NJDOT Roadway Design Manual - Section 9. State of New Jersey. Department of Transportation. Roadway Design Manual. Section 9 - Guidelines for the Selection and Design of Crash Cushions.
See Section 10, 'Drainage Design' for the. roadway shoulders designed to NJDOT. the designer should review Section 5.2., Geometrics on Design Manual. Construction Access” to Section 3.8.3. the NJDOT 2007 Roadway Design Manual and 2009 Design. Njdot Access Design Manual Created Date: 10/22/2015 12. Njdot Design Manual NJDOT Engineering. NEW design guidelines in section 8 of the NJDOT roadway design manual. Njdot Design Manual Created Date: 10/9. Section 10 - Drainage Design. Download the print ready Roadway Design Manual (zip 32m). Roadway design should lead the driver to adopt a driving behavior.
Section. 9. 1 Introduction. Selection Guidelines.
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General. 9. 2. 2 Dimensions of the Obstruction. Space Requirement. Geometrics of the Site.
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Physical Conditions of the Site. Redirection Characteristics. Design Speed. 9. 2. Foundations. 9. 2. Backup Structure Requirements.
Anchorage Requirements. Flying Debris Characteristics. Initial Cost. 9. 2.
Njdot Roadway Design Manual Section 14. Section 9.5.1 that Chapter 10. Pavement Design. 4.1. 8/25/14. Chapter 11. Other Project Types. 4.3. 5/11/15. Roadway Design Manual Section 9. review the design instructions and product limitations in the manufacturer's design manual. and a 10’ long tapered section.
Roadway Design Manual Section 13 Guidelines For The Design Of. For signs not included in the NJDOTStandard Roadway. but not less than 10 ft. from. Maintenance will cover the NEW design guidelines in section 8 of the NJDOT roadway design manual for guiderail design and. 10 Embankment either NYDOT or NJDOT.
Maintenance. 9. 3 Design Procedure. Inertial Barriers.
Compressive Barriers. Product Information. Tables. 9- 1 Quad. Guard II9- 2 SCI9- 3 TRACC9- 4 Universal TAU- II9- 5 Quad. Guard Elite. 9- 6 REACT 3.
Quad. Guard II CZ9- 8 REACT 3. WZ9- 9 Min Foundation Req.
Backup Structures. Figures. 9- A Crash Cushions - Flat.
B Suggested Layout. C Reserve Area Details. D Typical Sand Barrel Config. E Typical Sand Barrel Config. F Typical Sand Barrel Config.
G Temporary Crash Cushion. H Compressive Barrier Summary. Forms. DF1. 5 Request for Approval of Patented/Proprietary Items on FHWA Funded Contract. DF1. 6 Request for Approval of Patented/Proprietary Items on Non- FHWA Funded Contract.
Introduction Fixed objects within the clear zone distance should be removed, relocated or modified so as to be breakaway. When this is not practical, the obstruction should be shielded so as to prevent an impact of the obstruction by an errant vehicle. A detailed discussion on warranting obstructions and clear zone distance can be found in Section 8, “Guidelines for Guide Rail Design and Median Barriers”. A crash cushion is a type of traffic barrier that can be used to shield warranting obstructions such as overhead sign supports, bridge piers, bridge abutments, ends of retaining walls, bridge parapets, bridge railings, longitudinal barriers, etc. Due to the maintenance needs of crash cushions, the designer should, when practical, attempt to place obstructions beyond the clear zone, or provide designs that will avoid the need to require shielding by a crash cushion. The most common use of a crash cushion is to shield a warranting obstruction in a gore. However, warranting obstructions in the median and along the roadside can also be shielded with a crash cushion (see Figure 9- A).
Selection Guidelines. General Once it has been determined that a crash cushion is to be used to shield a warranting obstruction, a choice must be made as to which crash cushion is best for the particular location under consideration. Several factors must be evaluated when determining which of the recommended crash cushions should be used. There is therefore no simple, systematic selection procedure. The factors that normally should be considered are briefly discussed in the following later subsections: • Dimensions of the Obstruction• Space Requirement• Geometrics of the Site• Physical Conditions of the Site• Redirection Characteristics• Design Speed• Foundations• Backup Structure Requirements• Anchorage Requirements• Flying Debris Characteristics• Initial Cost• Maintenance. In many cases, evaluation of the first few items will establish the type of crash cushion to be used. When designing a crash cushion, review the design instructions and product limitations in the manufacturer's design manual thoroughly before performing the necessary work.
The following crash cushions are presently recommended for permanent and temporary installations (Subsections 9. A thru E) on Departmental projects. Existing crash cushions that are not of the type listed below shall be evaluated to determine whether repairs or replacement are necessary. A. Inertial Barriers The following inertial barriers may be used in permanent and temporary installations.
These barriers consist of sand filled plastic barrels containing varying amounts of sand ranging from 2. Sand filled plastic barrels when impacted at an angle near the front of the system allow an impacting vehicle to pass through (gating). When impacted on the side, the system will contain and capture the impacting vehicle (non- redirective). Energite III Inertial Barrier. Universal Inertial Barrier. Big Sandy Inertial Barrier.
