11.5.9OotsSignalDesign.pdf

Office of Traffic and Safety Traffic Control Device Training

Traffic Signal Design

Office of Traffic and Safety Traffic Control Device Training Traffic Signal Design

2

Agenda

AM Session

Introduction to Signal Design

Discussion of Design Request

Standards and Guidelines for Signal Design

Office and Field Survey Data Collection

PM Session

Conceptual Location of Signal Design Elements

Plan Development


3

Purpose/Scope of Course

Create Stronger Base of Knowledge and

Information for Staff Working in Signal Design

Introduce Signal Design to Staff Working in

Other Disciplines

Provide Overview of SHA‟s Signal Design

Policies and Procedures

Create and Reinforce Awareness of Special

Design Considerations


4

Responsibilities of the Signal Design Engineer

Ensure that the Final Design:

Conforms with the Design Request, FHWA &

SHA Standards, and ADA & NESC Regulations

Is completed in an approved format, with all of

the elements necessary for the Contractor to

perform the work as specified in the Design

Request

Is consistent/compatible with other Construction

Plans, where applicable

Can be built within the available budget


5

Responsibilities of the Signal Design Engineer

Ensure that the Final Design:

Can be built within available right-of-way

Is not in conflict with existing or proposed utilities

Does not create environmental or property impacts

that cannot be readily mitigated

Is submitted for signatures at least one week in

advance of the PS&E date


6

Definition of Traffic Control Signal

“A traffic control signal (traffic signal) shall

be defined as any highway traffic signal by

which traffic is alternately directed to stop

and permitted to proceed.” (MUTCD;

Section 4B.01)


7

Traffic Control Signals


8


Exclusive/Permissive Left Turn

Exclusive Left Turn Arrows


9


Permissive

Split


10

Pedestrian Signals and Devices

Types

At Intersections

Midblock, Pedestrian Crosswalk Signals

Pedestrian Warning Beacons


11

Pedestrian Signal at Intersections

Pole Mounted Pedestal Mounted


12

Midblock Pedestrian Crosswalk Signals


13

Pedestrian Warning Beacon


14

Pedestrian Signals and Devices

Special Pedestrian Crossing Devices

Accessible Pedestrian Signal

Countdown Pedestrian Signal

In-Roadway Lights


15

Accessible Pedestrian Signals(with Illuminating Push Button)


16

Countdown Pedestrian Signal

The countdown timer starts at the same time as the

flashing “Do Not Walk” starts for pedestrian clearance interval


17

Special Traffic Control Signals

Flashing Beacons

Intersection Control Beacons (ICBs)

Warning, or Hazard Identification Beacons

(HIBs)

Speed Limit Sign Beacon

Stop Beacon

Emergency Vehicle Access Signals


18

Intersection Control Beacons

Used at intersections to control two or

more directions

Flashing indications may operate in two

modes:

Yellow for major street and red for all

other approaches or streets

Red for all approaches


19

Intersection Control Beacon

Mast Arm Mounted

Span Wire Mounted


20

Warning or Hazard Identification Beacons

Used to emphasize warning signs

Alert drivers when obstructions are in or

immediately adjacent to roadway

Active or passive system

Flashing indications are yellow


21

Hazard Identification Beacon(Active)


22



23



24

Hazard Identification Beacon(Passive)


25

Speed Limit Sign Beacon


26

Emergency Vehicle Access Signals

Assigns right-of-way to

emergency vehicles

When activated, traffic

signals display short

duration of quick flash

yellow followed by solid

red

Signals display flashing

yellow indications at all

other times


27

Special Traffic Control Signals

One Lane, Two-Way Facility

Lane-Use Control Signals

Traffic Control for Movable Bridges

Freeway Entrance Ramp Control Signals


28

Lane-Use Control Signals

Highway Application

Non-Highway Application


29

Traffic Control for Movable Bridges


30

Freeway Entrance Ramp Control Signals(Not Currently in use in MD)


31

Special Devices

Flag-in-the-Air Intersection Control

Device

Traffic Signal Preemption Unit (Receiver)


32

Flag-in-the-Air Intersection Control Device

Provides a highly visible control for stopping vehicular

traffic flow at a school-entering and crossing points


33

Traffic Signal Preemption Unit (Receiver)

The signal controller needs sufficient

time from the emergency vehicle

actuation to change the signal

indications

3 emitters are provided to firehouse


34

Design Request

Form

Interpretation

Origination


35

Design Request Form


36

Contract DR

preparer within

one week to

verify

information


37


38


39


40


41


42

Standards and Guidelines

Manual on Uniform

Traffic Control Devices

(MUTCD)

Application and

Placement

of Regulatory, Warning,

Guide Signs, Traffic

Signals and other

Devices

For traffic signal design:

provides information on

visibility, type of

displays, and

maintenance


43

AASHTO “A Policy on

Geometric Design of

Highways and Streets”

Provides guidance to

signal designer on:

• Sight distance

• Lane width

• Geometric design

Chapter 5 – Local

Roads and Streets -

used in signal design



44


AASHTO “Roadside Design

Guide”

Traffic Barrier W-beam Design

Clear Zone Requirements

Breakaway Support Guidance


45


AASHTO “Standard

Specification for Structural

Supports for Highway Signs,

Luminaires and Traffic Signals”

Design of Structural

Supports

Fabrication of Structural

Supports

Construction Methods

SHA has not adopted 2001

version. 1994 version still

being used.


