Wisconsin Department
of Transportation
Intelligent Transportation Systems (ITS)
Design Manual
CHAPTER 3
RAMP
METERING
December, 2000
Wisconsin Department
of Transportation
Intelligent Transportation Systems (ITS)
Design Manual
3. Ramp Metering
3.1.
Introduction & Usage
Ramp metering is the primary system element for addressing recurring freeway
congestion. Ramp meters are traffic signals placed at the freeway on-ramps. They control the
rate at which vehicles enter the mainline such that the downstream capacity is not exceeded,
thereby allowing the freeway to carry the maximum volume at a uniform speed. Though it
may seem paradoxical, by controlling traffic at the ramps such that the freeway's throughput is
maximized, more vehicles can enter from the ramps than if the mainline flow was permitted to
breakdown.
Another benefit of ramp metering is its ability to break up platoons of vehicles that have
been released from a nearby-signalized intersection. The mainline, even when operating near
capacity, can accommodate merging vehicles one or two at a time. However, when platoons
(i.e., groups) of vehicles attempt to force their way into freeway traffic, turbulence and
shockwaves are created, causing the mainline flow to breakdown. Reducing the turbulence in
merge zones can also lead to a reduction in the sideswipe and rear-end type accidents that are
associated with stop-and-go, erratic traffic flow.
Ramp metering can serve other purposes, including
•
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Discouraging drivers from using the freeway for very short trips. Ramp metering is
more likely to reduce the number of short trips on the freeway because the net
timesavings resulting from improved freeway flow will be smaller (or non-existent)
for short trips as compared to longer trips.
Providing incentives for bus ridership and carpooling by allowing HOVs (High
Occupancy Vehicles) to bypass the ramp meter. Typically, the time saving is one to
three minutes.
Ramp meters may be controlled locally based on time-of-day and day-of-week, or via
traffic responsive metering where metering is enacted based on volume, occupancy, or speed
being obtained by the local freeway detection. Ramp meter plans are stored in the controller in
the same manner as surface street intersection traffic signals.
Ramp meters may also be controlled from a central system based on ramp and mainline
traffic conditions in much the same way as surface street traffic signals use adaptive (or traffic
responsive) control. Ramp meters can be turned on and off from the operations center, or can
be controlled by central software in corridor or system-wide traffic control strategies utilizing
ramp metering algorithms to disperse traffic volumes throughout the system.
3.2.
Basic Ramp Meter Types
Ramp meters are broken into five different types, dependent upon the number of lanes
required for a location and the usage of high-occupant vehicle lanes for priority treatment. To
date, it has been the State of Wisconsin’s policy that high occupant vehicle lanes be metered for
safety reasons. The five types of ramp meters are as follows:
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SOV - single-lane ramp meter, termed Single Occupant Vehicle
SOV/HOV - dual-lane ramp meter including High-Occupant Vehicle priority
treatment
2 SOV - dual-lane ramp meter with no high-occupant vehicle priority treatment
2 SOV/HOV - three-lane ramp meter including high-occupant priority treatment
System to System Ramp Meters - a special classification of ramp meter requiring
additional considerations due to the unique nature of freeway system interchanges
3.2.1. Single-Lane (SOV) Ramps
A single lane ramp meter is used at locations where the peak hour design year volume
is 720 vehicles or less (1 vehicle every 5 seconds), provided that the existing ramp geometries
are capable of providing the required acceleration and storage. SOV ramp meters are typically
found in areas where the peak hour demand is low and an HOV lane is not justified or feasible
3.2.2. Metered Two-Lane (SOV/HOV) Ramps
Similar to a single-lane ramp meter, a single-occupant / high-occupant combination
dual-lane ramp meter should be provided for peak period ramp volumes up to 720 vehicles per
hour (1 vehicle every 5 seconds). A high-occupant vehicle priority lane is added to encourage
carpool and transit riders when the ramp is nearby a specific large employment base or trip
generator (i.e., major factory, shopping mall, etc.). An HOV lane addition is warranted when
ramps consist of high occupant vehicles (HOV) totaling 9% or greater of the total peak hour
volume.
3.2.3. Metered Two-Lane (2 SOV) Ramps
Dual lane (2 SOV) ramp meters are typically found in areas where the peak hour
demand is moderate to high and an HOV lane is not justified or feasible. This type of ramp
meter is typically used where ramp volumes exceed 720 vehicles per hour.
3.2.4. Metered Three-Lane (2 SOV/HOV) Ramps
A three-lane ramp may be designed when two single occupant vehicle lanes (720 vph
peak hour or greater in the design year) and an HOV lane are required. Three lane ramps
should be considered only under the most favorable conditions, such that the ramp will be on
tangent or a large radius curve approaching the ramp stop bar. An HOV lane addition is
warranted when ramps consist of high occupant vehicles (HOV) totaling 9% or greater of the
total peak hour volume. A three-lane loop ramp typically is not recommended due to safety
considerations.
3.2.5. Metered Freeway Connector Ramps
Freeway connector ramps are used on freeway spurs or on low-volume freeway
segments where it is more advantageous to meter one location onto a major through-route,
rather than multiple low-volume surface-street ramps upstream of the system connector ramp.
In design of freeway connector ramp meters, high-occupant vehicle lanes are typically avoided
due to geometric constraints (such as structures), ramp volume considerations, or right-of-way
constraints. However, HOV treatment on freeway connector ramps is not prohibited.
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3.3.
Intelligent Transportation Systems (ITS)
Design Manual
Ramp Meter Design Process
In the ramp meter design process, the designer must follow several steps to ensure
successful implementation and proper operational capabilities. Many of these steps, such as
highway lighting and communication requirements, must be addressed early in the design
process and not after design for the proposed location has been completed. These steps are
detailed further in subsequent sections. A flow diagram of this process is shown in Figure 3-1.
1) Collect initial data required for the proposed ramp meter design location
2) Determine the ramp meter type required for the design location
3) Evaluate geometric requirements and potential modifications for the location
4) Determine the location of the ramp meter stop bar and signals, with potential
iteration of steps 3 and 4.
5) Based on the data collected under step 1, incorporate or modify highway lighting if
not already present. This step typically is coordinated through the District’s
highway lighting engineer.
6) Determine the location of the ramp meter controller cabinet and electrical service
7) Prepare the underground infrastructure, including detectors, conduit, and
pullboxes
8) Perform cable routing to provide hardwire interconnection between the controller
cabinet and ramp meter devices such as signals, detectors, electrical service, etc.
9) Prepare signing and pavement markings as required for the ramp meter design
10) Determine the communications medium used for the proposed location
11) Revisit steps 5 through 9 until final design is complete
12) Begin the process to establish electrical service for the proposed location with the
local power company. This should be done early in the design process to establish
an acceptable electrical service location.
13) Utilizing Figure 3-23 and the information contained within Appendix A, determine
the construction details needed for the proposed design, details which need to be
modified, and new details which need to be created to provide a complete
construction plan.
14) Utilizing Figure 3-24 and the information contained within Appendix B, determine
the special provisions needed for the proposed design, special provisions which
need to be modified, and new special provisions which need to be created to
provide a complete construction plan.
