2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS CATEGORY 100 PRELIMINARY SECTION 104.29 — TRUCK MOUNTED VARIABLE MESSAGE SIGN (TVMS)
104.29.01 Description
Furnish, install and relocate a portable, self-contained, truck mounted, variable message sign.
104.29.02 Materials
Each unit shall contain the work vehicle structural support system, sign panel assembly, lift mechanism, power supplies, sign mounted controller, and ancillary equipment. All materials for TVMS shall be like new, corrosion resistant, and unaffected by water spray, salt, oil, gasoline, and all other contaminants in the quantities normally found along the edge of the traveled roadway. The TVMS construction, materials, and operation shall meet NFPA, UL, and NEC. Ensure that sign messages are visible and legible for a distance of 900 ft from any point along the traveled approach roadway at all times. The TVMS shall not block the driver’s rear view vision when either in the transport or the deployed position.
104.29.03 Construction
104.29.03 01 Equipment.
Truck. The work vehicle size and the method of attachment shall be as specified in the manufacturer's specifications. All vehicles shall be in accordance with Maryland Motor Vehicle Law. Structural Support. The structural support framework shall allow the system to be assembled into a unit and be mounted on the truck and shall provide the support mechanism between the sign panel assembly, the power supply, and the controller. The framework shall provide sufficient support to prevent damage to any TVMS components when the sign is in the down and locked position during normal highway travel. The sign panel shall be mounted as a permanent fixture of the truck and provide a minimum height of 7 ft from the bottom of the sign to the surface of the roadway when in its operating position. Affixing a trailer mounted unit to a truck is prohibited. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS The deployed structure shall supply adequate support to allow complete sign operation including raising and lowering of the sign panel during sustained wind speeds of 85 mph. The display windows shall be made of impact-resistant clear Lexan or as approved. Sign Panel. Sign panel dimensions shall not exceed 92 in. wide by 54 in. high unless approved. The TVMS shall be capable of displaying three lines of text with the following requirements:
a.Each line of text shall be constructed using a full matrix display. (b) The sign shall be capable of displaying six characters per line. (c) The character height shall be at least 12 in. (d) The sign shall have a pixel arrangement of at least 20 rows by 40 columns, with at least 3 LEDs per pixel. LED Illumination. LED illumination for each matrix element shall have the following characteristics:
a.LED shall meet to the ITE specification for amber color. (b) LED shall utilize A1InGap substrate. (c) Each LED shall produce at least one candela output on center at 25 mA drive current. (d) LED shall provide full illumination within at least a 24 degree cone perpendicular to the sign face.
e.Operating temperature range of the LED shall be -30 F to 125 F. TVMS Unit. Submit a catalog cut and character set for any TVMS approval to the Office of Traffic and Safety, Chief of Traffic Operations. Furnish examples of standard messages to be used on the sign. Lift Mechanism.
a.The lift mechanism shall be capable of being raised and lowered manually. (b) A self-locking mechanism shall be provided to prevent the sign panel from lowering once in the raised position. Electrical Connections and Gauges.
a.All wiring from power sources to TVMS equipment shall use locking cable connectors. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
b.Each sign shall be equipped with an automatic lamp intensity regulator that maintains a constant output with a varying battery voltage.
c.Standard negative ground system shall be tied to the vehicle chassis. Power Supply. The TVMS shall operate from a solar powered electrical system. Sign Controller. The controller shall:
a.Be capable of driving the matrix display panel operating over a -30 F to 125 F range and in a 20 percent to 95 percent noncondensing humidity range.
b.Accommodate 50 preprogrammed, user-defined messages. (c) Be capable of displaying three sequenced messages. On/Off time for each message in a sequence shall be user adjustable at one-tenth of a second increments within a range of 0 second to 5 seconds.
d.Be designed for fail-safe prevention of improper information display in the case of a system malfunction. In the event of a system malfunction, the sign shall display a blank message.
e.Have the capability of retrieving all messages stored in temporary memory.
1.Temporary memory shall be nonvolatile.
2.All messages and programs shall remain resident in the controller’s memory in the event of a power failure.
3.Have an RS-232 port to facilitate connection of an external communication device.
f.Monitor and display the battery output voltage and solar array activities (charging and discharging) and blank the sign when the battery output voltage drops below the manufacturer’s recommended output level.
g.Be capable of monitoring and displaying the status of the photocell, adjust the sign illumination to match the ambient light conditions, and have at least nine levels of dimming from 10 percent to 100 percent brightness.
h.Be contained in a sheet metal or high density polyethylene (HDPE), weatherproof cabinet located on the controller housing, and insulated to protect against excessive vibration and temperature.
1.The cabinet shall have a lockable door latch.
104.29 Truck Mounted Variable Message Sign (Tvms)
2.The keyboard/input device storage location shall be provided inside the cabinet. Character Set Software. The character set software shall:
a.Have all the standard ASCII characters and symbols.
b.Provide left and right arrows. (c) Have all alphanumeric entries performed with a keyboard or keypad that causes the same character to be displayed on the matrix. Arrow symbols shall be generated via a cursor pad on the keyboard or keypad.
d.Have messages default to self-centering display with the ability to left or right justify.