46


SHA – Design Guidelines

SHA‟s Maryland Manual on Uniform Traffic Control

Devices

SHA’s Standard Sign Book

SHA‟s Accessibility Guidelines for Pedestrian Facilities

along State Highways

SHA‟s Guidelines for Traffic Barrier Placement and

End Treatment Design

SHA’s Traffic Control Devices Design Manual

SHA‟s CADD Users Guide


47


Maryland Manual on Uniform Traffic Control Devices

Documents SHA approved policies and guidelines for traffic

control devices along Maryland streets and highways


48


SHA’s “Standard Sign Book – Standard Signs – 2009

Revision”

Standard sign sizes, dimensions, and colors

www.marylandroads.com


49


SHA “Accessibility Guidelines

for Pedestrian Facilities along

State Highways”

Developed to create

accessible routes through

design of public sidewalks

and crossings

Provides guidance on

installation of signal-related

hardware such as:

• Cabinet

• Poles

• Pushbuttons

Provides guidance on use

and design of Accessible

Pedestrian Signals (APS)


50


SHA “Guidelines for

Traffic Barrier Placement

and End Treatment

Design”

Provides guidance on

computations and

calculations for traffic

barrier placement

Appendix has list of

approved End

Treatments


51


SHA – Standards and Specifications

SHA’s Book of Standards

SHA‟s Standard Specifications for

Construction and Materials and General

Provisions for Construction Contracts, Part III

SHA‟s Special Provisions Inserts, Special

Provisions OOTS Shelf Specs and

Engineering Change Notices by OOTS


52


SHA “Book of Standards

– Highway & Incidental

Structures”

Maintained by SHA‟s Office

of Highway Development

Provides SHA Engineering

Personnel and Contractors

an up-to-date catalog of

standards

Updates available online at

SHA‟s website

Sections of most interest to

Signal Designer are

Categories 1, 5, 6, and 8


53


SHA “Standard Specifications

(Gray Book)”

Specifications

• Description

• Materials

• Construction

• Measurement and Payment

Sections of Most Interest to

Signal Designer:

• Category 100 – Preliminary

• Category 500 – Paving

• Category 600 – Shoulders

• Category 800 – Traffic


54


Electrical Safety

Maryland High-Voltage Line Act: Article 89,

§ 58-63, Annotated Code of Maryland

National Electrical Code (NEC)

National Electrical Safety Code (NESC)


55

Maryland High-Voltage Line Act

"High voltage line" means an

electric line of more than 750

volts

Prohibits the installation of

equipment within 10‟ of a high

voltage line

Requires affected utility

companies to arrange safety

measures that ensure their

lines are guarded against

accidental contact

More stringent than National

Electric Safety Code


56

National Electrical Code (NEC) 2008

A standard published by the

National Fire Protection

Association (NFPA) and

incorporated in OSHA regulations

Provides guidance on the

installation of conductors and

equipment that connect to the

supply of electricity

NEC is revised on a three-year

cycle

2008 edition is the latest

Frequently, the Maryland High

Voltage Line Act requirements are

more stringent


57

National Electrical Safety Code (NESC)

A standard published by the IEEE

The purpose of the NESC is the

practical safeguarding of persons

during the installation, operation, or

maintenance of electric supply,

communication lines and

associated equipment

Contains the basic

provisions that are considered

necessary for the safety of

employees and the public

Revised on a four-year cycle

2007 edition is the latest


58

Office Data Collection

Latest Signal Plan(s) from TEDD

Electronic Files Preferred

Highway Design Plans

Existing and Proposed

Right-of Way Information

Send Memo to Request Right-of-Way

• Two memos if County Right-of-Way required

Utility Plans

Utility Companies

Local Municipalities

Locator Services


59

Initial Site Visit

Field Survey Equipment

Verify and Collect Existing Information

Field Survey Data

Tape and Wheel Measurements

Overhead Utility Heights

Signal Visibility


60


Safety Vest

Gloves (Waterproof)

Tape Measure

Measuring Wheel

Cable Height

Measuring Rod

Digital Camera

Hand Level

Two-Way Radios

Screwdrivers (Flathead

and Phillips)

Pick

Pliers

Flashlight

Spray Paint Can

Waterproof Chalk

Control Cabinet Key


61



62

Field Survey Data to Collect

Road and Lane Widths and

Configurations (i.e. left/

through/right turn lanes)

Turn Bays and Islands

Intersection Skew

Roadway Alignment

(Horizontal and Vertical)

Pavement Markings

Signing

Traffic Control Devices

Traffic Barrier

Curb, Sidewalks, and ADA compliance

Driveways and Entrances

Drainage Structures, Pipes, and Ditches

Utilities, including Proposed Electrical Feed

Parking

Setbacks, Buildings, Fences, and Walls

Trees and Vegetation


63

Tape and Wheel Survey

Create sketch of intersection

For signalized intersections, note locations

of signal supports and heads

For unsignalized intersections, note

potential locations of signal supports


64

Tape and Wheel Survey

Distances/Offsets (See Tab #2 for Instructions) Locate Point of Intersection (PI) at 1st leg of intersection

Record distance from PI to surface features using

measuring wheel

Continue measuring for a distance of 1,000‟ or to

Signal Ahead sign (W3-3)

Measure offset to recorded features from edge of

roadway using cloth tape while walking back toward the

intersection

Repeat steps for the other legs of intersection and for

medians


65

Tape and Wheel Survey Measurements


66



67



68



69

Overhead Measurements

Measure overhead utility line

heights on all corners where

signal structures will be

located (see Tab #2 for

instructions)

Measure vertical clearance of

existing signal heads and

span wire (should be 15‟0”

minimum)

Note where measurements

were taken on field sketch


70

Overhead Measurements

Clearance Requirements from Utility Company Cables to SHA Traffic

Signal or Lighting Structures and Cables

Cable Type

Horizontal

Clearance

(Feet)

Vertical

Clearance

(Feet)