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COLLECT
INITIAL DATA
DETERMINE
RAMP METER
TYPE
EVALUATE
GEOMETRIC
REQUIREMENTS
DETERMINE
STOP BAR
LOCATION
DETERMINE
CONTROLLER
CABINET LOCATION
ESTABLISH
POWER SERVICE
LOCATION
INCORPORATE /
MODIFY HWY
LIGHTING
PREPARE
UNDERGROUND
INFRASTRUCTURE
DETERMINE
COMMUNICATIONS
MEDIUM
1
PERFORM
CABLE
ROUTING
PREPARE
SIGNING AND
PAVEMENT MKG
DETERMINE, MODIFY, AND
CREATE CONSTRUCTION DETAILS
DETERMINE, MODIFY, AND
CREATE
SPECIAL PROVISIONS
1
RAMP METER DESIGN
COMPLETE
Refer to Chapter 9 on
Communications for
further information.
Figure 3-1: Ramp Meter Design Process
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3.4.
Intelligent Transportation Systems (ITS)
Design Manual
Initial Data Collection
Prior to assessing the needs of a potential ramp meter location, various data needs to be
collected to properly evaluate the proposed ramp meter location, such as:
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AM and PM peak period volumes (obtained from WisDOT)
AM and PM peak hour volumes (obtained from WisDOT)
Future peak period/hour volumes (e.g., design year projected volumes)
Site-specific issues or concerns based on an initial site visit (right-of-way, utilities,
landscape, existing signing inventory)
Local trip generators nearby the ramp (i.e., malls, factories, etc., which will have a
bearing on HOV lane addition)
Ramp vertical grades
Existing ramp width, flange to flange
Existing ramp length to painted gore
Current construction funding for the project
Without this data collection, a proper ramp meter type and design cannot be
guaranteed. The last item, current construction funding for the project, is a major concern with
respect to whether the ramp is altered geometrically, and to what extent the ramp is altered
(e.g., minor alterations, major reconstruction).
3.5.
Determination of Ramp Meter Type
Based on the initial data collection, the designer can determine the type of ramp meter
proposed. For the basis of this determination, an average vehicle length of 25 feet should be
used, which factors not only average lengths of vehicles but also spacing between vehicles.
Ramps with a known high truck volume may require a longer average vehicle length
assumption. The following considerations are provided:
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Peak Hour Volume - The ramp must provide storage for a minimum of 10% of the
current peak hour volume to ensure that the ramp meter queue does not back into
the surface street. This factor is key in determining whether the ramp will contain 1
or 2 SOV lanes. For ramp meters designed in conjunction with ramp reconstruction,
the ramp should accommodate a minimum of 10% of the design year (e.g., year
2020) projected peak hour volume. For ramp meters retrofitted to existing
conditions, a storage minimum of 5% of the current peak hour volume may be used
only with approval from the Freeway Operations Unit.
Ramp Length - In combination with the peak hour volume calculation indicating the
storage that is required, acceleration length per AASHTO Policy of Geometric Design
must be factored in with the total ramp length. These two in combination will begin
to determine the stop bar location.
Funding Availability - Once the storage and acceleration requirements have been
established, a decision must be made regarding the extent that the ramp is
physically altered. Funding availability for the construction contract may factor into
whether the ramp is widened in a retrofit scenario, or completely reconstructed to
provide the appropriate acceleration and storage distances. Ramp design
requirements should be the driving force in determining a ramp meter type,
however funding availability must be checked.
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3.6.
Intelligent Transportation Systems (ITS)
Design Manual
Geometric Considerations
Geometric requirements for metered ramps depend upon several factors, including:
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Peak hour volume which affects the storage length and width of the ramp
Percentage of high-occupancy vehicles (HOVs), if available, or local trip generators for the
ramp which affects ramp width when considering installation of an HOV lane
Design speed of the mainline for the ramp under consideration, which affects the
acceleration distance after the stop bar (acceleration distances per AASHTO Policy
on Geometric Design of Highways and Streets)
Right-of-way availability, which will factor into the length and width of the ramp
Enforceability of the ramp, which will determine whether an enforcement zone is
desired for the ramp meter (whether an HOV lane is present or not).
Construction funding, which may influence the extent to which the ramp can be
modified, affecting ramp width, length, acceleration lanes, and HOV treatment
and enforcement.
These considerations will indicate whether a ramp meter is retrofitted to existing
conditions, rehabilitated while maintaining the current alignment, or completely reconstructed.
Figure 3-2 provides recommended and minimum widths for ramp meters based on
configuration type.
Ramp With Shoulders
Ramp Meter
Configuration
SOV
2 SOV
SOV / HOV
2 SOV / HOV
HOV LANE
Traveled Way
With Curb and Gutter
Shoulder
Traveled Way
Recommended
Minimum
Inside
Outside
Recommended
Minimum
12 ft
24 ft
28 ft
40 ft
16 ft
12 ft
24 ft
24 ft
36 ft
12 ft
4 ft
4 ft
4 ft
2 ft
n/a
8 ft
8 ft
8 ft
2 ft
n/a
15 ft
24 ft
28 ft
40 ft
16 ft
15 ft
24 ft
24 ft
36 ft
15 ft
Figure 3-2: Ramp Meter Width Requirements
*See FDM Chapter 11 (Design) for Additional Information
3.6.1. Single-Lane (SOV) Ramps
Requirements for entrance ramps with one metered lane are shown in Figure 3-3 & 3-4. For
longer ramps, it may be desirable to add an intermediate queue detector to limit the delay per vehicle
proceeding through the ramp meter. The stop bar signals should be placed to allow good
visibility when traveling down the ramp.
3.6.2. Metered Two-Lane (SOV/HOV, 2 SOV) Ramps
Requirements for entrance ramps with two metered lanes are shown in Figure 3-5 & 3-6.
These designs should be used where the volumes exceed 720 vehicles per hour. The transition from
two lanes to one should be accomplished for those designs with a minimum of a 30:1 taper.
However, the transition can be accomplished with less than the 30:1 taper in retrofit situations.
Designs with less than the minimum 30:1 taper and/or 1,000-ft acceleration lane (where
restricted right-of-way or other obstructions limit the space available) must be submitted to and
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reviewed by the Freeway Operations Unit.
3.6.3. Metered Three-Lane (2 SOV/HOV) Ramps
A three-lane ramp may be designed when two single occupant vehicle (SOV) and an
HOV lane are required. Requirements for entrance ramps with three metered lanes are shown
in Figure 3-7 & 3-8. Three lane ramps should be considered only under the most favorable conditions,
such that the ramp will be on tangent or a large radius curve approaching the ramp meter limit line.
A three-lane loop ramp is not recommended. Any proposed three-lane ramp loops must be
submitted to and reviewed by the Freeway Operations Unit.
As with a two-lane metered ramp, all ramp lanes shall taper into one lane before ramp
traffic begins to merge with the mainline traffic. The transition from three lanes to one should
maintain at a minimum a 30:1 taper ratio. However, the transition can be accomplished with
less than a 30:1 taper in retrofit situations. Designs with less than the minimum 30:1 taper
(where restricted right-of-way or other obstructions limit the space available) shall be
submitted to and reviewed by the Freeway Operations Unit.
