Safety Eligibility Letter B-141F

U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

October 1, 2010

In Reply Refer To:
HSSD/B-141F

Mr. Brian Smith
Trinity Highway Products, LLC
P.O. Box 568887
Dallas, TX 75356-8887

Dear Mr. Smith:

This letter is in response to your request for the Federal Highway Administration (FHWA) acceptance of modifications to your CASS cable barrier safety system for use on the National Highway System (NHS).

Name of system:	Trinity's Cable Safety System (CASS S3 4:1)
Type of system:	Four cable median and roadside barrier system
Test Level:	NCHRP Report 350: Test Level 3 on 1:4 slopes or flatter Test Level 4 on 1:6 slopes or flatter
Testing conducted by:	Texas Transportation Institute
Date of request:	March 5, 2010

You requested that we find this system acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended "

Requirements
Roadside safety systems should meet the guidelines contained in the NCHRP Report 350. The FHWA memorandum "Identifying Acceptable Highway Safety Features" of July 25, 1997, provides further guidance on crash testing requirements of longitudinal barriers.

Description
The CASS S3 4:1 is a tensioned, four-cable barrier system that was tested with standard (non-prestretched) cables. The top two cables are positioned within a wave-shaped slot in the web of S75 x 8 (S3 x 5.7 in English units) structural I-beam posts. The bottom two cables are supported on flanges of the I-beam post by an 8-mm (5/16-inch) hook bolt with the open end down, with the lowest cable located on the median-side flange and the next lowest cable located on the traffic-side flange.

The proprietary S75 × 8 (S3 × 5.7) posts were installed in steel tube sleeves set in 305-mm (12-inch) diameter x 762-mm (30-inch) deep concrete footings. The cables within the wave-shaped slot are separated by a plastic spacer. A stainless steel strap is mounted on the outside of the post above the top cable.

The 3/4-inch diameter standard (non-pre-stretched) cables were set at heights of 450mm, 755mm, 960 and 1070mm (17.75, 29.75, 37.875, and 42.125 inches) above the ground surface, measured to the center of each cable. Tension of the cables was set at 24.9 kN (5,600 pounds
force) for the tests.

The 104.7-m (343-foot, 6-inch) test installations were anchored by Texas Transportation Institute (TTI) Breakaway Cable Anchor Terminals which were accepted by the FHWA on August 29, 2002.

Four tests were conducted with the CASS S3 4:1 system installed in a 9.1m (30 foot 0 inch) wide depressed median with 1V: 4H side slopes, and one test with the CASS S3 4:1 system installed on level terrain:

1. The NCHRP Report 350 Test 3-11 (modified) - 2270P at 102.6 km/hour (63.7 mph) with a 25.4 degree impact angle. The test article was the CASS S3 4:1 with 3.2-m (10-foot, 6-inch) post spacing installed on the foreslope of a 9.1-m (30-foot, 0-inch) wide depressed median with 1V: 4H side slopes at 1.22m (4 foot, 0 inch) from the break point.

   The CASS S3 4:1 on 1V:4H foreslope contained and redirected the 2270P vehicle. The vehicle did not penetrate, under ride, or override the installation. Dynamic deflection in Test 3-11 (modified) with 3.2-m (10-foot, 6-inch) post spacing was reported by TTI to be 2.16m (7.1 feet).

2. The NCHRP Report 350 Test 3-10 - 820C at 102.1 km/hour (63.4 mph) with a 20.8 degree impact angle. The test article was the CASS S3 4:1 with 6.1-m (20-foot, 0-inch) post spacing installed on the backslope of the 9.1-m (30-foot, 0-inch) wide depressed median at 3.35m (11 feet 0 inch) from the median bottom. The test vehicle crossed the median bottom and traveled up the backslope before impacting CASS S3 4:1.

   The CASS S3 4:1 on 1V:4H backslope contained the 820C vehicle, which then sideslipped along the system until loss of contact. The vehicle did not penetrate, under ride, or override the installation. Dynamic deflection in Test 3-10 (backslope) with 6.1-m (20-foot, 0-inch) post spacing was reported by TTI to be 1.34m (4.4 feet).

3. The NCHRP Report 350 Test 3-10 - 820C at 97.3 km/hour (60.4 mph) with a 19.5 degree impact angle. The test article was the CASS S3 4:1 with 3.2-m (10-foot, 6-inch) post spacing installed on the foreslope of a 99.1-m (30-foot, 0-inch) wide depressed median with 1V: 4H side slopes at 1.22m (4 foot, 0 inch) from the break point.

   The CASS S3 4:1 on 1V:4H foreslope contained and redirected the 820C vehicle. The vehicle did not penetrate, under ride, or override the installation. Dynamic deflection in Test 3-10 with 3.2-m (10-foot, 6-inch) post spacing was reported by TTI to be 1.04m (3.4 feet).