A. Neutral Conductors, cables, guys, messengers 3 3

B. All other cables not included in A. and <750 volts 5 5

C. All other cables not included in either A. or B. 10 10


71

Skew Measurements

For quadrants that do not intersect at 90 , use

the form provided in Tab #2 to record the

appropriate measurements


72

Island Measurements

Measure the

dimensions of all

channelizing islands

and record the

measurements using

the form provided in

Tab #2


73

Signal Visibility Measurements

Measured on approaches where roadway

curvature or other site features create restriction

visibility

Use a two-way radio or cell phone for

communications during this step

Make visibility observations at 100‟ increments,

measured from the STOP line


74


First person: hold the measuring rod, extended to a

height of 18‟6” (the normal center of a signal head)

at the approximate location of either the left or right

through-traffic signal head, whichever provides the

best visibility

Second person: make the observations with eye

level at approximately 3‟6” (driver eye height) from

the middle-left side of the lane that has the most

restricted sight distance


75


Record the distance where the top of rod is no

longer visible and compare it to the minimum sight

distance for the prevailing speed of the road

(assume 10 MPH over the posted speed if not

designated in the DR)

If the sight distance is less than required, set up the

rod at a location where the required visibility can be

achieved and where it is feasible to mount a signal

head


76



77

Interior of Control Cabinet


78

Control Cabinet Components

1 - Controller Unit

2 - Bus Interface Unit (BIU)

3 - Rack-mounted Modules

4 - Power Supply Unit (PSU)

5 - Back Panel Terminal Strips

6 - Central Control Unit for

Accessible Pedestrian

Signals (APS)

7 - Malfunctioning Monitor Unit

8 - Telemetry Interface Panel

9 - Loop Detectors Amplifier

Interface Panel

10 - Fuse Box and Power Supply

11 - Flasher Transfer Relays

12 - Terminal Strip

13 - Conduit Stub-outs

14 - Night Light

15 - Telephone Modem

16 - Intersection Documentation


79

Base Mounted vs. Pole Mounted

Base Mounted

Preferred for all new traffic signals

Sufficient space for all control equipment

Provides flexibility for additional control equipment in future

Pole Mounted

Consider if there is right-of-way constraints for new signals

Preferred for temporary traffic signals


80

Signal Control Unit

Keypad for entering

information

Connectors

“A” – Provides power to

controller. As well as Inputs

and Outputs (I/O) to cabinet

“B” & “C” – Provide various

Inputs and Outputs (I/O) for

intersection control

“D” – Provides

communication, preemption

and expanded detection

capabilities


81

Bus Interface Unit (BIU)

Provides

communication link

between detector

rack and controller


82

Types of Rack-Mounted ModulesVehicle Detection

Four Channel Loop Amplifier


83

Types of Rack-Mounted ModulesVehicle Detection

Video Detector Module

Mini-Hub

Communication Hub to Controller Video Detector

Communications Interface Panel


84

Types of Rack-Mounted Modules

4 Channel Opticom Discriminator Module

for Emergency Vehicle/Bus Preemption


85

External Power Supply Unit

Supplies 24V DC

power to the Loop

Amplifier Rack


86

Back Panel Terminal Strips

Wiring terminals to hard-wire Inputs/Outputs for the

controller

Low Voltage (DC)


87

Control Unit for Accessible Pedestrian Signals (APS)

Designed to work with the

pedestrian pushbutton

APS uses the pedestrian signal

head indications

WALK indication activates the

APS


88

Malfunctioning Monitor Unit

Monitors voltage of cabinet

components to ensure that the

proper operating range is

maintained

Monitors all field colors

Prevents two conflicting green

indications from being

illuminated at the same time

Communicates with controller

via SDLC cable


89

Telemetry Interface Panel and Phone Block

2400 bps FSK 12 pair 19 AWG (voice

grade) cable

RS-232 2400 - 19.2K bps

Telemetry

Interface Panel

Phone Block

(For terminating telemetry cable)


90

Loop Detectors Amplifier Interface Panel

Connects field loops to the

vehicle detector amplifiers

Ground bus terminal provided

between each loop pair

terminal to allow termination of

loop lead-in cable ground wire


91

Fuse Box and Power Supply Strip

Allows access to main and

auxiliary breakers without

removing front cover

Supply power to utility outlet


92

Load Switches and Flasher Transfer Relays

Load Switches

Receive outputs from

controller which are

relayed to signal control

terminal strips

Converts 24-Volt DC from

controller to 120-Volt AC

for signal heads

Flasher Transfer Relays –

Flash mode

Used when Malfunctioning

Management Unit (MMU)

overrides signal system

Signal placed in flash

either manually or through

TOD program


93

Terminal Strip (Signals)

Wiring Terminals for Field Connections

Signal Heads

Pedestrian Heads

Push Buttons


94

Conduit Stub-outs in Base of Control Cabinet with Cables

Provides access for power, communications and

interconnect cables


95

Night Light

Provides light when night work

is being performed in cabinet


96

Telephone Modem

Provides communications

access from remote

location enabling SHA to

control and monitor

intersection operations


97

Intersection Documentation

Timing Charts

Cabinet Prints

Intersection Plan


98

Conduit and Cabling System Documentation(For Rebuild Projects)

Verify additional cables can be placed in

conduit by visual observation

Verify conduit is not blocked/crushed by using

chalk method to determine whether existing

cable can move


99

Conduit and Cabling System Documentation(For Rebuild Projects)

(Handhole with stubouts and cables)


100

Conduit Fill

SHA‟s allowable conduit fill

percentages (based on cross-

sectional area)

25% for new

installations

40% is the maximum

when using existing

systems

Reasons to limit conduit fill

Limit excessive heat

production in conduit

Constructability

Wires

Conduit


101

Initial Site Visit

Identify Conceptual Locations of Design

Elements

Poles

Signal Heads

Cabinet(s)

Pedestrian Pushbuttons, Sidewalk Ramps

Crosswalk and Roadway Markings

Signs

Vehicle Detectors


102

Pole Types Mast Arms

Preferred by SHA

Lengths/combinations of mast arms used by OOTS

Single Arm (Feet) Double Arm (Feet)

