Work Zone Safety FAQs

Cones, barrels, and barriers

1.  Why do you close off a long stretch of roadway when work is only being done in a short section?

A.  There are many reasons why a given length of roadway is closed, but the main reason is that work is being conducted to maximize productivity even though it may appear to the driver that little or no work is in progress at any given time. Remember, the work zone is usually observed by the driver for a very short period of time. Roadway work is very dynamic with several ongoing work operations synchronized to result in a finished product. This is usually true for both long and short duration work. Also, it is generally more efficient and safer to implement the traffic control for the entire length of the work zone. Closure of longer sections also provides consistency throughout the project to minimize disruptions or changes to driver expectations as would be the case with a constantly changing work zone.

Common work operations that are not always observed:

  • Survey and layout work including staking, measurements and stationing
  • Preparation work, such as sweeping and cleanup
  • Equipment and material mobilization and stockpiling
  • Preliminary repair work operations
  • Utility relocations
  • Related individual work operations done in advance of the main work effort
  • Punch list items to be completed near the end of the project and prior to release of the contractor

2.  Why do you close off two lanes when work is only being done in one?

A.  In many cases, it is not feasible or safe to conduct work operations within the limits of a single lane due to the activity performed, equipment constraints or ingress/egress. Maintaining traffic directly adjacent to a work operation, separated only by a lane stripe is extremely hazardous for both drivers and workers. Long term projects may utilize temporary concrete barrier to separate traffic from the work zone rather than close the adjacent lane. Project specific Traffic Management Plans (TMPs) are developed to identify any unique elements or issues related to a particular project. The TMP is developed during the design process based on site specific details and challenges including impacted roadways adjacent to the project, local residents, businesses and other elements specific to a project. Every effort is made to provide safe and efficient movement of vehicles, pedestrians and bicycles through a work zone while maintaining worker safety and minimizing traffic impacts as much as possible. Practice is to close the minimum number of lanes to safely and effectively complete the work.

FYI ... the length of a work zone (freeway lane closures) has a minimal effect on traffic delay ... most of the delay is generated at the actual lane closure taper. (A taper is a series of traffic control devices that move traffic out of or back into its normal path.)

3.  Why are long lane closure tapers needed?

A.  Lane closure tapers are designed to accommodate safe and efficient merging. The major consideration is traffic speed - the higher the speed the longer the taper. A common freeway lane closure would use a minimum 720’ taper for 60 MPH posted speed limit.

Construction signs

4. Why do you post “Construction Ahead” signs when no work is going on?

A. TDOT is legally obligated to post “Road Work Ahead” or other warning signs as needed at work zones for any activities, disruptions or changes to normal traffic patterns. Even though there may be no obvious work activity, there probably is some minor work underway or the condition of the roadway may have been changed due to previous work. We want to ensure that drivers are aware that they are in a work zone and are alert to any work zone conditions (even minor conditions) that might not be present under normal operational conditions.

5. Why are some work zones in place for months and some only a single day?

A. The type of work performed will determine how long the work zone remains in place. Work zones are set up in the same manner whether in place for one hour or over several days. There are several classifications for work zones with the most common known as one of the following: Long term stationary, short term stationary or Mobile work zones. Long term stationary work zones occupy an area for periods longer than 3 days. Typically, these work zones are associated with road widening, paving, bridge replacement or other similar project work that is usually conducted through managed contracts over longer periods of time. Short term stationary activities generally occur over the period of one work day and may only last up to one hour for any given location. The location of short term work activities may change on a daily basis. Short term stationary work is most often associated with roadway maintenance activities including ditch work, patch paving and roadway repairs, sign replacement and other activities conducted to maintain the roadway system. Short term can also include managed contract work activities including guardrail repair and replacement. Mobile work activities are conducted with continuous movement in one direction. Mobile work zones can be associated with either managed contracts or in-house maintenance activities. Common examples of mobile activities include roadway striping, herbicide application, mowing operations and litter pick up. Regardless of the duration or type of activity conducted, the messages conveyed to motorists should look similar and consistent in the setup of traffic control devices to minimize changes to driver expectations.

6. Why don’t you post signs far enough ahead of the work area so that we can take a detour/avoid a backup?

This is usually considered as part of the planning and design for work zones and is included during the Traffic Management Plan (TMP) development process. Unfortunately, the length of a backup can be difficult if not impossible to predict on any given day. TDOT has utilized Intelligent Transportation System (ITS) tools such as traffic flow detectors, cameras and portable changeable message signs (PCMS) in response to backups in an effort to provide alternate routing choices to motorists. Permanent variable message signs (VMS) are also used if their location relative to the work zone and alternate route is contained within this communication network. Technology is becoming available to allow us to monitor work zone backups and remotely send real time messages to PCMS’s strategically located in advance of alternate routes. Smart Work Zones are being developed to communicate relevant information to drivers while travelling through a work zone. Smart Work Zones include speed indicators, monitoring for slow or stopped conditions and allow drivers to then be alerted of changing conditions with the PCMs.

7. I passed a lane-closed sign, everyone was moving over, and there was no one working – what’s up with that?

A. This does happen and is usually due to setting up or taking down work zone signs and devices. Many work zones can be labor intensive to install and remove and can take 1 or 2 hours depending on the size and complexity. If a driver happens to be traveling through a work zone during these periods, the work zone may not be fully operational. Occasionally, a sign may be inadvertently left in place when it is not needed, and we try to respond as soon as possible if this happens. This may also be a nighttime project where the majority of work activities occur during the nighttime hours while traffic volumes are lower.