3.6.4. Metered Freeway Connector Ramps
Due to higher rates of speed, freeway connector ramps require additional safety and
advance warning considerations than found under single or dual lane metering. While many
of the design requirements remain the same for connector ramps as those described under the
previous sections, many connector ramps involve elevated structures and different geometric
requirements (due to being a mainline freeway segment rather than a grade-separated
interchange ramp). Close coordination with the Freeway Operations Unit is critical in the
design process of system connector ramp meters.
3.6.5. Enforcement Zones
Enforcement zones are placed on entrance ramp meters downstream of the stopbar to
provide a safe and visible area for sheriff personnel. These zones provide the sheriff’s
department the ability to perform the following functions:
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Enforce ramp meter operations
Enforce HOV lane restrictions (single occupant violators)
Monitor speeds on the mainline
Provide a staging area for maintenance activities
Geometric guidelines on enforcement zones are shown in Figure 3-3 through Figure 3-8.
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Figure 3-3: Ramp Meter Design Guidelines, 1-Lane Slip Ramp
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Figure 3-4: Ramp Meter Design Guidelines, 1-Lane Loop Ramp
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Figure 3-5: Ramp Meter Design Guidelines, 2-Lane Slip Ramp
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Figure 3-6: Ramp Meter Design Guidelines, 2-Lane Loop Ramp
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Figure 3-7: Ramp Meter Design Guidelines, 3-Lane Slip Ramp (Non-Separated HOV)
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of Transportation
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Figure 3-8: Ramp Meter Design Guidelines, 3-Lane Slip Ramp (Separated HOV)
Wisconsin Department
of Transportation
Wisconsin Department
of Transportation
3.7.
Intelligent Transportation Systems (ITS)
Design Manual
Ramp Meter Stopbar / Signal Placement
Ramp meter stop bar placement revolves around the following fundamental issues:
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Ramp acceleration required
Ramp storage required
Stop bar signal sight distances
Once the acceleration and storage distance requirements have been established (from
the initial data collection and determination of ramp meter type), the placement of the stop bar can
be determined. If the ramp is being widened or lengthened, the stop bar placement must also
be determined side-by-side with the geometric design of the ramp. For sight distance, the most
desirable location for a stop bar is at the end of a tangent section of the ramp. For loop ramps,
the stop bar placement typically should be near the freeway gore, provided adequate
acceleration distance is present parallel to the mainline.
While ramp acceleration distances are known entities based on AASHTO Policy on
Geometric Design of Highways and Streets, the storage distance can also be affected by the
operational intent of the ramp meter. If a very restrictive metering rate is desired for a location,
the storage distance requirement may be longer than the minimum established under
Determination of Ramp Meter Type. Under any circumstance, the placement of the stop bar for
ramp meters must be reviewed by the Freeway Operations Unit prior to proceeding with
final design and layout of the ramp.
When the use of a overhead sign support (mastarm) becomes necessary, such as a nonseparated 2 SOV / HOV ramp meter, placement of the overhead signals should be over the two
single occupant vehicle lanes, with the side-mounted Type 2 signal assembly placed at the
HOV lane. Only under the most restrictive geometric constraints should the overhead signals
be placed over one SOV lane and the HOV lane.
3.8.
Controller Cabinet Placement
Once the ramp meter type, geometric layout, and stop bar placement of the ramp has
been determined, the placement of the controller cabinet can be established. This placement
involves many factors, including:
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Visibility of the stop bar signals from the controller cabinet
Distance between the controller cabinet and the loop detectors (discussed in the
section 4.9)
Distance between the controller cabinet and the signals on the ramp
Safety of the cabinet location (do not place the cabinet on the outside of a curve)
Grades
Drainage
Maintenance Accessibility (parking availability for maintenance vehicles)
For maintenance considerations, it is very important that the stop bar signals be visible
from the controller cabinet. The distance between the cabinet and equipment is also of
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concern, since longer distances may require heavier gauge cables typically not used in standard
ramp meter design. Appendix D discusses cable sizing and voltage drop calculation. Heavier
gauge cables can be used where required, but increases the number of different cables on a
contract and increases construction costs.
The distance between the cabinet and loop detectors is also an important factor.
Appendix C provides an overview of loop inductance calculation and maximum lead-in cable
distance.
The slope of the terrain for cabinet placement must be no steeper than 4:1. Placement of
the cabinet on 3:1 slopes or steeper require grading provisions to provide a level area around
the cabinet.
3.9.
Advance Warning Sign Placement
Placement of a traditional advanced warning sign (e.g., “Ramp Metered When
Flashing”) depends upon the functional intent of the warning signs.
•
Pre-Entrance Notification – Under pre-entrance notification, the functional intent of
the sign is to warn motorists approaching the ramp that it is currently being
metered. The placement of advance warning signs under this scenario should
provide adequate sight distance along the cross street, allowing the motorist ample
time to decide whether to enter the freeway system at that location, or bypass the
ramp meter and travel along alternate routes.
•
Post-Entrance Notification – Under post-entrance notification, the functional intent
of the sign is to warn motorists upon entering the ramp that metering is currently
being implemented. The placement of advance warning signs under this scenario
should provide adequate sight distance upon entering the ramp, yet allowing
sufficient distance between the sign and estimated back of queue.
Figure 3-9 provides examples of both types of advance warning sign placement. A
minimum distance of 100-ft must be maintained between the advance warning sign and any
existing signs.
For system connector ramps, or high-speed urban interchange ramps, overhead advance
warning signs must be designed to provide additional warning of ramp meters. Overhead
advance warning signs are “blank-out” signs that read RAMP METERED, and contain 2 yellow
signal beacons above which flash alternately. Upon metering start-up, the RAMP METERED is
displayed and the yellow beacons flash. In non-metering conditions, the display is blank.
These advance-warning signs are typically installed above a freeway guide-sign, and mounted
to a full-span or cantilever sign structure. Design issues with overhead advance warning signs
include:
•
Placement - The back of the design year queue must be calculated for the ramp
meter. The overhead warning sign is placed to ensure that motorists have adequate
sight distance for the sign based on roadway alignment, and adequate perception
and reaction time based from the point of viewing the sign to the end of the ramp
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meter queue, in coordination with the vehicle’s approach speed.
New Type I Guide Signs - If a new freeway guide-sign and advance warning sign
is installed, sign spacing becomes a concern, and must be coordinated with the
District traffic/signing engineer. Typically, 800-ft minimum spacing is required
between WisDOT Type I signs.
Installation on Existing Sign Structures - If the advance warning signs are to be
placed on an existing structure, a thorough structural review must be conducted to
determine the load capabilities of the existing structure, and whether that structure
is capable of supporting the overhead advance warning sign.
Figure 3-9: Typical Advanced Flasher Assembly Placement
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Loop Detector Placement
As shown previously in Figure 3-3 through Figure 3-8, ramp meters involve the
following types of loop detectors:
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•
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Demand Loops - In District 2, a 6 x 20-ft loop is placed just upstream of the stop bar
in each metered lane. The distance between the leading edge of the loop and the
stop bar pavement marking line is 25 feet, leaving a five foot space between the
lagging edge of the demand loop to the stop bar. District 1 utilizes two 6 x 8-ft loops
in place of the 6 x 20-ft loop.