38 50/50

50 50/60

60 50/70

70


103

Pole TypesMast Arms

• 10‟ minimum embedded foundation

• Per the MD-MUTCD, the top of the signal housing located over a roadway shall not be more 25.6 feet above the pavement


104

Pole TypesSpecial “T” Poles

Special “T” type poles used to avoid

overhead conflicts

Doesn‟t have to be used at all four corner of

the intersection to maintain consistency

unless:

Aesthetic Concerns

Engineering Judgment (i.e. using on more than

one corner)


105

Pole TypesSpecial “T” Poles

* 15‟ minimum clearance in MUTCD


106

Pole TypesStrain Poles

May be needed at very wide intersections

May be used for consistency with other adjacent

signals

May be used temporarily

Span Length (Feet) Strain Pole Size (Inches x Feet)

Less than 150 12 x 30

150 feet to 200 12 x 32

More than 200 14 x 32 (two-ply wall)

STRAIN POLE SIZE BY SPAN LENGTH


107

Pole TypesStrain Poles

Per the MD-MUTCD, the top of the signal housing located over a roadway shall not be more then 25.6 feet above the pavement


108

Pole TypesPedestal Poles

Primary usage

Pedestrian signal heads

Left turn signals in median of divided highways

(breakaway)

Push buttons (36” above ground)

In special cases

Utility conflicts

Supplemental signals

Some historic districts

Nominal Pole Heights (including Transformer Base)

10‟, 14‟, or 20‟


109

Pole TypesPedestal Poles (Transformer Base)


110

Pole TypesPedestal Poles (Breakaway Coupling)


111

Pole TypesPedestal Poles


112

Pole Location Criteria

2‟ minimum from face of curb to face of pole (Closed-

section road-urban environment)

6‟ minimum from edge of road to face of pole (Open-

section road)

6‟ from face of building (or vertical obstruction) to face

of pole

5‟ minimum to gas lines from outside of foundation

4‟ minimum to face of existing pole foundations and

back of w-beam to the face of pole

Within SHA‟s Right-of-Way

Must meet ADA requirements for accessible design

Corner sight distance not impacted


113

Pole Location Criteria


114

Signal Head Location Assumptions

Number of Heads

Minimum of two heads per movement

Third head is required when

• 85th percentile speed greater than 50 mph and

• Distance to last signal is greater than 3 miles


115

Signal Head Location Assumptions

Location of signal

heads

Minimum distance

from stop line is 40‟

Maximum distance

from stop line is 120‟

with no near-side

signal


116

Signal Head PlacementPermissive Phasing


117



118



119



120

Signal Head PlacementExclusive/Permissive Phasing


121



122



123



124

Signal Head PlacementExclusive Phasing


125



126



127



128

Signal Head PlacementSplit Phasing


129



130



131

Control Cabinet Location Considerations

Proximity to power feed

Proximity to interconnect

conduit system

Corner sight distance not

impacted

Signal indications can be

viewed from cabinet

Avoid susceptibility to run-off-

the-road accidents

Sufficient right-of-way

available to permit easy

access

Avoid blocking ADA path


132

Pedestrian Pushbuttons

Pedestrian Pushbuttons should be located as

follows

Adjacent to a level all-weather surface to provide

access from a wheel chair, and where there is an all-

weather surface, wheel chair accessible route to ramp

(max. 18” reach to pushbutton)

Within 5‟ of crosswalk extended

Within 10‟ of edge of curb, shoulder, or pavement

• But a minimum of 2‟ from face of curb

Provide a minimum of 32” of clearance

Tactile arrows oriented parallel to crosswalk to be used


133

APS Worksheet


134

Pedestrian Pushbutton Locations(Design to accommodate APS)


135

Pedestrian Pushbutton Locations


136

Pedestrian Pushbutton Locations(Median Pushbutton Issues)

Length of crossing

Signal Phasing

Number of pedestrians

Width of Median


137

Sidewalks

Minimum width is 60”

Minimum width at isolated pinch points, maximum 24” in length, is 32”

*This does not include the top of curb

Maximum cross-slope is 48:1 (2%)

Anything less must have an approved design waiver


138

Sidewalk Ramps

Legislation requires that a ramp be provided at pedestrian walkways, which are intersected by curbs. SHA standard ramps are generally compliant with the currently accepted guidelines. However, the standards do not address all potential conditions and constraints. Additional ramp designs are provided within the referenced guidelines.

In cases where none of these standards or designs is appropriate, the designer is required to provide detailed designs for the special ramps.


139

Sidewalk Ramps

Maximum running slope is 12:1

Along existing roadways, all slopes shall be measured independent to the surrounding terrain. Therefore, the length of the ramp is solely dependent on the height of the curb.

6” Curb – 6‟ Ramp Length

8” Curb = 8‟ Ramp Length


140

Sidewalk Ramps

(Preferred Design)


141

Sidewalk Ramps

Flared Design – Typical for Ramp with Wide Sidewalk


142

Sidewalk Ramps

Tapered Design – Typical for Ramp with Narrow Sidewalk


143

Median Treatments


144

Sidewalk Ramps


145

Sidewalk Ramps


146

Crosswalks, Stop Lines, and Pavement Markings


147

Pavement Markings

Lane Drop Markings


148

Pavement Markings

Double Left Turn Lane

Markings


149

Pavements Markings

Turn Bay Markings


150

Roadway Signing

Overhead Street Name Signs D-3(1) *See

Standard Sign Book

Installed on all legs of intersection

Mounted near left and far right, dual faced

When different street names on either side

of intersection, left side name on left sign

and right side name on right sign

20” max height

Dual faced if 16” or 20”


151

Roadway Signing


152

Roadway Signing

Route Marker Assemblies

Facing side street intersections along numbered

routes

Mounted near right and far left, preferably on

signal support

Near side shield assembly – 24” for 2 digits or 30”

for 3 digits x 48” high

Far side assembly – 36” for 2 digits or 48” for 3

digits x 72” high


153

Roadway Signing

Route Marker Placement


154

Roadway Signing

Route Marker Placement


155

Roadway Signing

Signal Warning Signs W3-3

Install when signal visibility requirements are not met

Install new panel W16-14(1) with two flags atop the sign panel for new installations; sign to remain for 1-3 months

Required on side road approaches over 35 MPH


156

Roadway Signing

Advance street name signs required on all approaches

D3-2

D-3(2)

Note: If D3-2 is the permanent sign to remain, for all new traffic signals

install both D3-2 and W3-3 with “new” plaque signs and District forces

will remove W3-3 sign after 90 days.


