Delaware Administrative Code
Title 2 - Transportation
2000 - Department of Transportation
2400 - Division of Transportation Solutions
2402 - Manual on Uniform Traffic Control Devices (MUTCD)
Part 6 - Temporary Traffic Control
Chapter 6F - TEMPORARY TRAFFIC CONTROL ZONE DEVICES
Section 6F.86 - Crash Cushions

Universal Citation: 2 DE Admin Code 6F.86

Current through Register Vol. 28, No. 3, September 1, 2024

Support:

01 (DE Revision) In Delaware, crash cushions typically refer to sand crash cushion arrays and impact attenuators. Crash cushions are systems that mitigate the effects of errant vehicles that strike obstacles, either by smoothly decelerating the vehicle to a stop when hit head-on, or by redirecting the errant vehicle. The two types of crash cushions that are used in TTC zones are stationary crash cushions and truck-mounted attenuators. Crash cushions in TTC zones help protect the drivers from the exposed ends of barriers, fixed objects, shadow vehicles, and other obstacles. Specific information on the use of crash cushions can be found in AASHTO's "Roadside Design Guide" (see Section 1A.11).

Standard:

02 Crash cushions shall be crashworthy. They shall also be designed for each application to stop or redirect errant vehicles under prescribed conditions. Crash cushions shall be periodically inspected to verify that they have not been hit or damaged. Damaged crash cushions shall be promptly repaired or replaced to maintain their crashworthiness.

Support:

03 Stationary crash cushions are used in the same manner as permanent highway installations to protect drivers from the exposed ends of barriers, fixed objects, and other obstacles.

Standard:

04 Stationary crash cushions shall be designed for the specific application intended.

Guidance:

04A (DE Revision) The following factors should be considered when selecting the type of crash cushion or impact attenuator:
A. Speed of vehicles;

B. Duration of use (maintenance);

C. Width of device;

D. Cross-section of roadway (pavement and slope); and

E. Direction of impact.

F. Runout area behind attenuator/barrier

04B (DE Revision) Sand crash cushion arrays should not be used in applications that could result in a reverse strike by vehicles traveling in the opposite direction. It is acceptable to use sand crash cushion arrays if they are outside the clear zone of the opposite direction of traffic.

Standard:

04C (DE Revision) Sand crash cushions shall be designed according to manufacturer's recommendations and NCHRP 350 or MASH approved testing methods.

Guidance:

04D (DE Revision) If it is expected that sand crash cushions will be used in conditions where freezing could be expected, a suitable mixture of material should be used to preclude the ballast from freezing.

Option:

04E (DE Revision) Sand crash cushions may be used for short-duration maintenance purposes or for long-term projects where it is infeasible to install an impact attenuator.

Guidance:

04F (DE Revision) Stationary impact attenuators should be used instead of sand crash cushions for most long-term projects and, where practical, for short-duration maintenance purposes.

04G (DE Revision) Except for short-duration maintenance purposes, sand crash cushions should not be used without DelDOT Traffic approval.

Standard:

05 Truck-mounted attenuators shall be energy-absorbing devices attached to the rear of shadow trailers or trucks. If used, the shadow vehicle with the attenuator shall be located in advance of the work area, workers, or equipment to reduce the severity of rear-end crashes from errant vehicles.

05A (DE Revision) For long-term, intermediate-term, short-term, and mobile operations requiring shoulder and/or lane closures, a truck-mounted attenuator shall be used on roadways with a posted speed limit or 85th-percentile speed greater than 40 miles per hour, except as provided in Paragraphs 5B, 5C and 5E.

Option:

05B (DE Revision) For short-duration operations of 15 minutes or less along roadways with a posted speed limit or 85th-percentile speed greater than 40 miles per hour, a truck-mounted attenuator may be omitted if a vehicle with activated high-intensity rotating, flashing, oscillating, or strobe lights is used or if the shoulder width is less than the width of a truck-mounted attenuator.

05C (DE Revision) Truck-mounted attenuators may be omitted from specialized work vehicles, such as sweeper, vacuum, and pothole patching trucks, and other work vehicles that cannot support the installation of a truck-mounted attenuator.

05D (DE Revision) Truck-mounted attenuators may be used for all operations along roadways with a posted speed limit or 85th-percentile speed less than or equal to 40 miles per hour based on engineering judgment.

05E (DE Revision) If a shadow vehicle is used for mowing operations along a two-way, two-lane road, a truck-mounted attenuator may be omitted.

Support:

06 Trucks or trailers are often used as shadow vehicles to protect workers or work equipment from errant vehicles. These shadow vehicles are normally equipped with flashing arrows, changeable message signs, and/or high-intensity rotating, flashing, oscillating, or strobe lights located properly in advance of the workers and/or equipment that they are protecting. However, these shadow vehicles might themselves cause injuries to occupants of the errant vehicles if they are not equipped with truck-mounted attenuators.

Guidance:

07 (DE Revision) The shadow truck should be positioned a sufficient distance in advance of the workers or equipment being protected so that there will be sufficient distance, but not so much so that errant vehicles will travel around the shadow truck and strike the protected workers and/or equipment. This "roll-ahead" distance should be based on the truck-mounted attenuator manufacturer's specifications.

Support:

08 Chapter 9 of AASHTO's "Roadside Design Guide" (see Section 1A.11) contains additional information regarding the use of shadow vehicles.

Guidance:

09 If used, the truck-mounted attenuator should be used in accordance with the manufacturer's specifications.

Disclaimer: These regulations may not be the most recent version. Delaware may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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