104.29.03 02 Operation. Set up and operate the TVMS 24 hours in advance of actual use to
ensure that each unit is functioning properly and approved. Variable Message Sign Mode. Use the TVMS in variable message sign mode on roadways where the posted speed limit is less than or equal to 40 mph. The TVMS is intended for mobile operations. If used for stationary construction or maintenance operations, do not leave the TVMS in place for more than eight consecutive hours. Arrow Panel Mode. The TVMS may be used in lieu of a Type C arrow panel on any roadway as long as the TVMS is capable of displaying a left arrow, right arrow, double arrow, and a four- corner caution mode and as specified in 104.07.03. Lights with a preflash option of white strobe or pulsed lighting shall not be displayed. Use the TVMS only as a supplement to other required traffic control devices. When closing a through travel lane on a multilane roadway, use the “Arrow” mode only. Only one TVMS in the “Arrow” mode shall be used for each stationary lane closure. Moving work operations may utilize one or more TVMS for a single lane closure.
a.Ensure that the placement does not cause driver confusion near ramps, median crossovers, and side road intersections.
b.For stationary lane closures, place the TVMS on the shoulder at the beginning of the taper (nearest to oncoming traffic). Where there are narrow or no existing shoulders adjacent to the closed lane behind the channelizing devices, place the TVMS as near to the beginning of the taper as possible.
c.For moving maintenance type activities along multilane highways where a lane is closed, place the TVMS at the rear of the activity in the closed lane on a vehicle separate from the maintenance vehicle itself. For paint striping activities, additional vehicles with TVMS or arrow panels in the arrow mode may be required to supplement the work operation. TVMS shall always remain upstream of the maintenance vehicles where 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.29 Truck Mounted Variable Message Sign (Tvms)
adequate recognition distance is available. The vehicle carrying the TVMS shall be equipped with signing and lighting as required by the standard TCPs.
d.TVMS shall only display the “Caution” mode for a lane closure on a two-lane, two- way roadway, or for a shoulder closure on any roadway. The “Caution” mode on a TVMS shall show displays of circular appearance in each of the four corners of the TVMS. The circle diameters shall range from 9.5 in. to 11 in. and utilize approximately 30 pixels. The circles shall be offset from the left and right edge between 3 in. and 6 in. and from the top and bottom edge between 1.5 in. and 3 in. The vertical spacing between the centers of the circles shall range from 2.5 to 3 times the diameter of the circles. The horizontal spacing between the centers of the circles shall range from 1.75 to 2 times the vertical spacing. Install the TVMS as specified. The TVMS shall be designed so that it supplies a minimum visibility and legibility distance of 900 ft. Ensure that the TVMS is level and that the sign face is not obscured by highway alignment or glare from either sunlight or vehicle headlights.
104.29.04 Measurement and Payment
Truck Mounted Variable Message Sign will be measured and paid for at the Contract price per unit day. A unit day will consist of any approved usage within a work shift, regardless of start time or whether the shift runs into another calendar day. Each truck mounted variable message sign will be paid for only once per unit day, regardless of how many times it may be relocated. When a truck mounted variable message sign is used for part of a day, it will be measured and paid for as a unit day. When operations require continuous 24 hour use of a truck mounted variable message sign, the unit day will be measured as 24 hour periods from start to finish. The payment will be full compensation for the vehicle, setup and maintenance of computer programs, changing messages, and for all material, labor, equipment, tools, and incidentals necessary to complete the work. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.30 Portable Traffic Signal (Pts)
2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS CATEGORY 100 PRELIMINARY SECTION 104.30 — PORTABLE TRAFFIC SIGNAL (PTS)
104.30.01 Description
Furnish, install, and maintain a portable, self-contained, trailer mounted traffic signal for maintenance of traffic operations as specified in the Contract Documents or as directed by the Engineer.
104.30.02 Materials
Portable Traffic Signal (PTS) As Approved by Office of Traffic and Safety
104.30.03 Construction
Place PTS trailers in the closed lane during alternating one-lane, two-way traffic operations, without intruding into the travel lane, or as directed by the Engineer. The Contractor is responsible for all setup procedures necessary for the PTS including setting up the trailers, setting up and testing the remote monitoring system notification, aiming signal heads, interconnecting the signal controllers, aiming, and adjusting vehicle detection units, and installing the timing provided by the Office of Traffic & Safety.
104.30.03 01 Equipment. Each PTS shall be a trailer mounted unit. A PTS system shall consist of two or more trailers. Each
unit shall be self-contained battery powered with solar assist, consist of two signal heads per trailer, and a solid state signal controller. One signal head should be mounted on an overhead mast arm capable of extending over the travel lane. The other signal head shall be mounted on a vertical upright. The PTS system shall have non-intrusive vehicle detectors and each PTS must be interconnected to each other at all times with a twisted pair shielded cable or wireless radio link with sufficient range, as specified in the Contract Documents or as directed. Trailer. The trailer shall conform to Maryland Motor Vehicle Law governing trailers. Support Structure. The PTS trailer shall be capable of accommodating a vertical upright and a horizontal mast arm. The trailer and all mounted equipment shall be structurally adequate for unlimited, normal operation in wind velocities typically encountered on the roadway (gusts of 80 MPH). No additional ballast shall be used to achieve the structural stability required for normal operation. Additional ballast includes but is not limited to, sandbags, concrete/cement blocks and
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 221–225 of 1,113.