4. The NCHRP Report 350 Test 3-11 (modified) - 2270P at 102.4 km/hour (63.6 mph) with a 25.4 degree impact angle. The test article was the CASS S3 4:1 with 6.4-m (21-foot, 0-inch) post spacing installed on the foreslope of a 9.1-m (30-foot, 0-inch) wide depressed median with 1V: 4H side slopes at 1.22m (4 foot, 0 inch) from the break point.

   The CASS S3 4:1 on 1V:4H foreslope contained and redirected the 2270P vehicle. The vehicle did not penetrate, under ride, or override the installation. Dynamic deflection in Test 3-11 (modified) with 6.4-m (21-foot, 0-inch) post spacing was reported by TTI to be 2.59m (8.5 feet).

5. The NCHRP Report 350 Test 4-12 - 8000S at 79.9 km/hour (49.6 mph) with a 13.6 degree impact angle. The test article was the CASS S3 4:1 with 3.2-m (10-foot, 6-inch) post spacing installed on level terrain.

   The CASS S3 4:1 on flat ground contained and redirected the 8000S vehicle. The vehicle did not penetrate, under ride, or override the installation. Dynamic deflection in Test 4-12 with 3.2-m (10-foot, 6-inch) post spacing was reported by TTI to be 2.42m (8.0 feet).

The 4-cable barrier systems described above are acceptable for use on the designated 1V:4H or flatter slopes under NCHRP Report 350 Test Level 3 or 4 conditions as noted. The systems are detailed in the enclosed drawings and are acceptable for use on the NHS when such use is

Findings
The 4-cable barrier systems described above are acceptable for use on the designated 1V:4H or flatter slopes under NCHRP Report 350 Test Level 3 or 4 conditions as noted. The systems are detailed in the enclosed drawings and are acceptable for use on the NHS when such use is acceptable to a highway agency.

Although the barrier performed well under idealized test impact conditions, the likelihood of passenger car underrides of any cable system may increase as the post spacing increases, particularly when the barrier is installed on non-level or slightly irregular terrain and the cables are not restrained from lifting at each post. Consequently, some transportation agencies have limited post spacing to approximately 6m (20 feet) for cable barriers. The dynamic deflection of the barrier is likely to increase when it is installed along the convex sides of horizontal curves,

Please note the following standard provisions that apply to FHWA letters of acceptance:

• This acceptance is limited to the crashworthiness characteristics of the systems and does not cover their structural features, nor conformity with the Manual on Uniform Traffic Control Devices.
• Any changes that may adversely influence the crashworthiness of the system will require a new acceptance letter.
• Should the FHWA discover that the qualification testing was flawed, that in-service performance reveals unacceptable safety problems, or that the system being marketed is significantly different from the version that was crash tested, we reserve the right to modify or revoke our acceptance.
• You will be expected to supply potential users with sufficient information on design and installation requirements to ensure proper performance.
• You will be expected to certify to potential users that the hardware furnished has essentially the same chemistry, mechanical properties, and geometry as that submitted for acceptance, and that it will meet the crashworthiness require of the FHWA and the NCHRP Report 350.
• To prevent misunderstanding by others, this letter of acceptance is designated as number B-141F and shall not be reproduced except in full. This letter and the test documentation upon which it is based are public information. All such letters and documentation may be reviewed at our office upon request.
• The CASS barriers are patented products and considered proprietary. If proprietary systems are specified by a highway agency for use on Federal-aid projects, except exempt, non-NHS projects, (a) they must be supplied through competitive bidding with equally suitable unpatented items; (b) the highway agency must certify that they are essential for synchronization with the existing highway facilities or that no equally suitable alternative exists: or (c) they must be used for research or for a distinctive type of construction on relativdy short sections of road for experimental purposes. Our regulations concerning proprietary products are contained in Title 23, Code of Federal Regulations, Section 635.411.
• This acceptance letter shall not be construed as authorization or consent by the FHWA to use, manufacture. or sell any patented system for which the applicant is not the patent holder. The acceptance letter is limited to the crashworthiness characteristics of the candidate system and the FHWA is neither prepared nor required to become involved in issues concerning patent law. Patent issues, if any, are to be resolved by the applicant.

