104.24 Workers Present Trailer (Wpt)
CATEGORY 100 PRELIMINARY SECTION 104.24 — WORKERS PRESENT TRAILER (WPT)
104.24.01 Description
A Workers Present Trailer (WPT) is designed to enhance motorists’ situational awareness when entering a work zone where workers are present. When activated, a WPT will display alternating flashing YELLOW signal heads (beacons). Furnish, install, operate, and relocate a portable, self-contained, WPT with flashing beacons and ‘Work Zone - Fines Higher When Flashing’ (R2-6(5)) sign as specified or as directed.
104.24.02 Materials
Workers Present Trailer QPL Reflectorization 950.03 Sign Material 950.08 Traffic Signal Heads 950.15 Each WPT unit shall include the trailer, structural support system, sign panel assembly, lift mechanism, power supplies, trailer mounted controller, flashing beacons, communications, and ancillary equipment. All materials for the WPT shall be like new, corrosion resistant, and unaffected by water spray, salt, oil, gasoline, and all other contaminants in the quantities typically found along the edge of a traveled roadway. Construction, materials, and operation shall be in accordance with NFPA, UL, and NEC. The WPT trailer shall be painted orange and shall comply with Maryland Motor Vehicle Law. 104.24.02.01 Equipment.
a.Trailer. In accordance with Maryland Motor Vehicle Law governing trailers. (b) Structural Support. Refer to 104.19.
c.Sign Panel.
1.‘Work Zone - Fines Higher When Flashing’ (R2-6(5)) sign shall be attached to the WPT. The sign dimension shall be 48 in. wide by 60 in. high. The top portion of the sign face shall have a fluorescent orange background with black letters and border, and the lower portion of the sign face shall have a white background with black letters and border, and the sign face shall be 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.24 Workers Present Trailer (Wpt)
reflectorized as specified in 950.03. The sign shall be mounted to the WPT at a minimum mounting height of 5 ft measured from the bottom of the sign to the road surface and in a manner that allows for easy removal when necessary for maintenance. The minimum mounting height shall be increased to 7 ft if the trailer is placed in business, commercial, or residential areas.
d.Lift Mechanism.
1.The lift mechanism shall be installed such that the sign panel can be raised and lowered manually.
2.A corrosion resistant safety bolt or pin shall be provided to prevent the sign panel from lowering once in the raised position. A self-locking mechanism shall be incorporated into the safety bolt or pin to prevent it from being inadvertently dislodged.
e.Electrical Connections and Gauges.
1.All wiring from power sources to WPT equipment shall use locking cable connectors.
2.Volt and amp gauges shall be provided for DC.
3.Standard negative ground system shall be tied to the sign chassis.
f.Power Supply. The WPT shall operate from a solar powered electrical system consisting of battery power and solar array panels. The electrical system shall be capable of supporting continuous operation of the system for 21 consecutive days without an auxiliary charge and be capable of being charged by a generator or other commercially available power source in case of malfunction, damage, or failure of the primary solar powered electrical system.
g.Controller Requirements. The controller shall be capable of the following.
1.Being controlled locally at the unit and remotely via a remote on/off via cellular connection and an internet accessible interface.
2.Driving a flashing beacon operating over a -30 F to 125 F range and in a 20 percent to 95 percent noncondensing humidity range.
3.Monitoring and displaying the battery output voltage and solar array actives (charging and discharging).
4.Being 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. The cabinet shall be equipped 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.24 Workers Present Trailer (Wpt)
with a lockable door with hasp/lock setup installed in a manner to maximize its effectiveness in stopping unauthorized access to the beacon controls. Other physical locking devices may be approved by the Engineer.
h.Yellow Lens Requirements.
