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Traffic Lane Dividers: What Options Do You Have?

Traffic lane dividers play a vital role in ensuring public safety.  The Manual of Uniform Traffic Control Devices (MUTCD) specifies several types of dividers that are suitable for given situations.

 

Temporary Raised Islands

These are appropriate when daily traffic volume ranges between 4,000-15,000 units per day for standard roadways and between 22,000-60,000 per day for freeways.  Temporary raised islands should be at least four inches (100 mm) high and 128 inches (450 mm) wide, with chamfered or rounded corners.

 

Opposing Traffic Lane Dividers

These are useful in two-lane, opposing traffic situations, usually temporarily created for construction zones.  They should never be used where pedestrian crossings are present.  An opposing traffic lane divider sign should always be used at these locations.

 

Semi-Permanent Pavement Markings

When these are used, they must first be placed at regular intervals along the area where the detour exists prior to opening it to vehicular traffic.  When they’re no longer needed, the markings should be destroyed so that no evidence remains.  The markings must be readily visible during day, evening, and twilight conditions, whether the pavement is wet or dry.

 

Temporary Pavement Markings

Unlike semi-permanent markings, these should be used for as short a time period as possible.  In general, they should never be kept in place for more than two weeks, unless an engineering study deems a longer placement necessary. 

 

Raised Pavement Markers

When these are used, a retroreflective marker should be placed every two to five feet (0.6 to 1.5 m) along the modified length of road surface.  They are appropriate for use along temporary roadways or surfaced detours.

 

Delineators

These should be used in a supplementary role to other traffic lane modifiers, but never as the primary tool.  For two-way streets or the right side of one-way roadways, the standard color for delineators should be white; for the left side of one-way streets, yellow should be the standard color.  Delineators should be generously used, so that several are visible at all times to drivers.

 

Lighting Devices

These fall into four primary categories:

 

  1. Floodlights
  2. Flashing warning beacons
  3. Warning lights
  4. Steady burning electric lamps

 

Lighting devices are suitable as supplements to other types of devices, such as retro-reflective signs, channelizing devices, and barriers.  When floodlights are used, workers should perform a drive-through of the setup to ensure that oncoming drivers will not be troubled by an oncoming glare.

 

Temporary Traffic Control Signals

These are useful in temporary one-way operations on two-way roads, bridges, intersections, and reversible lanes.  Workers should exercise special caution to avoid confusion between temporary and permanent control signals. 

 

Temporary Traffic Barriers

These devices create a physical barrier to entry for vehicular traffic while minimizing the risk of injury for vehicle occupants.  They can also be used to separate opposing lanes of traffic in two-way lane situations.  Warning lights may be installed in temporary barriers to heighten their visibility.

 

Crash Cushions

These traffic safety products are used to lessen the risks of injury or death for occupants of vehicles that strike traffic barriers.  They either redirect the vehicle or slow its rate of impact.  Truck-mounted attenuators fall under this category.  Vehicle-arresting nets are similar in design and intent.

 

Rumble Strips

These are rough-textured strips of material that alert drivers to changing road conditions with sounds and vibrations.  Often the distance between rumble strips narrows as the vehicle nears the unusual conditions.  Rumble strips are usually the same color as the surrounding pavement. 

 

Screens / Shields

These are used to block a driver’s view of work and other activities that may be distracting.  They create a psychological rather than a physical deterrent to errant vehicles.

 

Summary

So long as the nation’s road system requires periodic maintenance, the danger of vehicular collisions with road crews and equipment will remain.  However, traffic lane dividers will continue to mitigate these risks, helping to ensure the safety of both private drivers and public workers.