide..· A stop line shall be marked in advance of theZebra crossing (1 to 1.5 m in advance) toprevent stopped vehicles from encroachingthe Zebra crossing.

The surface level of the raised crosswalkshould coincide with level of theSidewalk,should be skid resistant,should have a slope of 1:8.

• Bollards could be used at the median access such that vehicles are discouraged from using the refuge area

• At signalized intersections with high pedestrian volume, signal phasing should include all red phase for vehicles so that pedestrians could cross safely.• Pedestrian crossing with pedestrian

push buttons, aligned in such a way that it is comfortably accessible to people on wheelchair.

PEDESTRIAN REFUGEPELICAN CROSSING

GRADE SEPARATED PEDESTRIAN CROSSWALKS

ABOVE GRADE CROSSWALK- SKYWALKS / FOOT OVERBRIDGELUJIAZUI CIRCULAR PEDESTRIAN BRIDGE IN SHANGHAI, CHINA

• Floating 5.5 meters (20 feet) above the Lujiazui Road in the Pudong district of Shanghai is a new circular pedestrian bridge that not only is outstanding in aesthetic standards, but achieves an environment-friendly purpose as well.• Built only in 2011, the pedestrian bridge allows commuter to avoid the busy traffic in the Lujiazui round-about by providing a clean and convenient platform for foot transport. The bridge also connects leisure areas such as malls and cafés to transit stations and even office buildings such as the Oriental Pearl Tower.

BP PEDESTRIAN BRIDGE IN MILLENNIUM PARK, CHICAGO

The gateway has an approximate width of 6 meters in almost all the way

This 280 meters-long (925 feet) winding bridge provides incomparable views of the Chicago skyline, Grant Park and Lake Michigan connecting Millennium Park toDaley Bicentennial Plaza

Its sloping sidewalls favor that there is no fear of vertigo by users while offering greater security..

The bridge ramp has a slope of 5% to facilitate access for people with disabilities

• Designed for pedestrians and cyclists.• Useful for crossing water/railways where there are no road bridges.• Allow safe crossing of busy roads.• Can also be used for walkways between buildings or in car parks.• Must be at least 1.2m wide (unless designed for maintenance work only), but can be as wide as needed.• Can be the simplest beam type with hand rails, or a through-truss with hand rails fixed to the two trusses.• Usually require stairways and ramps

GUIDELINES

BELOW GRADE CROSSWALK- SUBWAYS / UNDERPASS

THE UNGC PEDESTRIAN UNDERPASS, GREENSBORO,NORTH CAROLINA

$6 million railroad underpass project at UNC-Greensboro that now allows pedestrians to move safely between campus and Lee Street.

The well-lit pedestrian underpass will facilitate safer pedestrian and bicycle connection .

Multiple utilities, including sanitary sewer, domestic water, natural gas, electrical duct bank and overhead electrical lines had to be relocated.

Entry from Lee Street.Construction

Railway lines continued to function during construction. Tall glass structure acts like a landmark for the subway.

Ramped access with handrail separating bicycle and pedestrian movement.

A beautiful 16,000 sf Spanish influenced plaza was designed on the campus side to enhance the architecture of the underpass and serve for multiple activities.

The underpass itself was designed by architects with beautiful tri-color, individually painted pyramids with spiraling color schemes to enhance the lighting and design.

THE PLAZA THE TUNNEL

THE LOWLINE ,DELANCY STREET ,NEWYORK

The Lowline park will use solar technology to light and power the historic Williamsburg Bridge trolley terminal, closed in 1948, which lies beneath Delancey Street .

Vision is a stunning underground park, providing a beautiful respite and a cultural attraction in one of the world’s most dense, exciting urban environments.

RETAILProvision of retail facilities in subways reduces fear of usage and increases natural surveillance.

ARTUse of art to adorn subways not only uplifts the aesthtics but also encourages usage.

ELEMENTS OF INTEREST

The Subway must be located close to main line of travel in order to maximise use of facility.

Wide approach,subway allignments with good visibility,lighting,ventilation encourage usage.

Boulards used to obstruct motorcycles from using subway.

• The width for pedestrians should be segregated from the width for cyclists, preferably by level difference.

• Alternatively,segregation can be achieved by means of guardrailing which would serve as physical barrier to separate the footpath users from cycle track users.

GUIDELINES

• Where number of users are small,unsegregated short subway with good visibility of width 3m may be used.

• Sight distance of 4.0m or more should beprovided at corners and changes of direction.

• Access ramps and stairsmust be as wide as subway except when multiple accesses are provided.

• Landings must be provided at changes of direction and gradient.Gradient between landings must not exceed 3.5m.

• Landing between 20 steps;after 3 flights,change of direction of atleast 30 degrees.• Pedestrian ramps-5-10% gradient.• Cyclist ramps-3-5% gradient.• Escalators and elevators (1.4X1.4 min) may also be provided.

• Porous materials like faced brick and concrete avoided for walls.• Concrete soffits in ceiling to reflect light .• Floors must be cambered and transverse slope of 3% towards channels.