us. DelXlrtment 

'" Tronsportat;on 

Fedefal Highway 

Administration 

Mr. Rich Peter 

Chief, Roadside Safety Technology Unit 

Office of Materials Engineering and 

Testing Services - MS #5 

P.O. Box 19128 

Sacramento, California 95819-{)128 

Dear Mr. Peter: 

March 6, 1998 

400 Seventh 51.. 5W. 

Washington. D.C. 20590 

Refer to: HNG-14 

In your February 17 letter to Mr. Henry Rentz, you requested Federal Highway Administration's 

acceptance of the California Department of Transportation Type 70 Bridge Rail at the National 

Cooperative Highway Research Program (NCHRP) Report 350 test level 4 (TL-4). To support 

this request, you sent us a copy of your report: "Vehicle Crash Tests of the Type 70 Bridge 

Rail,'" dated January 1998, and a copy of a video tape documenting the certification tests that 

were conducted. 

Our review of this material indicated that the Type 70 Bridge Rail is an 81O-mm tall concrete 

barrier with its traffic face sloped at a constant 9.1 degrees away from traffic. This face 

geometry is identical to your Type 60 roadside/median barrier that was accepted for use on 

the National Highway System (NHS) at TL-3 in my February 4 letter to you. However, the 

Type 70 Bridge Rail has a vertical back face with some architectural treatment and is more 

heavily reinforced than the Type 60. Design details are shown in Enclosure 1. 

We noted that three tests were reported, including test 4-12 with an S{x)() kg Single-unit truck 

impacting the barrier at an angle of 15 degrees and a speed of SO krnIh Each of these tests met 

appropriate NCHRP Report 350 evaluation criteria. The individual test results are summarized in 

Enclosure 2. We noted also that test 4-11 was re-run after a first unsuccessful attempt in which 

the pickup truck rolled over after impact. You theorized that the non-standard floating rear hub 

of the test vehicle caused the drive shaft to pull out of the transmission housing on impact and 

that the shaft then dug into the test track and precipitated the rollover. This test was then re-run 

with a pickup truck with a standard wheel hub. Considering the successful retest and the earlier 

pickup truck tests with your Type 60 constant slope barrier as well as successful pickup tests with 

the New Jersey. F-proftle. and the Texas Department of Transportation constant slope barrier. we 

are willing to consider test 512 (NCHRP Report 350 test 4-11) as an anomaly. 
Based on the above, we consider the California Type 70 Bridge Rail a NCHRP Report 350 TL-4 

design that may be used on the NHS when proposed by a State or local transportation agency. 

Since you did not provide any details on your transition design, nor submit any crash-test results, 

our acceptance is limited at this time to the design of the bridge rail itself. By copy of this letter. 

we will advise OUf field offices of this finding. Please call Mr. Richard Powers of my staff at 

(202) 366-1320, if you have any questions. 

Sincerely yours, 

Dwight A. Horne 

Chief, Federal-Aid and Design Division 

2 Enclosures 

2 
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I I SECTION "" ~ 

"YPICAL SECTION 110 I CALI: 

ALL DIIIIENIIONI ARE IN MIL U IIII!TE"11 UNLE" O'"!RWlle . "OWIt 

IX ..... - ,.. c . .--"so.. STATE OF BRIDOE BARRIER TESTS A , DU . ,cO -"._- - CALIFORNIA 0'''' ' 810N 0' ITIIUCTUII1!' • .... y~~ 1'0 . ... - STRUCTURE DESION • TYPE 73:1 COtlCRETE BARRIER DETAILS ...... ''''n ....... - - I'O.C. __ IO_ DUAllBEJIT Of tulSI'omnal 

