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IF we are using the NYDOT cable barrier terminal, what is the estimated length of need for this system for impacts on both the upstream and downstream ends of the system?

I reviewed the NY cable anchor report to help in the determination of the beginning of length of need for impacts on your cable terminal.

For the downstream impacts, test nos. 98 and 104 are applicable.

1.         Test 98 was a 1800 lb small car impacting 39.4' upstream of the downstream anchor at 55.8 mph  and 11 degrees. Test no. 98 gated.

2.         Test 104 was a 1800 lb small car impacting 43.5 upstream of the downstream anchor at 61.8 mph  and 15 degrees. Test no. 104 gated.

3.         Test 100 was a 4780 lb sedan impacting 99' upstream of the downstream anchor at 57.7 mph  and 23 degrees. Test no. 100 redirected.

Based on these tests, it appears that the minimum length that you can assume for redirection for reverse direction impacts would be greater than 43.5' upstream of the anchor. However, the minimum length from the downstream anchor where redirection will occur cannot be accurately defined from the data in the report. Test no. 100 on middle of the system LON was conducted 99' upstream of the end anchor and redirected. This would indicate that the system is capable of redirection for vehicles impacting 99' upstream of the downstream anchor. This is likely a conservative estimate, but it is all we have for a basis.

For the upstream impacts, test no. 107 is applicable.

1.         Test 107 was a 4850 lb sedan impacting 38' downstream of the upstream anchor at 56.5 mph  and 25 degrees. Test no. 107 redirected.

The results from test no. 107 indicate that the system is capable of redirecting impacting vehicles 38' downstream of the anchorage. The IS value for this test is approximately 9% less than the NCHRP 350. This test had a 38% higher IS value than NCHRP 350 test 3-35, so it is safe to assume that the system can safely redirect vehicles impacting a minimum of 38' downstream of the anchorage.