Passage Loops - In each metered lane, a 6 x 6-ft loop is placed just downstream of
the stop bar. The distance between the leading edge of the loop and the stop bar
pavement marking line is 10 feet.
Queue Loops - Queue loops should be 6 feet long (along the ramp) and sized to fit
the width of the lane(s) or ramp. Each queue loop placement is unique in its
placement upstream of the stop bar. This involves a trade-off between maximizing
ramp storage without having vehicles sit on queue loops, while at the same time
anticipating additional vehicles entering from the side street (i.e., platoons of
vehicles entering as a result of a traffic signal). The designer must consult the
Freeway Operations Unit to obtain guidance in placement of queue detectors.
Entrance Ramp Reporting Loops - A reporting loop detector (for traffic counts)
should be placed on multi-lane entrance ramps downstream of the stop bar where
the ramp narrows to a single lane prior to entering the freeway. Reporting loops
also must be placed on any non-metered entrance ramps within the interchange of
the ramp meter. Entrance ramp loops should be sized to fit the ramp such that
vehicles cannot avoid passing over the loop.
Exit Ramp Reporting Loops - Reporting loops also must be placed on any exit ramps
within the interchange of the ramp meter. Exit ramp reporting loops should be
sized to fit the ramp such that vehicles cannot avoid passing over the loop.
Turning Count Reporting Loops - Reporting loops at the entrance of a ramp meter
counting entering traffic by direction is preferred, but optional. These loops are
typically installed on a ramp that has a traffic island at the entrance separating the
directional movements.
Mainline Loops - Loops (or other appropriate detection technology) should be
placed upstream of the entrance ramp gore. These loops are used when the ramp
meter is operated locally in response to traffic conditions along the mainline.
Placement of mainline loops should also be coordinated with the spacing
considerations as documented in Chapter 5, System Detector Stations.
Loop detectors are typically illustrated at precise locations in the plan. A loop detector
chart provides additional information in the plan, such as the loop description (type), location
(station), size (in feet), and the number of turns of wire contained within the loop. Appendix C
provides information on loop inductance calculations, number of turns required, and
maximum allowable distance between the controller cabinet and loop. Mainline loops do not
require a station, since most ITS plansets do not require the contractor to establish stationing
along the mainline. In this instance, since each lane contains primary and secondary loops (for
speed data), the location is the lane number. The farthest left-hand (inside) lane on a freeway
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direction is always Lane 1, with lane number progressions increasing from left to right.
Figure 3-10 illustrates a typical loop detector chart and information provided on the
design location sheets.
LOOP DETECTOR DETAILS - RM-118
DESCRIPTION
QUEUE A
DEMAND A
DEMAND B
DEMAND C
PASSAGE A
PASSAGE B
PASSAGE C
NORTHBOUND PRIMARY
NORTHBOUND PRIMARY
NORTHBOUND PRIMARY
NORTHBOUND SECONDARY
NORTHBOUND SECONDARY
NORTHBOUND SECONDARY
REPORTING - EB MAIN STREET ENTRANCE
REPORTING - WB MAIN STREET ENTRANCE
REPORTING - HOV LANE
REPORTING - NB ENTRANCE RAMP
REPORTING - NB EXIT RAMP
LOCATION
48B+60
58B+30
58B+30
58B+30
58B+65
58B+65
58B+65
LANE 1
LANE 2
LANE 3
LANE 1
LANE 2
LANE 3
45B+80
SEE PLAN
52B+70
61B+75
SEE PLAN
SIZE
6' X 6'
6' X 20'
6' X 20'
6' X 20'
6' X 6'
6' X 6'
6' X 6'
6' X 6'
6' X 6'
6' X 6'
6' X 6'
6' X 6'
6' X 6'
6' X 12'
6' X 20'
6' X 6'
6' X 15'
6' X 10'
1
2
3
4
5
6
7
8
8
8
9
9
9
10
11
12
13
14
NOTES:
1. DEMAND / PASSAGE LOOPS STATIONED ASSUMING STOPBAR STATION 58B+55
2. ALL LOOPS ARE STATIONED TO THE LEADING EDGE
NO. OF
TURNS
3
3
4
3
3
4
3
3
5
4
3
5
4
3
3
3
5
3
Figure 3-10: Loop Detector Detail Chart
3.11.
Underground Infrastructure
When the controller cabinet, electrical service, loops, stop bar, and advanced flasher
assemblies have been placed, the underground conduit infrastructure can be designed. Issues
to keep in mind when designing the ramp meter conduit infrastructure include:
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Conduit Size - 3-Inch conduit is typically used for ramp meter raceways, since a)
cost savings between 3-inch and smaller diameter conduits is minimal, and b) 3-inch
conduit may provide for greater future expansion depending on the number of
cables and % fill of the conduit. Conduit entering electrical service pedestals must
be sized per pedestal requirements.
Conduit Fill - The size and number of conduits along a run is dependent on
percentage of fill as established by the National Electric Code (NEC). Although it
may not violate the NEC fill code, no more than 13 loop detector lead-in cables
should be designed for installation in a single 3-inch conduit. Installation of more
than 13 lead-in cables becomes difficult due to the quantity and weight of the cables.
Pull Box Spacing - Pull boxes should be spaced no greater than 200 feet within a
ramp meter. If a conduit run contains only one or two lightweight cables (e.g., loop
lead-ins), this distance can be stretched to approximately 300 feet.
Terrain - Conduit infrastructure should be designed on relatively flat (4:1 slope or
flatter) terrain. For steeper sloped terrain (3:1 or greater) , conduit may be run
perpendicular to (i.e., up or down) the slope to locations where the terrain is more
suitable for conduit installation.
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Wisconsin Department
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3.12.
Intelligent Transportation Systems (ITS)
Design Manual
Cable Routing
General
Cable routing for ramp meters involves the connection of all equipment to the controller
cabinet, including loop detectors, signal assemblies, advanced flashers, and the electrical
service electrical service. Other devices such as cameras (see Chapter 6) and blank-out signs
(see Chapter 12) may be added to a ramp meter site and require cable routing as described in
their respective chapters. When routing cables for a ramp meter, issues to consider include:
•
•
Grouping of cables - It is desirable to “group” cables within individual conduits
throughout the system based on destination. For example, given a three-lane ramp
meter with mainline detection and exit ramp loop(s), cables can be grouped such
that the stop bar cables (conductor and loop lead-in cables) occupy the same
conduit. The mainline and exit ramp lead-in cables can be grouped in a separate
conduit, while the equipment cables near the entrance ramp (5-conductor for
advanced flashers and queue/reporting loop lead-in cables) grouped in yet another
conduit. By grouping cables, the ramp meter cabling system is easier to maintain.
Separation of Power and Communication - The power distribution cable running
between the controller cabinet and the electrical service should be in a separate
conduit. Power and communication cables should not be mixed together.
