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Chevron Panels and Other Highway Safety Systems: Guidelines for Use

Protecting all those who use the nation’s transportation system is what chevron panels and other highway safety systems are all about.  Even the best products may not provide enough protection, though, unless installed and used properly.  This post will look at proven steps for using many of these products.  Since this is a high-level overview of the topic, readers should consult the MUTCD or other official resources for detailed information.

Chevron Panels: Design and Installation

Chevron panels consist of a vertical rectangle with no outlining border with directional arrows.  Chevron panels should be installed on the outer edges of a turn or curve and at a right angle to oncoming traffic.  Crews should install chevron panels so that drivers can view at least two of the markers at the same time.  Enough chevron panels should be used so that motorists have enough time to react to changes in road alignment.

Roundabouts

A roundabout is a circle-shaped intersection with three basic characteristics:

1.     It reduces driving speeds to promote safety.

2.     It causes oncoming traffic to yield to vehicles in the circular roadway.

3.     It reduces potential conflict between motorists.

 

Roundabouts are especially effective in areas where standard highway safety systems, such as signal lights, have proven ineffective.  Studies show that converting a signalized intersection to a roundabout can reduce accidents by as much as 48% and fatalities by as much as 78%.  Roundabouts are thus an excellent tool for promoting public safety, making them a popular option in many locations.

Access Management Measures

The term “access management” refers to a set of measures used by state and local governments to govern how motorists use entry and exit points along streets and highways.  Some of the more common techniques for doing so include:

·       Closing, relocating, or consolidating driveways

·       Establishing right-in/right-out turns

·       Creating J-turns, U-turns, and/or quadrant roadways at intersections

·       Building raised medians to prevent cross-road movement

·       Adding low-speed frontage roads for highway access

Rumble Strips and Stripes for Two-Lane Roads

The term “rumble strips” refers to milled or raised roadway sections designed to command the attention of tired or distracted drivers.  Rumble strips can be used in a variety of ways, including:

·       Shoulder-placed rumble strips designed to prevent motorists from running off the road.

·       Centerline rumble strips placed in the middle of an undivided highway.  These are intended to prevent cross-roadway or “head-on” collisions.

·       Painted stripes are placed over pavement markings to increase the marking’s nighttime visibility.

Rumble strips and stripes are particularly effective at preventing accidents in which a single vehicle strays from the correct travel lane.  Statistics show that these types of errors cause approximately 53% of fatal accidents.  Studies also show that rumble strips have the following beneficial effects:

·       44% reduction of head-on crashes on rural two-lane roadways

·       64% reduction of head-on crashes on urban two-lane roadways

·       36% reduction of accidents in rural areas in which a vehicle runs off the road

Backplates

Backplates are metal plates made with special retroreflective materials.  They are placed behind a traffic-signaling device to improve its visibility to oncoming drivers.  The widespread use of backplates stems from a 1998 study that revealed their ability to capture the attention of otherwise inattentive or drowsy motorists.

Backplates are particularly useful during power outages and at night, when the signal may otherwise be too dark for drivers to see. They offer an outstanding cost versus benefit ratio, making their widespread use advisable.

Conclusion

Chevron panels, backplates, rumble strips and stripes, roundabouts, and access management measures are all valuable parts of a public official’s toolkit.  Used wisely, they can prevent thousands of accidents each year, helping to ensure that America’s transportation network remains both safe and user-friendly.

http://mutcd.fhwa.dot.gov/htm/2003r1/part2/part2c.htm#section2C10

http://safety.fhwa.dot.gov/provencountermeasures/