Traffic Control During Construction

Traffic control for highway ‑rail crossing construction is very similar to traffic control for highway construction. The major difference is that the work area is in joint-use ROW, and the possibility of conflict exists between rail and highway traffic as well as in construction operations. Construction areas can present unexpected or unusual situations to the motorist as far as traffic operations are concerned. Because of this, special care should be taken in applying traffic control techniques in these areas. Temporary Traffic Control (TTC), as found in Part 6 of the MUTCD, discusses the importance of each mode of transportation and road user in relation to highway construction, utility work, maintenance operations, and the management of traffic incidents. Additional information regarding the requirement for a Traffic Management Plan for significant projects and TTC for non ‑significant projects can be found in Subpart J and K of the Work Zone Management Program’s Work Zone Safety and Mobility Rule (Subpart J) and the Temporary Traffic Control Devices Rule (Subpart K) (website: https://ops.fhwa.dot.gov/wz/resources/policy.htm). Traffic safety in construction zones should be an integral and high ‑priority element of every project, from planning through design and construction. The TTC planning is important to provide continuity for the movements of all modes and highway-users during periods when the normal function of the roadway is suspended. Providing for the safe and effective movement of highway-users as they travel through or around a TTC zone, while also focusing for the safety of workers and first responders, is a key function of TTC. The basic safety principles governing the design of crossings should also govern the design of construction and maintenance sites. The goal should be to route traffic through such areas with geometries and traffic control devices comparable, as possible, to those for normal crossing situations. A traffic control plan in detail appropriate to the complexity of the work project should be prepared and understood by all responsible parties before the site is occupied. If traffic flow will be impacted or the roadway will be closed, advance notification to the public should be provided to the public through news releases, social media, and other means as needed. Information on the length and times of closure or impact as well as established detour information should also be provided. 145When planning construction or maintenance work at highway-rail crossings, proper coordination with the railroad is essential. The safety of road users, highway and railroad work crews, and train crews can best be provided through the development of a work plan to meet the needs of rail and highway traffic.

Traffic Control Zones

When traffic is affected by construction, maintenance, utility, or similar operations, traffic control is needed to safely guide and protect road users and workers in a traffic control zone. The traffic control zone is the distance between the first advance warning sign and the point beyond the work area where traffic is no longer affected. Temporary traffic control should be developed and/or reviewed by the road authority, not the railroad.

Traffic Control Devices

Signs. Regulatory and warning signs are used in construction work areas. Regulatory signs impose legal restrictions and may not be used without permission from the authority having jurisdiction over the highway. Warning signs are used to give notice of conditions that are potentially hazardous to traffic. Delineators. Delineators are reflective units with a minimum dimension of approximately 3 inches. Delineators should not be used alone as channelizing devices in work zones but may be used to supplement these channelizing devices in outlining the correct vehicle path. They are not to be used as a warning device. To be effective, several delineators need to be seen at the same time. The color of the delineator should be the same as the pavement marking that it supplements. Pavement markings. Pavement markings, in conjunction with delineators, outline the vehicular path and, thus, guide the motorist through the construction area. Pavement markings include longitudinal markings such as center lines, edge lines and lane lines, as well as word, symbol and arrow markings. Channelizing devices. Channelizing devices consist of cones, tubular markers, vertical panels, drums, barricades, and barriers (refer to MUTCD Figure 6F-7). These types of devices are used to maintain traffic through work zones. Lighting devices. Three types of warning lights may be used in construction areas. Flashing- lights are appropriate for use on a channelizing device to warn of an isolated hazard at night or call attention to warning signs at night. High-intensity lights are appropriate to use on advance warning lights during day and night. Steady-burn lights are appropriate for use on a series of channelizing devices or on barriers that either form the taper to close a lane or shoulder, or keep a section of lane or shoulder closed, and are also appropriate on the channelizing devices alongside the work area at night. Flagging. Flagging of the highway should be used only when required to control traffic or when all other methods of traffic control are inadequate to warn and direct drivers. The procedures for flagging traffic are contained in MUTCD Chapter 6E. It should be noted that construction activity within the railroad right ‑of‑way will require railroad flagging. The industry standard 146is that the operating railroad will provide flaggers with the appropriate safety certifications. Availability of railroad flaggers is limited and construction activities need to be carefully coordinated with the railroad which controls the scheduling of qualified flaggers.

Typical Applications

Practitioners should refer to Part 6 of the MUTCD for various “Typical Applications” of temporary traffic control, some of which could be used where a construction detour near a crossing is required. Two examples showing applications of traffic control devices in crossing work zones are shown in Figure 62 and Figure 63 for work in the vicinity of a crossing and where there is work on a side road with a crossing, respectively. The dimensions shown in these figures may be adjusted to fit field conditions in accordance with the guidelines presented in MUTCD and the Traffic Control Devices Handbook. When numerical distances are shown for sign spacing, the distances are intended for rural areas and urban areas with a posted speed limit of 45 mph or more. For urban areas with a posted speed of 45 mph or less, the sign spacing should be in conformance with Table 9. Table 9. Recommended Advance Warning Sign Minimum Spacing

Road TypeDistance Between Signsb

A B C

Urban (low speed)a100 feet 100 feet 100 feet

Urban (high speed)a350 feet 350 feet 350 feet

Rural 500 feet 500 feet 500 feet

Expressway/Freeway 1,000 feet 1,500 feet 2,640 feet

a Speed category to be determined by the highway agency . b The column headings A, B, and C are the dimensions shown in Figures 6H-1 through 6H-46 (MUTCD). The A dimension is the distance from the transition or point of restriction to the first sign. The B dimension is the distance between the first and second signs. The C dimension is the distance between the second and third signs. (The “first sign” is the sign in a three-sign series that is closest to the TTC zone. The “third sign” is the sign that is furthest upstream from the TTC zone.) Source: Manual on Uniform Traffic Control Devices, 2009 Edition, Washington, DC, FHWA, 2009. Signs with specific distances shown should not be used if the actual distance varies significantly from that shown. The word message “Ahead” should be used in urban areas and in other areas where a specific distance is not applicable. Standard crossing pavement markings are not shown in the figures for clarity but should be utilized where appropriate. All applicable requirements for traffic control in work areas set forth in MUTCD should apply to construction and maintenance of crossings. Additional traffic control devices other than those shown in the figures should be provided when highway and traffic conditions warrant. These devices should conform to the requirements of MUTCD. All traffic control devices that are not applicable at any specific time should be covered, removed, or turned to not be visible to the motorist. Figure 62. Work in the Vicinity of a Crossing (TA-46) Source: Manual on Uniform Traffic Control Devices, 2009 Edition, Washington, DC, FHWA, 2009. work Figure 63. Crossing Work Activities, Closure of Side Road Crossing Source: Railroad Highway Grade Crossing Handbook, Revised Second Edition.