Roadside Barriers

RDG Chapter 5

Barrier Types

•Roadside Barriers

•Median Barriers

•Bridge Railings

Barrier Testing: NCHRP 350 (Test Level 3)

STRENGTH TEST

4400 lb.62 mph

25 degrees

SEVERITY TEST

1800 lb.62 mph

20 degrees

NCHRP 350 Test Levels 1-3

Test Level Impact speed Vehicle Type

TL-1 50 kph/30 mph 820kg Car; 2000kg Pickup

(1800 lb.) (4400 lb.)

TL-2 70 kph/45 mph 820kg Car; 2000kg Pickup

(1800 lb.) (4400 lb.)

TL-3 100 kph/62 mph

820kg Car; 2000kg Pickup

(1800 lb.) (4400 lb.)

NCHRP 350 Test Levels 4-6

Test Level Impact Speed Vehicle Type

TL-4 100 kph/62 mph

80 kph/50 mph

820kg Car; 2000kg Pickup

8,000kg Single Unit Truck

(18,000 lb.)

TL-5 100 kph/62 mph

80 kph/50 mph

820kg Car; 2000kg Pickup

36,000kg Tractor Trailer

(80,000 lb.)

TL-6 100 kph/62 mph

80 kph/50 mph

820kg Car; 2000kg Pickup

36,000kg Tanker Truck

(80,000 lb.)

NCHRP 350 Test Levels 4-6

TL-5 Vehicle

TL-6 Vehicle

TL-4 Vehicle

Evaluation Criteria

• Structural adequacy of the tested feature

• Occupant risk

• Vehicle trajectory after impact

Barrier Structural Adequacy

• Any test vehicle must be contained and redirected

• Controlled deflection of the barrier is acceptable

Occupant Risk

• No penetration of the passenger compartment

• Passenger compartment should not be significantly deformed

• The 1800 lb and 4400-lb test vehicles must remain upright after collision

More Occupant Risks...

• Unrestrained Passenger Decelerations: – Under 9 m/sec (30 ft./sec) preferred– 12 m/sec (40 ft./sec) max

• Occupant deceleration over a 10 millisecond period:– Should not exceed 15 G’s– 20 G’s is allowable