157

Roadway Signing

Pedestrian Push

Button Sign R10-3(1)

Name of street being

crossed, designated

on top section of sign

Make note in

construction details


158

Types of Detectors

Non-intrusive (preferred)

Video detection

Non-Invasive Microloop Probe detectors

Intrusive detectors

Inductive loop detectors

Microloop probes


159

Video Detection

One video camera is required per

intersection approach (presence

detection)

At locations with traffic signals on mast

arms, the video camera should be:

Attached to mast arm on the far-side

of intersection

At locations with traffic signals on span

wire, the video camera should be

located on the strain pole or lighting

bracket. Video detection is not

effective if poles are set back

significantly from the roadway.Video Camera Installation

http://www.roadtraffic-technology.com/contractors/detection/image/


160

Video Detection

Installation Issues:

Lighting brackets

Overhead utilities

Presence and passage detection

System detection

Distance from camera to detection zone

Shadow effects

Part-time signals (school signal)


161

Non-Invasive MicroLoop Probe(Preferred for Passage Detection)

Used for passage detection on mainline and minor approaches

and located based on dilemma zone chart

Installed in 3” diameter schedule 80 PVC tube

Sense disruption of Earth‟s magnetic field

Used exclusively for passage detection

Used in lieu of vertically mounted probes

Used in high speed, high volume traffic conditions

Used if resurfacing is anticipated in the near future

Used if lane patterns will shift

Handhole installed with long dimension perpendicular to edge

of road

Available lead-in lengths are 500‟ and 1,000‟ feet


162

Non-Invasive MicroLoop Probe


163

Non-Invasive MicroLoop Probe


164

Inductive Loop Detectors

Loop detectors create an electrical field at the

surface of the roadway

Connected to controller via two conductor

aluminum shielded cables; creates a continuous

run of wire from controller to loop detector and

back again

Need to avoid surface features (manholes, gas

valve, etc.)

Avoid installing in deteriorated pavement

(susceptible to failure)

Avoid long lead-in cables (susceptible to failure)


165

Inductive Loop Detectors

Two types

Large area detectors

• Stop line presence detection (6 feet x 30 feet)

• Queue detection (6 feet x 20 feet)

Small area detectors

• System or Passage detection (6 feet x 6 feet)


166

Large Area Detectors

Located 12” behind the stop line

Quadruple design

3 longitudinal sawcuts

Figure 8 wrap pattern

• 3-6-3 in asphalt

• 2-4-2 in concrete

Used for presence detection on minor approaches or ramps and mainline approaches with left or right turn phasing

Labeled „Delay Output‟ when used for exclusive right turn lanes or left turn lanes with exclusive/permissive phasing


167

Small Area Detectors

Used for passage detection on mainline and minor

approaches and located based on dilemma zone

chart

Used for system detection on mainline and located

beyond intersection

Four turn wrap pattern


168

Inductive Loop DetectorsSawcut


169

Microloop Probes

Sense disruption of Earth‟s magnetic field

Used exclusively for passage detection on mainline and

minor approaches; located based on dilemma zone chart

Grouped in sets of 3, which are installed in 1½” diameter

holes drilled vertically in the road surface

Not to be used in the following situations:

In concrete pavement or tunnels

Around power lines or rail lines

On bridge decks

Lead-ins run in a 3/8” inch wide slot from probe set to

controller (available lead-in lengths are 500‟ and

1,000‟)


170

Dilemma Zone Chart

Travel Speed (MPH)

Distance from STOP Line (Feet)

MAJOR STREETSMINOR

STREETS

25 180 N/A

30 220 90

35 255 90

40 295 90

45 330 200

50 365 220

55 405 240

60 440 285


171

Handhole Installation

Should not be placed at a low point

Maximum handhole spacing is 200‟


172

Conduit Installation Methods

Trenched - in grass or dirt

Bored (directional-drilled) - under pavement

Must test pit if crossing utilities

Slotted - in pavement surfaces where it

cannot be bored (utilities or constructability)


173

Conduit System

Schedule 80 PVC conduits are used for most runs

between handholes, controller and pole bases

2 or 3 inch minimum conduit trenched

3 or 4 inch minimum conduit bored/slotted

Detector sleeves are used from handhole to edge of

travel lanes

1 inch liquid-tight flexible non-metallic conduit (runs

less than 6‟)

1 inch galvanized electrical conduit (runs greater

than 6‟)


174

Conduit InstallationBored Under Pavement


175

Conduit InstallationConsiderations

Underground utilities (need to test pit)

Boring requires 20‟ of clearance for boring

machine

Slope – will hand digging be required?

Sidewalk – need to repair

Location of driveways

Has roadway been recently resurfaced or

scheduled to be?