Sincerely yours, /* Signature of David A. Nicol */ David A. Nicol, P.E. Director, Office of Safety Design

Enclosures

`

General Information		Impact Conditions		Post-Impact Trajectory
Test Agency	Texas Transportation Institute	Speed	49.6 mi/h	Stopping Distance	348 ft dwnstrm 46 ft twd traffic
Test No.	400001-TCR33	Angle	13.6 degrees	Vehicle Stability
Date	2009-09-04	Location/Orientation	1 ft upstream	Maximum Yaw Angle	-23 degrees
Test Article		Exit Conditions	Post 16	Maximum Pitch Angle	-3 degrees
Type	Longitudinal Barrier	Speed	Not obtainable	Maximum Roll Angle	1 degrees
Name	Trinity CASS	Angle	Not obtainable	Vehicle Snagging	No
Installation Length	343.5 ft.	Occupant Risk Values		Vehicle Pocketing	No
Material or Key Element	4 wire ropes supported by slotted S3x5.7 support posts spaced at 10 ft-6 inches	Impact Velocity		Test Article Deflections
Soil Type and Condition	Concrete footings in crushed limestone, dry	Longitudinal	3.6 ft/s	Dynamic	~8 ft
Test Vehicle		Lateral	4.9 ft/s	Permanent	0.9 ft
Type/Designation	8000s	Ridedown Accelerations
Make and Model	1994 International NaviStar 4700	Longitudinal	-1.4 G	Working Width	9.1 ft
Curb	12,400 lb	Lateral	-1.3 G	Vehicle Damage
Test Inertial	17,710 lb	THIV	6.4 km/h	VDS	01RFQ1
Dummy	No dummy	PHD	0.12	CDC	01RFEW1
Gross Static	17,710 lb	Max. 0.050-s Average		Max. Exterior Deformation	1.5 inches
		Longitudinal	-06.g	Max. Exterior Deformation	1.5 inches
		Lateral	-1.1G
		Vertical	0.4 G

Figure 15. Summary of results for NCHRP Report 350 test 4-12 on the Trinity CASS on level ground.

General Information		Impact Conditions		Post-Impact Trajectory
Test Agency	Texas Transportation Institute	Speed	60.4 mi/h	Stopping Distance	214 ft dwnstrm 30 ft twd traffic
Test No.	400001TCR35	Angle	19.5 degrees	Vehicle Stability
Date	2009-10-08	Location/Orientation	Midspan btw posts 15&16	Maximum Yaw Angle	32 degrees
Test Article		Exit Conditions		Maximum Pitch Angle	9 degrees
Type	Cable Barrier	Speed	Not obtainable	Maximum Roll Angle	14 degrees
Name	Trinity CASS	Angle	-3.6 degrees	Vehicle Snagging	No
Installation Length	343.5 ft.	Occupant Risk Values		Vehicle Pocketing	No
Material or Key Element	CASS with S3x5.7 posts installed on 4H:1V forslope	Impact Velocity		Test Article Deflections
Soil Type and Condition	Concrete footings in Standard Soil, Damp	Longitudinal	12.8 ft/s	Dynamic	3.4 ft
Test Vehicle		Lateral	12.8 ft/s	Permanent	0.1 ft
Type/Designation	820C	Ridedown Accelerations		Working Width	4.2 ft
Make and Model	1995Suzuki Swift	Longitudinal	-5.3G	Vehicle Damage
Curb	1881 lb	Lateral	6.3 G	VDS	11LFQ3
Test Inertial	1850 lb	THIV	18.2 km/h	CDC	11FDEW3
Dummy	167	PHD	7.5 G	Max. Exterior Deformation	10.6 inches
Gross Static	2017 lb	Max. 0.050-s Average		Max.Occupant Compartment Deformation	0.6 inches
		Longitudinal	-2.9 G
		Lateral	4.3 G
		Vertical	3.7 G

Figure 16. Summary of results for NCHRP Report 350 test 3-10 on the Trinity CASS with S3x5.7 posts installed on a 4H:IV forslope.

General Information		Impact Conditions		Post-Impact Trajectory
Test Agency	Texas Transportation Institute	Speed	63.7 mi/h	Stopping Distance	425 ft dwnstrm 83 ft twd traffic
Test No.	40000-1TCR32	Angle	25.4 degrees	Vehicle Stability
Date	2009-08-12	Location/Orientation	At post 16	Maximum Yaw Angle	39 degrees
Test Article		Exit Conditions		Maximum Pitch Angle	-6 degrees
Type	Longitudinal Barrier	Speed	Out of view	Maximum Roll Angle	28 degrees
Name	CASS on 4H:1V Slope	Angle	Not obtainable	Vehicle Snagging	No
Installation Length	343.5 ft.	Occupant Risk Values		Vehicle Pocketing	Yes
Material or Key Element	CASS with S3x5.7 posts spaced at 10ft-6 inches on 4V:H1 forslope	Impact Velocity		Test Article Deflections
Soil Type and Condition	Cruch Limestone, Dry	Longitudinal	8.2 ft/s	Dynamic	7.1 ft
Test Vehicle		Lateral	13.4 ft/s	Permanent	0.5 ft
Type/Designation	2270P	Ridedown Accelerations		Working Width	8.2 ft
Make and Model	2003 Dodge 1500 Quad	Longitudinal	-3.5G	Vehicle Damage
Curb	4871	Lateral	4.3 G	VDS	11LFQ1
Test Inertial	5007	THIV	15.9 km/h	CDC	11LFEW2
Dummy	No Dummy	PHD	5.0 G	Max. Exterior Deformation	10.6 inches
Gross Static	5007	Max. 0.050-s Average		Max.Occupant Compartment Deformation	0
		Longitudinal	-2.0 G
		Lateral	3.5 G
		Vertical	-2.9 G