Stopbar Signal Cables
The number of conductors required for the stop bar signals is dependent on the number
of lanes being metered, and the number of signals wired independently. For a five-section
ramp meter signal assembly (R-Y-G upper signals, R-G lower signals), a minimum of three
conductors is required to power the assembly. The upper and lower red indications are wired
in series, as well as the upper and lower green indications. This conductor count does not
factor the neutral return conductor, which may be designed independent of the traffic signal
conductors.
Ramp Meter Type
Wiring
Configuration
# of Conductors
Required
1 Lane Metering
Jumpered
Three Total Conductor
3 to first signal
3 Jumpered to second signal
Six Total Conductor
3 to first signal
3 to second signal
Nine Total Conductor
3 to side-mount signal
6 to overhead signal
2 Lane Metering
Independent
3 Lane Metering (nonseparated HOV)
Independent
3 Lane Metering
(separated HOV)
Independent
Nine Total Conductor
3 to first signal
3 to second signal
3 to third signal
Indications Wired
Red1, Yellow1, Green1
Red2, Yellow2, Green2
Red1, Yellow1, Green1
Red2, Yellow2, Green2
Red1, Yellow1, Green1
Red2, Yellow2, Green2
Red3, Yellow3, Green3
Red1, Yellow1, Green1
Red2, Yellow2, Green2
Red3, Yellow3, Green3
Figure 3-11: Ramp Meter Signal Conductors
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A heavier gauge conductor may be required for longer distances. The size of conductor
required between the controller cabinet and signals is dependent upon the number of signals
being wired onto the same conductor. If a ramp meter has two advanced flasher assemblies,
and a single 5-conductor is wired between the controller cabinet and the first advanced flasher
assembly, and another 5-conductor cable is wired between that advanced flasher and the
second flasher, the 2 advanced flasher assemblies are considered to be jumpered. If, however, 2
separate 5-conductor cables are run from the controller cabinet, one to each advanced flasher
assembly, the flasher assemblies are considered to be wired independently. The same can be
said for ramp control signals (stop bar signals). Typically, only single lane ramp meter stop bar
signals are jumpered. Appendix D provides guidance on voltage drop and conductor gauge
calculations.
In addition to the conductor cable routing, a wire diagram must be developed for
individual ramp meters. Traffic signal cables used in Wisconsin conform to the requirements as
established by the International Municipal Signal Association (IMSA). More specifically, as
documented in section 655 of Wisconsin’s Standard Specifications, signal cables are required to
conform to IMSA specification 20-1. IMSA 20-1 provides a 600 volt cable, solid copper
conductors with polyethylene insulation, spirally wrapped with mylar tape and a polyethylene
jacket. The individual conductors within the cable conform to a standard color code. This color
code is found in Figure 3-12.
Figure 3-13 depicts an example of a wiring diagram by the different metering types. For
each ramp meter, the cable routing must be illustrated under the “from”, “to”, and “conductor
size” columns. The head number identifies the upper or lower heads on signal displays, or the
left or right signal displays on a mastarm. For consistency in maintenance, the conductors used
for individual stop bar indications are as follows:
•
Red Indications - Red insulation color. Utilize conductor numbers 3, 8, and 13 in
Figure 3-12.
•
Yellow Indications - Orange insulation color, except when wiring the first signal in a
three-lane ramp meter. Blue insulation color is used in this instance to make
consistent use of the white striped conductors at the first signal. Utilize conductor
numbers 5, 10, and 15 in Figure 3-12.
•
Green Indications - Green insulation color. Utilize conductor numbers 4, 9, and 14
in Figure 3-12.
Advanced Flasher Assembly Cables
For advanced flasher assemblies, a single conductor is required to power the amber
signal indications. A 5-conductor cable is typically used, and the orange conductor (#5 in
Figure 3-12) is used at all times. If a set of 2 advanced flashers are wired independently, or are
jumpered together, the orange conductor is still maintained throughout the cable(s), since the
conductor is landed on the same output in the controller cabinet.
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Wisconsin Department
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Conductor
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Intelligent Transportation Systems (ITS)
Design Manual
Insulation
Color
Black
White
Red
Green
Orange
Blue
White
Red
Green
Orange
Blue
Black
Red
Green
Blue
Black
White
Orange
Blue
Red
Orange
Stripe
Color
------------------Black
Black
Black
Black
Black
White
White
White
White
Red
Red
Red
Red
Green
Green
Figure 3-12: IMSA 20-1 Cabled Conductor Color Code
A 5-conductor cable is also used for overhead advance warning signs used in system
connector ramp meter design. Since most of these signs are placed farther in advance of the
ramp meter than with advanced flasher assemblies, the cable gauge becomes crucial. If the
distance between the controller cabinet and sign exceeds 1000-ft, additional electrical
equipment (such as a relay assembly) may be required. Design of this equipment should be
coordinated with and reviewed by the State Electrical Engineer.
Loop Detectors
Each loop detector reporting to the ramp meter controller cabinet requires a lead-in
cable between the loop and the cabinet. Appendix C provides guidance on loop inductance and
maximum lead-in cable length calculations. In District 2, a maximum of 24 loops can be
housed in a 170 controller cabinet. More advanced developments with 2070 controllers (such
as those being deployed in District 1) will be capable of handling a minimum of 48 detectors in
a controller cabinet. Additional limitations on maximum number of loop inputs in a controller
cabinet may exist due to capabilities of the controller firmware.