8. What are the different kinds of signs you use in work zones?

A. Work zones are commonly identified by orange warning signs with black lettering. Many work zones also use a full array of standard road signs as listed below. Remember all rules of the road apply in work zones, including compliance to the posted signs.

  • Orange work zone warning signs
  • Orange safe speed advisory signs (curves, rough roadway, etc.)
  • Black on white regulatory signs (i.e. Speed Limit, Lane Control, etc.)
  • White on red regulatory signs (i.e. Stop and Yield signs)
  • Portable Changeable Message Signs (PCMS)
  • Variable Message Signs, permanent (VMS)
  • Temporary guide and directional signing (green or orange)
  • Road Detour/Closed signs
  • Barrels, cones and barriers to guide motorists through the work zone

Night work

9. Why isn’t all construction done at night and how is it decided when it is appropriate?

A. Quite a bit of construction work is done at night in an effort to avoid the higher volume daytime hours and associated traffic delays.  Not all construction work is compatible with night work and some construction work cannot physically be completed at night and reopened the following day. Often times, daytime work zones are either longer in duration in that it covers multiple days and nights to complete or short-term stationary work that occupies a location for no more than one day. Short-term projects are typically associated with roadway maintenance activities. If traffic can be maintained at a reasonable level, we would prefer to conduct work during the day for the following reasons:

  • Maintenance activities including roadway patching, ditch work, driveway repairs and bridge drain cleaning requires employees to work in close proximity to residences and meet with the public to discuss any issues with rights-of-way adjacent to their homes.
  • Due to site specific and typically small quantities utilized by maintenance forces, on a daily basis, as compared to a contracted project, suppliers will open during normal daylight hours only. Therefore, some products used to repair roads are only available during normal business hours.
  • Roadway widening projects that are more long-term in nature utilize a more permanent setup of the work zone. This work zone will remain in place for the duration of the project, other than any planned phasing changes, and the contract price for daytime work is usually better than for nighttime work.
  • Mobile operations, typically associated with litter pick up, roadway striping, herbicide application and mowing operations are all completed more efficiently during daytime hours. Some activities are temperature dependent (i.e. striping and herbicide application) and others are better due to safety and visibility of equipment workers and activity (i.e. litter more visible and obstacles more visible to mowing operations).
  • Production and quality can suffer to some extent because of the difficulty of working under low light and portable light conditions.
  • Night work generally is more expensive due to less production and increased traffic control, lighting and protective measures.
  • Some projects have very restrictive noise ordinances which limit work hours or require additional noise reduction measures.

This is a complex issue and the above information does not totally capture all the elements. We will continue to rely on night work in many of our urban and other high volume work locations simply because the traffic impacts of daytime work would be unacceptable.

 Driving tips

10. What is the proper way to merge when approaching a freeway construction zone?

A. The key issue here is courtesy. Safe and efficient movement of traffic through the merging area approaching a work zone lane closure depends on the merging drivers’ ability to plan ahead, adjust speed and merge into a safe gap between vehicles in the open lane. Merging is much easier and safer when all drivers act in a courteous manner and work together. Legally, the burden is placed on the merging driver to merge in a safe manner.

11. When should I move over when there is a lane closed ahead?

A. Start planning ahead as soon as you can determine which lane is closed. There is no need to abruptly change lanes or merge into the open lane far in advance of the lane closure. Start looking for a safe gap between vehicles in the open lane and merge into that gap in a smooth manner. It is legal to merge into the open lane right up to the actual lane closure taper of devices, but it is recommended to give yourself some additional space and merge somewhat sooner. This will allow a margin of safety in the event that you may not be able to merge as soon as expected.

12. What’s the best thing to do if my vehicle breaks down in a construction zone?

A. Don’t panic, usually help will be on the way soon. Stay in your vehicle if you are in a traffic lane, turn on the vehicle flashing hazard lights and call 911 if you have a cell phone. At the first indication of a problem with your vehicle, drive to a shoulder or off-ramp, if at all possible. If it is safe to get out of your vehicle, raise the hood, call and/or wait for help.

13. What should I do if I get in an accident in a work area?

A. An accident can be a traumatic event even without serious injuries, but remain as calm as possible and stay in your car. If it is possible to move your car out of the traffic lane to a shoulder or other safe area, turn on the flashing hazard lights and do so. Call 911 (Nashville 615-862-8600 for non-life threatening emergencies) if you have a cell phone and/or wait for help. Help should arrive soon.

FYI ... if your vehicle becomes disabled or damaged in a work zone, be extremely cautious if you exit the vehicle even if you are on the roadway shoulder. You may be exposed to high speed traffic hazards, as well as potential hazards within the work zone that are not intended for pedestrians, such as;

  • Shoulder drop-offs or other unprotected drops (Be extremely cautious around barriers, there may be nothing to support you on the other side).
  • Rough walking surface, repair areas, etc.
  • If you are on a section of elevated roadway or bridge, do not cross over any protective barriers, there is probably nothing to prevent you from falling on the other side.


14. Why do you need so many vehicles, when only one or two people are doing work?

A. Many roadway work operations are mobile and may be constantly moving ahead or from one location to another. In an effort to be as efficient as possible, we try to expedite the work through the use of specialized equipment that improves work production. Chances are the workers you see are just part of a larger crew that is operating the other vehicles. In many cases, it takes as many as three additional vehicles to perform the traffic control which allows the main work operation to proceed.

15. Why do you need to close a bridge for inspection?

A. This really depends on the type of bridge and how extensive the inspection is. In most cases, we do maintain traffic at some level with lane closures. If there is a major inspection effort or a safety concern, the bridge may have to be closed.

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