Especially around this time of the year, we hear the advice, “Drive safely,” all the time. It’s obviously good advice, but safety is not just up to the driver, it’s also a matter of how the road is designed and maintained. Being able to drive safely is a particularly critical issue when it comes to road construction activity. In this edition of the RoadReady newsletter, we’ll look at some examples of best practices to consider in planning traffic control strategies for construction work zones.
Traffic Control Plans
Any road construction project should have a traffic control plan that addresses how vehicles will move safely through the work zone. As part of traffic control design, one concept that is often helpful is to address two distinct areas, site traffic control and internal traffic control. While site traffic control deals with the safety of the general public moving through the work zone, internal traffic control covers safety issues for construction workers and vehicles on the jobsite.
Site Traffic Control
Site traffic control involves strategies designed to move vehicles safely through the work zone so that they do not interfere with construction activity. This includes essential aspects such as required lane closures along with temporary signs and pavement markings. In addition to these core elements, the following are some of the strategies that may be useful to enhance traffic safety during a construction project.
Incident management service patrols. Many agencies dedicate tow trucks and operators to long-term highway work zones or include this as a requirement in their contracts. Having emergency assistance vehicles available to deal with stalled vehicles quickly helps restore traffic flow through the work zone and keeps small problems (a flat tire or running out of gas) from turning into big ones (collisions and injuries). Helping stranded motorists can also benefit the agency and the contractor by improving their public image.
Passive radar with portable changeable message signs. Consideration should always be given to the appropriate speed limit to implement in a construction work zone. Whether or not this is a reduction from the normal roadway speed limit, installing an unmanned radar gun with a display readout comparing a vehicle’s current speed with the work zone speed limit can help improve driver behavior. These are generally positioned in advance of locations where the work zone changes the actual traffic pattern as a warning device and to make drivers more alert, particularly if they are not familiar with the area.
Selective closure of on-ramps on highways. Especially on high-volume freeways, closing some ramps may be desirable to improve safety in construction work zones, depending on traffic patterns and the feasibility of directing surface street traffic to alternative entrances. Closing ramps reduces traffic weaving and allows vehicles to move through the work zone with less congestion.
Restrictions on the length of active work zones. On projects that cover an extensive stretch of roadway, rather than opening up the entire project area to construction, limit road closures to a specific length, such as 1-2 miles. This can reduce travel delays because the road closure is not as extensive, and also helps spread the burden for drivers who use different portions of the roadway. Strong outreach efforts and a well-designed traffic control plan should be included to ensure that the safety benefits are realized and the traveling public understands what is happening, rather than being confused by shifting work zone locations.
Temporary rumble strips. Rumble strips can be created using portable plastic mats or thick tape designed for temporary installation. When placed across travel lanes, the strips alert drivers to slow down and anticipate potential obstructions or changes in the traffic pattern. The rumble strips can be installed at the approaches to the construction area or other suitable locations within the work zone, such as near a temporary traffic signal.
Internal Traffic Control
Internal traffic control is focused on construction vehicles and equipment within the work zone. Especially on large, complex job sites, an internal traffic control plan is needed to make sure that construction activity moves in a safe and predictable manner. The following are some important strategies for internal traffic control in the work zone.
Designated entry and exit points. The work zone should be designed so that construction vehicles and equipment can safely enter and exit the construction area. Locations for entry and exit should be selected with consideration for the roadway geometry, including the need to accelerate to or decelerate from general traffic speeds. The turning radius for trucks also needs to be considered.
Separate incompatible activities. Traffic control devices such as cones, drums, and barriers can be used within the construction area as well as to separate the work zone from general traffic. Buffer zones should be established to prevent potential conflicting movements of workers and equipment. Areas for material storage and equipment servicing may need to be delineated.
Dedicated parking and holding areas. Trucks and other material transports may be looking to simply get in, deliver their loads, and get out again, but sometimes the timing of operations requires drivers to wait. At the same time, other vehicles may need to be present at the site for longer periods. Depending on where they are parked, they could be a hazard to construction activity or to general traffic if left unattended. Designating secure, identifiable areas within the work zone as holding areas or for construction parking will help keep everyone safer.
Fundamentally, work zone traffic control involves putting safety first and making it a shared responsibility. Drivers, equipment operators, workers, and everyone around a project should all be looking out for each other as well as their own safety. No matter where you may be working or traveling, we at Pavia Systems wish you a safe and happy holidays!
Federal Highway Administration, Manual on Uniform Traffic Control Devices: http://mutcd.fhwa.dot.gov/
Federal Highway Administration, Work Zone Best Practices Guidebook: http://www.ops.fhwa.dot.gov/wz/practices/best/bestpractices.htm