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Wisconsin Department
of Transportation
----
----
----
----
--------------------------------COLOR CODE
FROM TO COND.HEAD
SIZE
#
Intelligent Transportation Systems (ITS)
Design Manual
Head #1
----
----
----
----
---------------------------------
Red, yellow, and green
CB1
SB1
7C
1
RED, ORANGE, GREEN
indications
2
RED, GREEN
3
RED, ORANGE, GREEN
4
RED, GREEN
SB1
SB2
7C
Head #2
Red, and green indications
CB1
FY1
5C
5
ORANGE
FY1
FY2
5C
6
ORANGE
----
----
----
----
---------------------------------
R
Y
G
R
Y
G
R
G
R
G
SB1
----
----
----
----
---------------------------------
Head #1
SB1
12C
1
RED-BLACK, ORANGE-BLACK, GREEN-BLACK
Red, yellow, and green
2
RED-BLACK, GREEN-BLACK
indications
SB1
SB2
7C
3
RED, ORANGE, GREEN
4
RED, GREEN
5
ORANGE
Head #2
5C
Red, and green indications
CB1
FY1
FY1
FY2
5C
6
ORANGE
----
----
----
----
---------------------------------
R
Y
G
R
Y
G
R
G
R
G
SB1
----
----
----
----
---------------------------------
Head #1
SB1
19C
1
RED-WHITE, BLUE-WHITE, GREEN-WHITE
Red, yellow, and green
2
RED-WHITE, GREEN-WHITE
indications
3
RED-BLACK, ORANGE-BLACK, GREEN-BLACK
4
RED, ORANGE, GREEN
5
ORANGE
SB1
SB2
12C
Head #2
5C
Red, and green indications
CB1
FY1
FY1
FY2
5C
6
ORANGE
----
----
----
----
---------------------------------
R
Y
G
Head #4
Red, and green indications
Head #3
Red, yellow, and green
indications
Head #4
Red, and green indications
SB2
DUAL-LANE METERING
CB1
indications
SB2
SINGLE LANE METERING
CB1
Head #3
Red, yellow, and green
Head #3
Head #4
Red, yellow, and green
Red, yellow, and green
indications
indications
R
G
SB1
SB2
3-LANE METERING, NON-SEPARATED HOV
----
----
----
----
---------------------------------
CB1
SB1
19C
1
RED-WHITE, BLUE-WHITE, GREEN-WHITE
2
RED-WHITE, GREEN-WHITE
Head #1
Red, yellow, and green
SB1
SB2
SB2
SB3
12C
7C
3
RED-BLACK, ORANGE-BLACK, GREEN-BLACK
4
RED-BLACK, GREEN-BLACK
5
RED, ORANGE, GREEN
6
RED, GREEN
indications
Head #2
Red, and green indications
CB25 FY21
FY21 FY20
----
----
5C
7
R
Y
G
R
G
Head #3
Red, yellow, and green
indications
Head #4
Red, and green indication
R
Y
G
R
G
Head #5
Red, yellow, and green
indications
Head #6
Red, and green indications
R
Y
G
R
G
ORANGE
5C
8
ORANGE
----
----
---------------------------------
SB1
3-LANE METERING, SEPARATED HOV
SB2
SB3
Figure 3-13: Traffic Signal Wiring Diagram Example
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Design Manual
Electrical service
The power distribution wires running between the electrical service and the controller
cabinet consist of stranded copper single conductors, cross-linked polyethylene (XLP), type
USE rated. Section 655 of the standard specifications may provide guidance on additional
requirements. The gauge of conductors must be calculated per the requirements of the
National Electric Code.
Electrical Wire Routing
The conduit system for ramp meters needs to be bonded together, due to the fact that
power cables are running within the system. Bonding all metallic components of the system
together assures that there will be no difference in voltage potential across two points in that
system. In addition, the grounded conductor needs to be run with ungrounded cables (such as
traffic signal conductors, power distribution wires, etc.), which returns the circuit’s current at
zero voltage. The bonding/grounding wires in system typically uses Electrical Wire, Traffic
Signals, No. 10, Item 65557 in the State’s Standard Specifications. The gauge of grounded
conductor must be calculated per the requirements of the National Electric Code.
There is a distinct method required for the bonding/grounding system. Figure 3-14
depicts an example of routing for both bonding wire and grounded conductor. For the bonding
system, the wire needs to be run from free standing item to free standing item (i.e., poles,
cabinets, electrical services, where the wire is attached to the item’s grounding electrode), and
then from the freestanding item to its nearest pull box. The conduit between the cabinet and
nearest pull box also needs a run of wire. At pull boxes, the bonding wire is fastened to the pull
box via a grounding lug, thereby grounding each pull box. Once all freestanding items have
been bonded together, a bonding wire needs to be installed to the last pull box in the system.
In Figure 3-14, this “last” pull box in the system is PB7 near the mainline loops. The electrical
service (MB5) is grounded with a grounding electrode, using the green wire in the power
distribution wires between the grounding lugs to the cabinet.
The pull boxes do not need to be grounded if the total voltage encountered in the pull
box is 50 volts or less. In District 2, a policy has been made to bond and ground all conduit
systems, since equipment is frequently added to various locations in the future. For assistance
in bonding and grounding of underground systems, consult the State Electrical Engineer.
The grounded conductor only needs to be run with current-carrying (ungrounded)
cables. Therefore, the grounded conductor will follow the exact same routing as described
under “Stopbar Cables” and “Advanced Flasher Assembly Cables” described previously. The
grounded conductor may be sized by individual circuit, or as a combination thereof. The gauge
of grounded conductor required is also dependent on load as documented in the NEC.
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Design Manual
*No. 10 gauge wire used as a working example. Size based on voltage drop.
Figure 3-14: Electrical Wire Routing Example
3.13. Ramp Meter Signing
Signing required for ramp meters is again dependent on the type of ramp meter being
designed. Examples of different types of ramp meter signs are shown in Figure 3-15. Usage of
these signs is explained as follows:
•
•
•
R10-6 (L or R) - These signs are placed at the stop bar. In one, two, and three laned (median
separated) metering, where side-mounted signals are used, these signs are fastened to the
signal assembly. Under three-lane (no median separation) metering, a mastarm is used for
2 lanes of signals, and the R10-6 sign on the mastarm side is placed on a wood post.
R3-11 (MOD 4 & 5)- The R3-11 HOV signs are placed on the ramp, typically near the
“entrance” of the HOV lane. If the HOV lane exceeds 400 feet in length, a second R3-11 sign
may be placed along the ramp as reinforcement of the lane restriction.
R3-10 (MOD and MOD 2) – The R3-10 HOV signs are optional for ramp meter design.
They are typically placed along the cross street, visible in advance of entering the lane.
These signs warn the motorist that the ramp ahead has a restrictive lane. District 2 has
determined that R3-10 signs are not required for ramp meter operation. However, the
designer should consult the appropriate District signing representative to determine
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Wisconsin Department
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•
•
•
•
Intelligent Transportation Systems (ITS)
Design Manual
whether these signs are appropriate for ramp meters containing HOV priority lanes.
R10-10 (L, C, or R) (MOD) - These signs are also used in conjunction with two or three lane
metering, where signal assignment by lane is needed for proper ramp meter operation. In
many instances, the operation of a ramp meter “staggers” metering, with the left lane green
while the right and/or center lane signals remain red, and vice versa.
SP-11 - This sign is placed on the advance warning sign assemblies, and is accompanied by
two yellow flashing beacons.
W4-2 (L or R) - These signs are used in conjunction with two or three lane metering, where
the ramp tapers down to one lane after the stop bar. The direction of the lane drop (i.e., the
use of W4-2L or W4-2R) must match the direction of the taper on the ramp. These signs are
typically placed between 75 and 100 feet downstream of the stop bar, depending on existing
signing, overhead sign supports, beginning of taper, etc.
W9-1 (L or R) - In the case of double tapers (e.g., tapers from 3 lanes to 1 from both sides of
the ramp), a W4-2 sign is used on one side of the ramp, with a “RIGHT (LEFT) LANE
ENDS” sign, W9-1, placed on the opposite side. This configuration is used in place of both
W4-2L and W4-2R, which would give the indication that 4 lanes are narrowing to two
lanes. The W9-1 sign should be placed on the side of the ramp with the HOV lane.
These signs are only signs typically associated with ramp metering, and do not include
signing such as R1-2 (yield), R5-57 (pedestrians prohibited), or other signing that may be
required for a particular ramp. All signing must also adhere to the Manual on Uniform Traffic
Control Devices (MUTCD). Central office sign plates must be used, and all signing must be
reviewed by and coordinated with the District Signing Engineer. Bid items for signing can be
found in Sections 634, 637 and 638 of Wisconsin’s Standard Specifications.