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Enclosure 2: Page 1 of 4 

2. TECHNICAL DISCUSSION (Continued) 

Figure 2.13 - Test 511 Data Summary Sheet 

~~ ---------------------- 22.86 ----------------------~~ 

~~~--------- 11.5 m ----------<~~ 

~j[] lD Qi7 

Impact 2.8 m after expansion joint. 

J 

Test Barrier 

Type: Type 70 Bridge Rail 

Length: 22.9 m 

Test Date: May 6, 1997 

Test Vehicle: 

Model: 1992 Geo Metro 

Inertial Mass: 843 kg 

Impact ! Exit Velocity: 104.1 kmlh / 92 kmlh 

Impact 1 Exit Angle: 20.0/12.1 ° 

Test Dummy: 

Type: Hybrid III 

Weight 1 Restraint: 74.8 kg f lap and shoulder 

Position: Front RighI 

Test Data: 

Occ. Impact Velocity (Long f Lat): 4.51 mls 17.22 mls 

Aidedown Acceleration (Long / Lat): -2.9g 1 -1 6.0g 

Max. 50 ms Avg. Accel (Long 1 Lat): -7.0g 1 -13.4g 

Exterior: VDSUl/CDCt&l FA-5. RD-4 / 12AFEW3 

Interior: OCDlll AF0000110 

Barrier Damage: Only superficial scuffing 

15 
Enclosure 2: Page 2 of 4 

2. TECHNICAL OISCUSS..!9"'N.:.....:.::;C.::.o"'nt"'in,;.;u;.:e;.;:d ... ) ____________ _ 

Figure 2.22 • Test 512 Data Summary Sheet 

~·~-------------------- 22.86 m--------------------~~ 

-,----- 7 m ----'.~ 

Impact 1.7 m before expansion joint. 

Test Barrier 

Type: Type 70 Bridge Rail 

Length: 22.9 m 

Test Date: June 11, 1997 

Tes t Vehicle: 

Model: , 991 Ford F250 

Inertial Mass: 2018 kg 

Impact I Exit Velocity: 97.0 km/h / 65 kmlh 

Impact I Exit Angle: 25.10/5° 

Test Dummy: 

Type: NA 

Weight I Restraint: NA 

Position: NA 

Test Data: 

Dce. Impact Velocity (Long I Lat): 6.07 mls I 6.2 mls 

Ridedown Acceleration (l ong I Lat): -6.99 I -6.79 

Max. 50 ms Avg. Accel (Long I Lal): -7.19/.1 4.69 

Exterior: VDS!D/CDCtBl FR-5, RD-51 01 RFEW3 

Interior: OCDw RF0150013 

Barrier Damage: The barrier sustained a 200 mm long gouge just 

upstream from the impact area. The gouge was 20 to 

100 mm wide and 0 to 20 mm deep. 

22 
Enclosure 2: Page 3 of 4 

2. TECHNICAL DISCUSSION (Continued) 

r'·<---- - - --- --- 22.86 m ---------- - --. . , 

; I .. ---- 7.2 m --_ ..

rI 

\ >- - -

Impacl 1.5 m before expansion joint. , 

Test Barrier 

Type: Type 70 Bridge Rail 

Length: 22.9 m 

Test Date: July 23,1997 

Test Vehicle: 

Model: 1991 Ford F250 

Inertial Mass: 2009 

Impact I Exit Velocity : 100A kmlh 1 54 knv'h 

Impact I Exit Angle: 24.2° 18" 

Test Dummy: 

Type: NA 

Weight I Restraint: NA 

POSition: NA 

Test Data: 

Oce. Impact Velocity (Long I Lal): 5.46 mls I 6.16 mls 

Aidedown Acceleration (Long I Lat): -8.29 I -t 4.19 

Max. 50 ms Avg. Accel (Long I La!): -5.79 I -11.99 

Exterior: VDSIZl/CDC(8) FR-S, RD-S I 01 RFEW3 

Interior: OCDIU) RFOOQ1000 

Barrier Damage: Damage consisted of only moderate sc rapi ng and tire 

scuffing over a length of four meters 

38 
.&.:.1.I\:JUsure ;j: Page 4 of 4 

2. TE~NI('AL DISCUSSION (Continued) 

Figure 2.34 - Test 513 Data Summary Sheet 

,- ------------ 22.86 m ------------ " 

~40- 6.5 m ----<.~ 

Impact 2.2 m before expansion joint. 

Test Barrier 

Type: Type 70 Bridge Rail 

Length: 22.9 m 

Test Date: September 3, 1997 

Test Vehicle: 

Model: 1992 GMC Topkick 

Inertial Mass: 8010 kg 

Impact / Exit Velocity: 83.5 kmlh / 71 kmlh 

Impact / Exit Angle: 15.0 / 4<> 

Test Dummy: 

Type: NA 

Weight / Restraint: NA 

Position: NA 

Test Data: 

Dec. Impact Velocity (Long I Lat): not measured 

Ridedown Acceleration (Long / Lat): not measured 

Max. 50 ms Avg. Accel (Long / Lat not measured 

Interior: OCDlllJ RFOOODOOO 

Barrier Damage: The barrier was scraped during the time of vehicle 

contact. Damage was mainly limited to minor spaUing. 

31