176

Preemption Equipment

Identify Preemption Equipment locations for

Firehouses, Train Crossings, Emergency Vehicles,

Buses

Push Button

Opticom Receivers

• Optimal line of sight is 1,500‟

• Consider measures to clear queues for emergency

vehicles

Coordinate method of actuation with fire house chief

Hard-wire signal if within 800‟ of intersection


177

Potential Utility Conflicts

Insulated Primary Cable is less than 10‟ from signal cable

Signal designer

responsible for

modifications

needed to meet

standards

Arrange meeting

with utility

companies if

conflict cannot

be avoided

and/or cost for

relocation


178

Avoiding Utility Conflicts

Insulated Primary Cable is less than 10‟ from signal cable

Use special “T”

type pole or cut

mast arm pole

to 21‟ to avoid

some overhead

conflicts

Install

underground

conduit system

to avoid

existing

overhead

conflicts


179

Electrical Service

Identify electrical facilities in project area

TEDD Project Manager to prepare Power Location

form letter (except in District 4 where TOD will

prepare). Letter should include 3 copies of a plan

highlighting the proposed power feed location.

Base Mounted Transformer Pole Mounted Transformer


180

Electrical ServiceOverhead

Base Mounted Cabinet Pole Mounted Cabinet


181

Electrical ServiceUnderground (Preferred)

Base Mounted Cabinet

(Preferred method for underground electrical service)

(Alternate method)


182

Base Map

From available plans/plats, site visit data

(tape and wheel survey) or by professional

surveyor, develop the base map, showing:

Roadway Geometrics

Existing Topographic Features

• Poles, Signal Heads and Cabinet (Rebuild

Projects)

• Sign Structures, Crosswalks and Roadway

Markings

• Detectors and Utilities, including Cable Heights

Right-of-Way Lines


183

Roadway Geometrics


184

Existing Topographic FeaturesPoles, Cabinet, and Signal Heads


185

Existing Topographic FeaturesSigns, Crosswalk, and Roadway Markings


186

Existing Topographic FeaturesDetectors and Utilities (with Cable Heights)


187

Right-of-Way


188

Preliminary Investigation (PI) Plan Development

Add field-located, proposed equipment to the

Base Map:

Signal Poles, Head Locations and Cabinet

Sign Locations and Numbering

Pedestrian Pushbuttons, Sidewalk Ramps,

Crosswalks and Roadway Markings

Vehicle Detectors

Lighting (Not applicable at Sample Location)

Pre-emption Equipment (Not applicable at

Sample Location)

HIB‟s (Not applicable at Sample Location)


189

Field LocatedProposed Signal Poles, Heads, and Cabinet


190

Field LocatedProposed Sign Locations and Numbering


191

Field LocatedProposed Ramps, Crosswalks, and Roadway Markings


192

Field LocatedProposed Vehicle Detectors


193

Title Block with Intersection Name


194

North Arrow Note

Typically located in the upper left corner of plan

Typically oriented up (i.e., above the horizontal

axis)

Note assumed direction of major street, either

EW or NS (basis for numbering signal

indications)


195

Signal Head LegendSample


196

Signal Head Numbering

Numbered on the plan uniformly using the following

criteria:

Mainline signals numbered first

• If Mainline runs in a north-south direction, signal heads facing

northbound traffic are numbered first

• If Mainline runs in an east-west direction, signal heads facing

eastbound traffic are numbered first

Minor roads are numbered next using the same rules as above

Signal heads are numbered in increasing order from left to right

Near-side heads are numbered first on each approach

Pedestrian heads and signs are numbered last using the same rules

as above


197

Signal Head Numbering


198

Sign LegendSample


199

NEMA Phasing Diagram

Typically located in upper right hand corner of

the plan

Follow NEMA Phasing Number Convention

Major Street

• Left turn signals (Phases 1 and 5)

• Thru signals (Phases 2 and 6)

Minor Street

• Left turn signals (Phases 3 and 7)

• Thru signals (Phases 4 and 8)


200

NEMA Phasing Number Convention

Main Street direction based on North Arrow

For split phasing, use Phases 3 and 4 only

for the side streets

At a T intersection, side street is Phase 4


201



202



203



204

NEMA Phasing DiagramSample

Connect the phase circles using the appropriate type of line

Solid line – phases do not operate concurrently

Dashed line – phases may operate concurrently


205

Final Design

Additions/Refinements to the PI Plan

Quantities and Cost Estimates

Specifications

Final Design Check

Final Review Meetings

Submission Requirements


206

Additions/Refinements to the PI Plan

Signal Plan Sheet

Detailed Plan

• Revisions to Reflect PI Meeting Comments

• Handhole and Conduit Layout

• Dimensions to Proposed Equipment

Construction Details

Special Notes

Revision Block

General Notes


207

Detailed Plan

Verify feasibility of field-located equipment

Add dimensions to equipment and pavement

markings

Add Construction Detail Letters and Special

Note References


208

Detailed Plan


209


Provides sufficient information to guide the Contractor in constructing the project in accordance with the design

Use letter identification from A to ZZ, as many as needed, corresponding with the plan sheet

Initially, group notes according to proposed features (for example: poles, conduit, handholes, pavement markings, removal of existing devices, etc.)

Letters are shown in circles on the plan

Same letter may appear more than once (e.g.

install handhole note will appear many times)


210



211

Special NotesSample

Instructions to the Contractor on construction methods

May address recurring issues (e.g. not blocking view of existing

signals for rebuild project) or project specific issues (e.g. be

particularly cautious when working around a specific utility)