B. Compressive Barriers. The following compressive barrier systems may be used in permanent installations. When impacted at an angle near the front of the system, the barrier will capture the errant vehicle (non- gating), and when impacted downstream from the front of the system, it will redirect the vehicle away from the hazard. These systems can be installed between opposing directions of traffic (bidirectional). However, a transition will be required on the reverse traffic side of the backup structure.
Quad Guard II• Shield narrow to x- wide obstructions• Design speeds 2. See Table 9- 1. 2. SCI• Shield narrow to x- wide obstructions• Design speeds 2. See Table 9- 2 3. TRACC• Shield narrow to wide obstructions• Design speeds 2. See Table 9- 3 4. Universal TAU- II• Shield narrow to x- wide obstructions• Design speeds 2. See Table 9- 4 C. Low Maintenance Compressive Barriers Low maintenance compressive barrier systems shall be used in permanent installations to shield obstructions when the posted speed is 4. ADT is 2. 5,0. 00 or greater and the through lane would need to be closed while repairs are being made.
In addition, a low maintenance compressive barrier should be used in gore areas when the horizontal and/or vertical sight distance approaching the gore area requires a design exception. A low maintenance compressive barrier should also be installed to replace an existing standard compressive barrier or inertial barrier that has been impacted two or more times within an eight- year period. The following low maintenance compressive barrier systems are energy absorbing crash cushions that are bidirectional, non- gating, redirective and reuseable. Quad Guard Elite• Shield narrow to x- wide obstructions• Design speeds 2.
See Table 9- 5. 2. REACT 3. REACT 3. 50 II• Shield medium width obstructions• Design speeds 2. See Table 9- 6 3. SCI • Shield narrow to x- wide obstructions• Design speeds 2. See Table 9- 2 D. Temporary Compressive Barriers. The following temporary compressive barriers are energy absorbing crash cushions that are bidirectional, non- gating and redirective.
Quad. Guard II CZ• Shield narrow and medium obstructions• Design speeds 2. See Table 9- 7 2. SCI• Shield narrow to x- wide obstructions• Design speeds 2. See Table 9- 2 3. TRACC• Shield narrow to wide obstructions• Design speeds 2. See Table 9- 3 4. Universal TAU- II• Shield narrow to x- wide obstructions• Design speeds 2.
See Table 9- 4. E. Temporary Low Maintenance Compressive Barriers The criteria for when to use a temporary low maintenance compressive barrier are the same as that for low maintenance compressive barriers and should be used when the temporary barrier will be in place for a year or more. The following temporary low maintenance compressive barriers are energy absorbing crash cushions that are bidirectional, non- gating and redirective.
REACT 3. 50. WZ & REACT 3. II WZ• Shield medium width obstructions• Design Speeds 2. See Table 9- 8 2. SCI• Shield narrow to x- wide obstructions• Design Speeds 2. See Table 9- 2. 9. Dimensions of the Obstruction Inertial barriers can be designed to shield obstructions of practically any width. Compressive barrier systems (Quad.
Guard II, TAU- II, TRACC and SCI systems) are used to shield obstructions ranging in width from 2 feet to a maximum of 1. Tables 9- 1 through 9- 8 provides design criteria (system width, system length and design speed) for approved compressive barrier systems. These tables are provided for informational purposes only. The designer should refer to the manufacturer’s product manual for the most up to date information. When the distance in front of the obstruction that is available for the installation of a compressive crash cushion is very limited, the designer shall contact the supplier/manufacturer to determine the exact distance from the front of the crash cushion to the obstruction. The maximum width of the obstruction for the standard Quad. Guard II and TAU- II systems are 1.
The TRACC, Shor. TRACC and Fas. TRACC have a maximum width of 2.
However, the Wide. TRACC has a standard width of 4. The Wide. TRACC can also be customized to fit any width by adding 2.
The standard SCI system is designed to shield obstructions 2. However, wider obstructions can be shielded by using transition assemblies available from the manufacturer to shield obstructions up to 1.
The transition assemblies increase the overall length of the SCI system from approximately 2. Use compressive barriers (Quad. Guard II, SCI, Universal TAU II, or TRACC Systems) or, when warranted, a low maintenance compressive barrier (Quad.
Guard Elite, REACT 3. REACT 3. 50 II, or SCI Systems)as a crash cushion treatment at barrier curb openings in the median. When a low maintenance compressive barrier (Quad. Guard Elite, REACT 3. REACT 3. 50 II and SCI) is warranted the following apply: A. Quad.
Guard Elite 1. The Quad. Guard Elite can be used to shield obstructions up to 7.
B. REACT 3. 50 or REACT 3. II1. The REACT 3. REACT 3. 50 II is used when the design speed is 5.
The REACT 3. 50 and REACT 3. II are available in widths of 3. However, because of their cost, widths greater than 3. Department projects. When using a Self- Contained Backup, the width of the obstruction is limited to 8” in gore areas. Obstructions in non- gore area may be up to 2. If used to shield the end of 2.
Transition hardware is required to connect the Self- Contained Backup to the barrier. If the obstruction has a vertical shape, the system shall be offset from the obstruction toward traffic on the approach side. The offset is accomplished by aligning the vertical face of the cylinder with the rear or trailing face of the vertical barrier/obstruction. If a concrete backup is used, the width of the obstruction that can be shielded may be up to 3.