Figure 3-16 through Figure 3-18 details signing layouts based on ramp meter
configuration for 1 lane, 2 lane, and 3 lane ramps.
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Wisconsin Department
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Design Manual
Figure 3-15: Ramp Meter Signing
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Wisconsin Department
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Design Manual
Figure 3-16: 1-Lane Ramp Meter Signing Placement
Figure 3-17: 2-Lane Ramp Meter Signing Placement
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Wisconsin Department
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Design Manual
Figure 3-18: 3-Lane Ramp Meter Signing Placement
3.14.
Ramp Meter Pavement Marking
Pavement marking for ramp meters is dependent upon the type of ramp meter. All
ramp meters must contain 4-inch epoxy edge-lines (yellow and white). Ramp meter specific
pavement markings are shown in Figure 3-20 through Figure 3-22 and as follows:
•
Epoxy, 4-inch Lane-Line - A white, epoxy, 4-inch lane-line is used in a 12 ½ -ft
marking, 37 ½ -ft spaced pattern to separate multiple SOV lanes on a ramp meter.
Typically, only three to four “skips” are required just upstream of the stop bar,
rather than dividing the SOV lanes along the entire ramp. By doing this, motorists
establish a dual-lane queue at the stop bar, and other motorists will move into these
two queues upstream. During free-flow conditions, however, multiple lanes are not
established on the ramp. Where significant ramp curvature exists, this lane line may
need to be extended further upstream along the ramp for safety considerations.
•
Epoxy, 24-inch Stopbar - At all ramp meter locations, a white, epoxy, 24-inch stop
bar pavement marking is required across the ramp at the location of the ramp meter
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Design Manual
signals.
•
Epoxy, 8-inch Channelizing Line - For ramp meters containing an HOV lane
without physical (i.e., median) separation between the SOV lane, a white, epoxy, 8inch channelizing line is required from a point just downstream of the ramp
entrance to the stop bar. The location of the beginning of this channelizing line must
allow ample sight distance to the HOV lane to allow motorists to make the
appropriate lane change.
•
Epoxy, 8-inch Channelizing DOT Pattern - At the “entrance” of the HOV lane, a
white, epoxy, 8-inch “skip” line is used in a 5-ft marking, 5-ft spaced pattern. This
marking is established from the beginning of the channelizing line, and angled
upstream and across the ramp to the edge of pavement. When a high-occupant
vehicle enters the HOV lane, it crosses the skip line. HOV skip lines typically run
between 75-ft and 100-ft in length, dependent upon width of the HOV lane and
ramp alignment.
•
Epoxy, HOV Symbols - For the length of the HOV lane, white, epoxy, “diamond”
symbols are spaced 100-ft apart. A symbol must be within 30-ft of the stop bar. The
100-ft spacing may be shortened between symbol nearest to the stop bar and the
symbol immediately upstream to maintain this requirement. HOV symbols serve as
a distinct reinforcement of usage of the lane.
The HOV symbol is a special item not found in the State Standard Specifications. In
addition, the HOV symbol and 8-inch channelizing lines require construction details as
documented in Appendix B.
Figure 3-19: Ramp Meter Pavement Marking Details
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Design Manual
Figure 3-20: 1-Lane Pavement Marking Requirements
Figure 3-21: 2-Lane Pavement Marking Requirements
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Wisconsin Department
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Intelligent Transportation Systems (ITS)
Design Manual
Figure 3-22: 3-Lane Pavement Marking Requirements
3.15.
Highway Lighting
Ramp lighting is required for every ramp meter. The stop bar area must be lighted, and
static signing and pavement markings must be visible under all lighting conditions. WisDOT
roadway lighting guidelines can be found in Section 11-50-15 of the Facilities Design Manual.
Ramp lighting must also be coordinated through the District’s Highway Lighting Engineer. To
avoid delays in design, notify the Highway Lighting Engineer early in the design process to
determine who will perform the lighting design, along with establishing review submission
due dates.
3.16.
Ramp Meter Controller Equipment
For District 2 ramp metering installation, a Ramp Meter Processor Assembly is used,
consisting of the following devices:
•
•
Type 334 Cabinet
Type 170 controller unit
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Wisconsin Department
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•
•
•
•
•
Intelligent Transportation Systems (ITS)
Design Manual
⇒ CPU
⇒ Input/output interface
⇒ Unit chassis
⇒ Unit power supply with external power connection
⇒ Unit standby power supply
⇒ Front panel assembly
⇒ Internal system interface
⇒ Connectors C1S, C2S, and T-1
⇒ Communications system interface
⇒ Model 412C program module
⇒ Model 400 modem module
Model 200 switch packs
Model 208 monitor unit
Model 222 dual vehicle detector modules (for loop detector inputs)
Model 242 DC dual isolation modules (for microwave detector inputs or loops
shared from a different cabinet)
HOV Programmable Logic Controller (for ramp meters with HOV lane only)
The above equipment is illustrated in construction details 170pr1 through 170pr11 as
shown in Figure 3-23 and Appendix A. An HOV Programmable Logic Controller (PLC) is
added to the ramp meter processor assembly for 3 lane ramp meters equipped with an HOV
lane. Since HOV lane volume is typically low, there may not always be a queued vehicle
present in the HOV lane. Rather than grant a green light to an empty metered lane during
alternating metering, the PLC will hold the HOV lane signal red until a demand is detected
from the demand loop.
District 1 is currently developing requirements for ramp metering with model 2070
controllers. For additional information on 2070 hardware requirements, contact the State
Electrical Engineer.
3.17.
Communication Requirements
Ramp meter controllers used within District 2 are Model 170 processor assemblies,
which contain 1200 baud (bits per second) modems internal to the processor unit. The
communication medium selected for ramp meter design is open to any of the communication
types as described in Chapter 9, Communication System.
3.18. Electrical Service Requirements
District 2
A 100 Amp, 120/240 volt, single phase, three wire underground electrical service is
required for electrical service installation. Two 170 controller cabinets can be powered by a
single 100-amp service. The electrical service will be furnished and installed by the Wisconsin
Electric Power Company up to a demarcation point, typically an electrical service (meter)
pedestal. The electrical service must conform to the requirements as found in the Electric Service
and Metering Manual as issued by Wisconsin Electric. The location of the electrical service
pedestal must receive approval from the utility company. Prior to design initiation, the
designer should contact The electrical service will include two 50-amp circuit breakers rated
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Design Manual
at 22,000 AIC. The requirements for power cable between the electrical service and controller
cabinet can be found under the Cable Routing section of this chapter.
At locations which require a remotely located electrical service, a 100 Amp outside rated
breaker box with space for 6 circuits, but no main breaker, will be attached to the side of the
cabinet. Also, a 50 Amp single circuit breaker rated at 22,000 AIC will be installed within the
breaker box to serve as a local electrical service disconnect point.
Guidelines in designing the appropriate feeder cables between the electrical service and
cabinet are documented under section 3.12 - Cable Routing.
3.19.
Ramp Metering Construction Details
Construction details previously used during construction of ramp meters in District 2
are found in Figure 3-23. These details, in Adobe Acrobat format, can be found in Appendix A.
Electronic Microstation versions of these files can also be found on the ITS Design Manual CD.