212

Revision Block Sample

Includes previous revisions from latest record plan

Describes proposed revisions - Identified with next letter in

the alphabet


213

General Notes Sample

Typical General Notes

Disclaimer regarding overhead/underground utility information

Instructions for sidewalk repair if damaged

Instructions for equipment removal

ADA/APS compliance notes

Foundations installed at proper grade


214

Signal Plan Sheet


215

Typical General Information Sheet


216

Project DescriptionSample

Type of work planned

Intersection location and directional assumptions

Intersection operation

Controller requirements and phone line installation requirement

APS notes


217

MOT ReferencesSample

List the applicable temporary traffic control typical

applications from SHA‟s Book of Standards –

MD 104 Series


218

Project ContactsSample

The names and titles of the following SHA personnel

Assistant District Engineer – Traffic

Assistant District Engineer – Maintenance

Assistant District Engineer – Utilities

Chief, Traffic Operations Division

Utility Company Representative


219

Signal Head Wiring

Use 7 conductor cable for combinations of 3, 4, or 5

section signal heads serving one direction

Use 5 conductor jumper cable for 3 section heads

For exclusive left-turn phasing, use (2) 7 conductor

cables, one for the thru heads and one for the turn

heads

Use 5 conductor cable for each pedestrian signal

head

Use 2 conductor cable for all pushbuttons


220

Electrical Service Wiring

Coordinate with utility company to determine

the appropriate electrical service to request

Use (3) 1 conductor cable, No. 8 AWG-

THHN/THWN from metered service pedestal

to cabinet

Use (3) 1 conductor, 2/0 cables from metered

service pedestal to utility pole when getting

service from Pepco


221

Detector Wiring

For Loop Detectors

Use a separate 2 conductor (Aluminum

shielded) cable for each loop detector

For Video Detection

Use control cable for each video detection

camera

Specify cable lead-in length required upto

500‟


222

Wiring DiagramSample

Diagram shows electrical cable routing for:

Signal heads

Luminaries

Detectors

Push buttons

Power

Communications

Control cabinet


223

Wiring DiagramSample


224

Wiring Types and Sizes Used by SHA

Device/Application Cable Type Size

Pedestrian Push Button 2 Conductor Electrical Cable No. 14 A.W.G.

Photocell; Single Head HIB 3 Conductor Electrical Cable No. 14 A.W.G. (*)

Pedestrian Signal Head 5 Conductor Electrical Cable No. 14 A.W.G.

1 and 2-Section Signal Heads, 3-

Section Head with Arrows, Jumper

Wire

5 Conductor Electrical Cable No. 14 A.W.G.

4 and 5-Section Signal Heads 7 Conductor Electrical Cable No. 14 A.W.G.

“Red Signal Ahead” HIB 12 Pair Jelly Filled No. 19 A.W.G.

Loop Wire 1 Conductor in 1/4" Flexible PVC Conduit No. 14 A.W.G.

Loop Detector Lead-In Cable 2 Conductor (Aluminum Shielded) No. 14 A.W.G.

Micro-Loop Probe Sets 1 Conductor Micro-Loop Lead In No. 22 A.W.G.

Opticom Detector 4 Conductor Opticom Detector Cable No. 20 A.W.G.

Roadway Luminaire 2 Conductor Electrical Cable Type T/C No. 12 A.W.G.

Interconnect (Underground) 12 Pair Jelly-Filled No. 19 A.W.G.

Interconnect (Overhead) 12 Pair Self-Supporting No. 19 A.W.G.

Grounding Stranded Bare Copper Ground Wire No. 6 A.W.G.

Power Feed 1 Conductor Electrical Cable No. 4 A.W.G. or No. 8 A.W.G.

Electrical ServiceSize/type not shown but designated as “PS” between the power source and controller

cabinet.

Telephone Service 5 pair No. 22 A.W.G.


225

Grounding

Mast Arm Installation

Run continuous ground:

• Between control cabinet and handholes containing 110V

AC cables

• At the bases of mast arm pole structures

Span Wire Designs

Run continuous ground:

• From strain poles to the ground rod and nearest handhole

• From pedestal poles to the ground rod and nearest

handhole


226

Grounding


227

Check Conduit Fill


228

Conduit Fill Limits


229

Phase Chart

Along top of chart, show numbered signal heads

In left-hand column, list sequence of NEMA signal

phases and change intervals

In middle of table, show the signal indications for

each signal head by phase

In the far right-hand column, show movements

being served by each phase diagrammatically and

those that are stopped

Below chart, add special notes as required


230

Phase ChartSample


231

Equipment List

List A: Equipment Supplied by SHA

4-Channel Loop Detector Amplifiers

Cabinet Intersection Monitor (size 5 or 6)

Cabinet Master with Telemetry

Controller

Video Interface Equipment

Sheet Aluminum Signs (including hardware)


232

Equipment List

List B: Equipment Supplied and/or Installed by the

Contractor

Format Varies by Construction Type:

• Areawide Contractor

• SHA Forces

• Insert Project

Items not appearing in Construction Details or

Wiring Details:

• Maintenance of Traffic


233

Equipment List

List C: Equipment removed by Contractor

Used when existing Controller Equipment is being

replaced

Contact SHA Signal Maintenance Shop to pickup

Controller and Auxiliary Equipment

All other equipment shall become property of the

Contractor


234

Equipment ListsSample


235


SHA “Category Codes”

Provides a list of item

numbers to be used

when preparing an

estimate (insert

projects)


236


Quantity Takeoff

Estimating Tables and Shortcuts

Documentation


237


Many items can be directly measured or counted

Signal Supports

Signal Heads per Section

Microloop Probe Sets

Cabinet/Controllers

Controller/Distribution equipment

Conduit

Sawcut

Luminaries

Bracket Arms

Removal of Marking (Letter or Arrow)

Signs

Pavement Markings


238


Cable Measurements

Use total measured quantity plus 10%

(accounts for handholes, cable slack,

connections, splices, and drip loops)

Include pole height in the measurements

when cable runs from ground level to

overhead and sag on span wire

Loop detector measurements


239


LOOP WIRE ESTIMATE CHART

Loop Size # Turns Wire Length (Feet)1

6’ x 6’ 4 96

6’ x 30’

3-6-3 396

2-4-2 264

6’ x 20’

3-6-3 286

2-4-2 184

1 2 times the distance from detector to the handhole + 5% for the total length


240

Quantities and Cost EstimatesConcrete for Pole Foundations

FOUNDATION CONCRETE ESTIMATE CHART

Pole Type Arm Length or Pole SizeConcrete

Required

Pedestal 10 feet or 14 feet 1

Strain

12 inches x 30 feet 3

12inches x 32 feet 5

14 inches x 32 feet 5

Mast Arm

38 feet Single 3

50 feet Single and Twin 3

60 feet and 70 feet Single 5

50 feet/60 feet and 50 feet/70 feet Twin 5


241


Wood Posts

Required length per post equals

height of the sign + 7 feet (clearance

to ground) + 5 feet for 4” x 4” or 4” x

6” posts or 6 feet for 6” x 6” or 6” x 8”

posts (embedment).