1.The WPT unit shall have two 12 in. circular signal heads mounted on the front side of the WPT facing approaching traffic. Each signal head shall have one circular yellow lens. The indications shall illuminate in an alternating flashing pattern when activated and shall be mounted in one of the following ways:
i.Mounted Top/Bottom with one signal head placed above and below the R2- 6(5) sign. A signal head mounted at the bottom of the R2-6(5) sign shall be mounted a minimum height of 5 ft measured from the bottom of the signal head to the road surface. (ii) Mounted Top Only with both signal heads placed at the same height and symmetrically centered above the R2-6(5) sign. (iii) Mounted Left and Right Side with both signal heads placed at the same height on the left and right side of the R2-6(5) sign. Signal heads mounted on the left and right side of the sign shall be mounted at a minimum height of 7 ft measured from the bottom of the signal heads to the road surface.
2.Signal heads shall be as specified in 950.15 and shall meet the physical display and operational requirements of flashing beacons according to Part IV of the Maryland Manual on Uniform Traffic Control Devices (MdMUTCD). Each signal head shall be aluminum or polycarbonate having one 12 in. YELLOW LED indication. The signal head shall be equipped with a visor which extends beyond the signal head a minimum of 10 in. All signal housings shall be black or yellow.
i.Beacon Status Indicator. WPT shall be supplemented with one 4 in. minimum diameter yellow LED warning light mounted on the back of the WPT. The warning light shall be mounted a minimum of 7 ft measured from the bottom of the warning light to the road surface and shall not be visible to motorists approaching the WPT from the front. The warning light shall illuminate in a flashing pattern when the front-facing signal heads are activated, and shall not illuminate when the front-facing signal heads are deactivated. The warning light will enable workers downstream in the work zone to confirm the WPT system is operational.
j.Communications. The WPT systems shall be equipped with a vendor-provided cellular and modem communication system.
k.Monitoring System Requirements. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.24 Workers Present Trailer (Wpt)
1.GPS shall be used to monitor trailer location.
2.Be capable of reporting sign panel orientation. (3) Be capable of reporting the current time and date, flashing beacon operating status, battery voltage, available solar power, trailer location in latitude/longitude, sign panel heading, and system malfunction.
4.Be capable of configuring customizable alerts and immediately communicating alerts and device malfunction via electronic notification (e.g. text or email) to responsible individuals.
5.Be capable of providing real-time information automatically to the Administration or its designee with connected capabilities. The connected capabilities shall allow the WPT to transfer reportable data over a cloud network without human interaction using communication technology. The WPT shall provide a cellular network router used for remote communications and real-time GPS tracking to inform remote system users of the reportable data.
6.Provide electronic communication between the WPT, WPT central server, and the Administration or its designee following the Administration’s protocol.
l.Default Requirements. WPT systems shall revert to a non-flashing mode upon system malfunction. Upon system malfunction, the WPT system shall immediately contact a minimum of three responsible individuals via the remote monitoring system described in the Operating System Requirements section. The WPT system repairs shall be the responsibility of the contractor and rendered in a manner that will return the WPT to full operation condition in the most expeditious manner.
m.Operating System Requirements.
1.The flashing beacon controller shall be enclosed in a cabinet mounted on each trailer.
2.Be controlled with a Graphical User Interface for programming on-site.
3.A web interface shall be used for remote programming, monitoring, and reporting.
4.Be capable of scheduling unique and reoccurring schedules. (5) Be capable of tracking and recording accurate date/time, location, sign panel orientation, WPT identification number, and project number. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.24 Workers Present Trailer (Wpt)
6.The operating system shall be equipped with diagnostic capabilities in the event of a system malfunction.
7.The system shall have the capability of identifying the malfunction in a manner that will expedite the return to full operational mode.
n.Logging/Reporting. Flashing beacons on the WPT shall be activated when workers are present in the work zone and deactivated when workers are not present.
1.The operating system shall have an integrated mechanism capable of logging date and time information when the flashing beacons are activated and deactivated.
2.Be capable of locally storing 30 days of activation/deactivation records with a time and date stamp, GPS location, sign panel orientation, WPT identification number, Administration project number, and have sufficient memory to store at least 100,000 records in the cloud.
3.Be capable of remote access to activate/deactivate, retrieve records, and to download records in a printable format.