3.20. Ramp Metering Special Provisions
Special provisions for items used in contracts containing ramp meters are listed in
Figure 3-24. These special provisions, in Adobe Acrobat format, can be found in Appendix B.
Electronic files of the special provisions (Microsoft Word version 7.0) can also be found on the
ITS Design Manual CD.
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File Name
cabbase
breaker
meter1
meter2
polecond
170pr1
170pr2
170pr3
170pr4
170pr5
170pr6
170pr7
170pr8
170pr9
170pr10
170pr11
cabidplq
stopbars1
stopbars2
stopbars3
pavemark
logic
flasher
signals1-2
signals3
ovhdss1
ovhdss2
advwarn1
advwarn2
oawslayt
relaydia
temprm1
temprm2
temprm3
signflsh
signhov1
signhov2
ramploop
frwyloop
frwyloop2
Intelligent Transportation Systems (ITS)
Design Manual
Description
CONCRETE BASE, CONTROLLER CABINET
CABINET BREAKER PEDESTAL INSTALLATION
FREE STANDING ELECTRICAL SERVICE AND SUPPORTING STAKE
ELECTRICAL SERVICE TO CABINET
CONDUIT INSTALLATION ON POLE, POST, OR INTO CABINET
170 PROCESSOR & CABINET DETAILS (1 OF 11)
170 PROCESSOR & CABINET DETAILS (2 OF 11)
170 PROCESSOR & CABINET DETAILS (3 OF 11)
170 PROCESSOR & CABINET DETAILS (4 OF 11)
170 PROCESSOR & CABINET DETAILS (5 OF 11)
170 PROCESSOR & CABINET DETAILS (6 OF 11)
170 PROCESSOR & CABINET DETAILS (7 OF 11)
170 PROCESSOR & CABINET DETAILS (8 OF 11)
170 PROCESSOR & CABINET DETAILS (9 OF 11)
170 PROCESSOR & CABINET DETAILS (10 OF 11)
170 PROCESSOR & CABINET DETAILS (11 OF 11)
CABINET IDENTIFICATION PLAQUE
RAMP METER STOPBAR LAYOUT
RAMP METER STOPBAR LAYOUT
RAMP METER STOPBAR LAYOUT
PAVEMENT MARKINGS
PROGRAMMABLE LOGIC UNIT DETAIL
ADVANCE FLASHER ASSEMBLY, TYPES 1 & 2
RAMP CONTROL SIGNAL ASSEMBLY TYPES 1 & 2
RAMP CONTROL SIGNAL ASSEMBLY TYPE 3
OVERHEAD SIGN SUPPORT TYPE 1
OVERHEAD SIGN SUPPORT TYPE 2
OVERHEAD ADVANCE WARNING SIGNS
OVERHEAD ADVANCE WARNING SIGNS
OVERHEAD ADV. WARNING SIGN ON CANTILEVER STRUCTURE
OVERHEAD ADVANCE WARNING SIGN RELAY
TEMPORARY RAMP METER (1 OF 3)
TEMPORARY RAMP METER (2 OF 3)
TEMPORARY RAMP METER (3 OF 3)
SIGN DETAIL
HOV SIGN DETAIL
HOV SIGN DETAIL
RAMP LOOP DETECTORS
FREEWAY LOOP DETECTORS AND PULLBOX GROUNDING
FREEWAY LOOP DETECTORS, NEW CONCRETE
Figure 3-23: Ramp Meter Construction Details
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Wisconsin Department
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File Name
integrator
documentation
temprm
cabbase
meterped
breakerbox
furnishramp
installramp
signaltype1
signaltype2
signaltype3
signaltype4
enforcedisplay
flashertype1
flashertype2
removesignal
removeflash
removepb
oaws
hovplc
loopsplice
testloop
propex
augbases
relayassembly
training
opsupport
removecable
reinstallcable
remreinstcable
powerwires
twistpair
signalcable
Intelligent Transportation Systems (ITS)
Design Manual
Description
FIELD SYSTEM INTEGRATOR, ITEM 90004
DOCUMENTATION, ITEM 90004
TEMPORARY RAMP METER, <<LOCATION>>, ITEM 90004
CONCRETE BASE, CONTROLLER CABINET, ITEM 90005
ELECTRICAL SERVICE, ITEM 90005
BREAKER BOX, ITEM 9005
FURNISH RAMP METER PROCESSOR ASSEMBLY, ITEM 9005, FURNISH
DETECTOR PROCESSOR ASSEMBLY, ITEM 90005
INSTALL RAMP METER PROCESSOR ASSEMBLY, ITEM 90005; INSTALL
DETECTOR PROCESSOR ASSEMBLY, ITEM 90005
RAMP CONTROL SIGNAL ASSEMBLY - TYPE 1, ITEM 90005
RAMP CONTROL SIGNAL ASSEMBLY - TYPE 2, ITEM 90005
RAMP CONTROL SIGNAL ASSEMBLY - TYPE 3, ITEM 90005
RAMP CONTROL SIGNAL ASSEMBLY, TYPE 4, ITEM 90005
ENFORCEMENT SIGNAL DISPLAY, ITEM 90005
ADVANCE FLASHER ASSEMBLY - TYPE, 1, ITEM 90000
ADVANCE FLASHER ASSEMBLEY - TYPE 2, ITEM 90005
REMOVING SIGNAL STANDARDS, ITEM 90005
REMOVING ADVANCED FLASHER ASSEMBLIES, ITEM 90005
REMOVE PULL BOX, ITEM 90005
OVERHEAD ADVANCE WARNING SIGN ASSEMBLY, ITEM 90005
HOV PROGRAMMABLE LOGIC UNITS (PLC), ITEM 90005
LOOP DETECTOR, SPLICE, ITEM 90005
TEST EXISTING LOOP DETECTOR, ITEM 90005
INSTALL PROPOSED CONDUIT INTO EXISTING ITEM, ITEM 90005
AUGERRED BASES, TYPE 1, ITEM 90005; AUGERRED BASES, TYPE 5, ITEM 90005
RELAY ASSEMBLY, ITEM 90005
TRANING, ITEM 90008
OPERATIONAL SUPPORT, ITEM 9008
REMOVE CABLES, ITEM 90030
REINSTALL CABLES, ITEM 90030
REMOVE AND REINSTALL CABLES, ITEM 90030
POWER DISTRIBUTION WIRE, NO 4 AWG, ITEM 90030; POWER DISTRIBUTION
WIRE, NO 6 AWG, ITEM 90030; POWER DISTRIBUTION WIRE, NO 8 AWG, ITEM
90030; POWER DISTRIBUTION WIRE, NO 10 AWG, ITEM 90030
6-PAIR CABLE, ITEM 90030; 12-PAIR CABLE, ITEM 90030; 25-PAIR CABLE, ITEM
90030
TRAFFIC SIGNAL CABLE, 5 CONDUCTOR, NO 10 AWG, ITEM 90030, TRAFFIC
SIGNAL CABLE, 9 CONDUCTOR, NO 10 AWG, ITEM 90030
Figure 3-24: Ramp Meter Special Provisions
December, 2000
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