Figure 11. Summary of results for NCHRP Report 350 test 3-11 on CASS with S3x5.7 posts on 4H:IV forslope.

General Information		Impact Conditions		Post-Impact Trajectory
Test Agency	Texas Transportation Institute	Speed	63.6 mi/h	Stopping Distance	73.5 ft dwnstrm Within cables
Test No.	400001-TCR32	Angle	25.4 degrees	Vehicle Stability
Date	2009-11-08	Location/Orientation	At post 13	Maximum Yaw Angle	32 degrees
Test Article		Exit Conditions		Maximum Pitch Angle	-12 degrees
Type	Wire Rope Barrier	Speed	Out of view	Maximum Roll Angle	-57 degrees
Name	CASS with S3x5.7 posts/4H:1V foreslope	Angle	Out of view	Vehicle Snagging	No
Installation Length	343.5 ft.	Occupant Risk Values		Vehicle Pocketing	No
Material or Key Element	CASS with S3x5.7 posts installed 4V:1V forslope	Impact Velocity		Test Article Deflections
Soil Type and Condition	Standard Soil, Dry	Longitudinal	8.8 ft/s	Dynamic	8.5 ft
Test Vehicle		Lateral	12.5 ft/s	Permanent	3.0 ft
Type/Designation	2270P	Ridedown Accelerations		Working Width	9.8 ft
Make and Model	2004 Dodge Ram1500 Quad-Cab	Longitudinal	-4.1G	Vehicle Damage
Curb	4772 lb	Lateral	5.9 G	VDS	11LFQ2
Test Inertial	5026 lb	THIV	15.2 km/h	CDC	11DEW2
Dummy	No Dummy	PHD	6.1 G	Max. Exterior Deformation	7.5 inches
Gross Static	5026 lb	Max. 0.050-s Average		Max.Occupant Compartment Deformation	0
		Longitudinal	-2.0 G
		Lateral	3.6 G
		Vertical	-1.8 G

Figure 16. Summary of results for NCHRP Report 350 test 3-11 on the CASS with S3x5.7 posts installed on 4H:IV forslope.

General Information		Impact Conditions		Post-Impact Trajectory
Test Agency	Texas Transportation Institute	Speed entering ditch	63.4 mi/h	Stopping Distance	35 ft dwnstr 11 ft field side
Test No.	40000-1TCR34	Angle entering ditch	20.8 degrees	Vehicle Stability
Date	2009-10-12	Speed at wire rope	60.8 mi/h	Maximum Yaw Angle	-172 degrees
		Angle at wire rope	24.0 degrees
		Location/Orientation	Mispan 13-14
Test Article		Exit Conditions		Maximum Pitch Angle	26 degrees
Type	Median Barrier	Speed	Out of view	Maximum Roll Angle	-34 degrees
Name	Trinity CASS	Angle	Out of view	Vehicle Snagging	Yes
Installation Length	342 ft.	Occupant Risk Values		Vehicle Pocketing	No
Material or Key Element	S3x5.7 posts installed on a 4H:1V backslope	Impact Velocity		Test Article Deflections
Soil Type and Condition	Concrete footings in standard soil, damp	Longitudinal	18.7 ft/s	Dynamic	4.4 ft
Test Vehicle		Lateral	2.3 ft/s	Permanent	1.9 ft
Type/Designation	820C	Ridedown Accelerations		Working Width	5.2 ft
Make and Model	1997 Geo Metro	Longitudinal	-8.9 G	Vehicle Damage
Curb	1797 lb	Lateral	-8.6 G	VDS	11LFQ4
Test Inertial	1861 lb	THIV	19.2 km/h	CDC	11FLEW3
Dummy	165 lb	PHD	11.9 G	Max. Exterior Deformation	9.8 inches
Gross Static	2026 lb	Max. 0.050-s Average		Max.Occupant Compartment Deformation	1.2 inches
		Longitudinal	-7.8G
		Lateral	-4.4 G
		Vertical	-5.4 G

Figure 15. Summary of results for NCHRP Report 350 test 3-10
on the Trinity CASS with S3x5.7 posts installed on a 4H:IV backslope.