4.Be capable of transmitting real-time information of device activation/deactivation and updated every 15 minutes. Information shall be retained for one year following project completion date and be stored in the cloud and available to the Administration upon request.
5.Reports indicating the date and time flashing beacons are activated and deactivated, GPS location, sign panel orientation, WPT identification number, shall be provided daily to the Office of Traffic and Safety and its designated representative.
104.24.03 Construction
Furnish, install and test the WPT on the project site 24 hours in advance of actual use to ensure that each unit is functioning properly. Place the WPT unit as shown in the Contract Documents or as directed and aim WPT at approaching traffic to ensure sign panel and flashing beacons are visible and legible for a distance of 900 ft from any point along the travel approach roadway. Ensure the WPT is level and that the sign face is not obscured by highway alignment or glare from either sunlight or vehicle headlights. Install temporary concrete traffic barrier or drums around the WPT according to the Book of Standards and the Contract Documents. Activate the WPT when workers are present in the work zone. Deactivate the WPT when workers are not present. Ensure that the WPT is operational for duration while workers are present in the work zone. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.24 Workers Present Trailer (Wpt)
The WPT shall be able to withstand wind of 80 mph.
104.24.04 Measurement and Payment
104.24.04 01 Workers Present Trailer will be measured and paid for at the Contract price per unit
day for each Workers Present Trailer unit. 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 Workers Present Trailer will be paid for only once per unit day, regardless of how many times it is relocated. When a Workers Present Trailer 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 Workers Present Trailer, the unit day will be measured as 24 hour periods from start to finish. The payment will be full compensation for the Workers Present Trailer and for all material, labor, equipment, tools and incidentals necessary to furnish, install, operate, and maintain the Workers Present Trailer at the site as required and at any relocated site as specified or as directed.
104.24.04 02 Workers Present Trailer related sign R2-6(5) will not be measured but the cost will
be incidental to the Contract unit price for Workers Present Trailer.
104.24.04 03 The signal heads/beacons will not be measured but the cost will be incidental to the
Contract unit price for the Workers Present Trailer. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
104.26 Removable Rumble Strips
CATEGORY 100 PRELIMINARY SECTION 104.26 — REMOVABLE RUMBLE STRIPS
104.26.01 Description
Furnish, install, maintain, and remove removable rumble strips.
104.26.02 Materials
Removable Rumble Strips QPL Rumble strips shall be white in color, 4 in. wide, and 0.250 in. thick.
104.26.03 Construction
104.26.03 01 Quality Assurance/Quality Control. Perform quality control testing using
technicians certified by the Administration.
104.26.03 02 Warranty Period. Maintain the rumble strips and repair defects for a period of
180 days from the date of application. Replace as necessary within this period as directed at no additional cost to the Administration. Refer to GP-5.11. At least 90 percent of the total number of rumble strips in any lane shall be free from signs of failure due to blistering, excessive cracking, discoloration, smearing or spreading under heat, chipping, spalling, or poor adhesion to the pavement. Replace rumble strips showing wear or a thickness less than 0.20 in.
104.26.03 03 Application and Removal. The pavement surfaces shall be completely dry and
free of oil, grease, sand, dirt, dust, loose aggregate, soil, salt, and other contaminants. Apply the rumble strips in accordance with the manufacturer’s recommendations and the Contract Documents. Place perpendicular to the flow of traffic and located as specified. Space the strips between 4 ft and 10 ft on center, with a pattern of at least 10 but not more than 12 strips per set. Decrease the spacing within each set as motorists approach the work zone. The spacing between the sets shall be as specified. Do not place on sharp horizontal or vertical curves. Use in conjunction with other traffic control devices or visual cues that will assist drivers in identifying the appropriate action to take. 2025 STANDARD SPECIFICATIONS FOR CONSTRUCTION AND MATERIALS
Source: Maryland Standard Specifications for Construction and Materials, 2025 Edition. Pages 207–212 of 1,113.