Round up to the next whole number.


242

Cost Estimating

Equipment List A:

Use the latest published rates from TEDD

Equipment List B:

Construction by areawide Contractor

• Use contract bid prices

Construction by roadway Contractor (insert project)

• Use SHA Price Index and Bid Tabulations from recent contracts

• Estimator

• Industry trends


243

Cost Estimating


244

Specifications

Standard Specifications

Special Provisions

Spec Manager

Shelf Specifications

Interim Specification Amendments (ISAs)


245

Standard Specifications

SHA “Standard Specifications

(Gray Book)”

Specifications

• Description

• Materials

• Construction

• Measurement and Payment

Standards Specifications can

only be modified by the signal

designer through a special

provision


246

Shelf Specifications

OOTS Shelf specifications are only available on

SHA‟s intranet website

Shelf Specifications from Spec Manager


247

FileName Description Section No

107MOD2001AW.DOC SECTION 107 CONSTRUCTION STAKEOUT 107

107MOD2001INSERT.DOC SECTION 107 CONSTRUCTION STAKEOUT 107

804.DOC SECTION 804 - GROUNDING 804

806MOD2001.DOC SECTION 806-LUMINAIRES AND LAMPS 806

BALANCE.DOCCATEGORY 950 - TRAFFIC MATERIALS

SECTION 950.15 TRAFFIC SIGNAL HEADS950

CATCUMOD2001.DOCCATEGORY 800 - TRAFFIC

CATALOG CUTS AND WORKING DRAWINGS800

DUCT.DOC SECTION 950.06-ELECTRICAL CABLE AND WIRE 950

F&IMAST2003.DOCCATEGORY 800 - TRAFFIC - MAST ARMS AND MAST ARM POLES -

SINGLE, TWIN AND TRIPLE800

F&IPEDL2003.DOCCATEGORY 800 - TRAFFIC - GALVANIZED TRAFFIC SIGNAL

PEDESTAL POLES AND TRANSFORMER BASES800

F&ISTRA2003.DOCCATEGORY 800 - TRAFFIC - GALVANIZED TRAFFIC SIGNAL

STRAIN POLES800

FOUNDATIONS.DOC

CATEGORY 800 - TRAFFIC - SECTION 801 - CONCRETE

FOUNDATIONS (NOTE: CORRECTION REGARDING ANCHOR

BOLTS)

801

INTERIMAUDIBLEPED.DOCCATEGORY 800 - TRAFFIC - AUDIBLE/TACTILE PEDESTRIAN

PUSHBUTTON STATION AND SIGNS800

LED_SIGNALS.DOC CATEGORY 800 - TRAFFIC - LED TRAFFIC SIGNAL MODULES 800

OOTS Shelf Specifications


248

OOTS Shelf Specifications

FileName Description Section No

NEWPAINT2.DOC CATEGORY 800 - TRAFFIC PAINTING NEW GALVANIZED STRUCTURES 800

NON-INVASIVE.DOC

CATEGORY 800 - TRAFFIC - NON-INVASIVE, MAGNETO-INDUCTIVE

MICROLOOP DETECTOR - THIS SHOULD BE USED IN CONJUCTION WITH

SHELF TYPICAL 815.03

800

REDSGLED.DOC SECTION 800 - RED SIGNAL AHEAD LED SIGNS 800

REM_SAL2001_1.DOCCATEGORY 800 - TRAFFIC SIGNAL EQUIPMENT TURN ON, PICK UP,

REMOVAL AND MAINTENANCE800

REMOVESIGNS.DOCCATEGORY 800 - TRAFFIC - SECTION 822 - REMOVE AND RELOCATE

EXISTING SIGNS AND SIGN STRUCTURES822

REPAINT_WEATHERED.DOCCATEGORY 800 - TRAFFIC - RE-PAINTING PREVIOUSLY PAINTED

GALVANIZED STRUCTURES800

SIGNLIT2001.DOC CATEGORY 800 -SIGN LIGHTING SYSTEM 800

SPANWIRE.DOC SECTION 819 - STEEL SPAN WIRE 819

TEMPWETTAPE.DOC TEMPORARY WET REFLECTIVE PAVEMENT MARKINGS 104

TUBESIGN2MOD2001.DOCCATEGORY 800 TRAFFIC

SQUARE PERFORATED TUBULAR STEEL POSTS800

UTIL-CON-MOD2001.DOCCATEGORY 800 - TRAFFIC

UTILITY CONNECTIONS, AND UTILITY STAKEOUT800

VIDEO_DETECTION.DOC CATEGORY 800 - TRAFFIC - VIDEO TRAFFIC DETECTION SYSTEM 800

WEATHERED_PAINT.DOCCATEGORY 800 - TRAFFIC - PAINTING WEATHERED GALVANIZED

STRUCTURES800


249

Interim Specification Amendments

Interim Specification Amendments

Inserts are available from SHA‟s external

website – http://www.sha.state.md.us/


250

Final Design Checklist

Use Traffic Signal

Checklist for TEDD

Projects (See Tab 3)

Must be submitted with

Final Review Plans

11.5.9OotsSignalDesign.pdf

Documents

highway traffic signal

turn arrowsoffice of

pse dateoffice of traffic

signal design engineerensure

final design

devices types

session introduction

elements necessary