Commercial Vehicle TestingWyoming Law Enforcement Academy

June 17, 2004

Conducted by:John & Jeremy Daily

Jackson Hole Scientific Investigations, Inc.Nate Shigemura

The Traffic Safety Group

Commercial Vehicle Testing

• Two Tractor-Semi-trailer combinations were tested on June 17, 2004 at the Douglas Raceway in Douglas, WY.

• Tests included:– Braking Performance– Acceleration– Lane change lateral g– Yaw rate of Tractor in lane change– Jake Brake performance

Commercial Vehicle Testing

• Test Unit #1:– Freightliner Model TT (1991)– Raven 40 foot flatbed trailer– Total Combination Weight: 28000 lbs

• Test Unit #2:– Kenworth Model T-800 (1991)– Great Dane 48 foot Flatbed Trailer– Total Combination Weight: 34,250 lbs

Freightliner Tested

Kenworth Tested

Test Conditions

• Test Track was run-out portion of a drag strip.– Average µ ranged between 0.80 and 0.83– Weather was overcast with occasional rain

showers– Surface was chip-seal and the minimal

moisture had no measurable effect on the friction values

– Temperature was in the low 50’s and winds were calm to light.

Instrumentation

• The Tractor units were instrumented with a VC-3000 accelerometer– The accelerometer served as a DAQ for a rate gyro– The accelerometer was mounted on the passenger

side step, along with the rate gyro• A DRMS paintball gun was used as a shot

marker to determine overall stopping distance– This unit was clamped to the front bumper– It was energized by a tape switch on the treadle valve

pedal

Accelerometer Installation

Rate Gyro Installation

DRMS Shot Marker

Tape Switch

Downloading Data

Data Graphs

• The test results are presented in the following graphs:

Time 87.98 to 91.01

Freight Li 6/17/2004 1

Avg Acceleration -0.471gfedcbAvg Speed 22.950gfedcAvg Distance 3,563.072gfedcAvg Lat Accel 0.035gfedcAvg Rate Gyro 1.484gfedc

Freightliner Full Braking- No Axle #4 - Test #1Calculated Deceleration Factor = -0.48

Measured Decelration = -0.471 G

Time (Sec.)9493929190898887868584

Acc

eler

atio

n (G

)

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

Time 50.82 to 53.93

FreightLin 6/17/2004 2

Avg Acceleration -0.473gfedcbAvg Speed 12.551gfedcAvg Distance 1,597.024gfedcAvg Lat Accel 0.047gfedcAvg Rate Gyro 2.134gfedc

Freightliner: Full Braking - Test #2Calculated Deceleration Factor = -0.48Measured Deceleration Factor = -0.473

Time (Sec.)55545352515049

Acc

eler

atio

n (G

)

0.30

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

Time 52.58 to 57.02

FreightLin 6/17/2004 3

Avg Acceleration -0.195gfedcbAvg Speed 5.732gfedcAvg Distance 1,313.898gfedcAvg Lat Accel -0.025gfedcAvg Rate Gyro 0.383gfedc

Freightliner with Spring Brakes Only - Test #3No Calculated Drag Factor

Measured Deceleration = -0.195

Time (Sec.)5958575655545352515049

Acc

eler

atio

n (G

)

0.30

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

Time 40.88 to 43.33

FreightLin 6/17/2004 4

Avg Acceleration -0.526gfedcbAvg Speed 13.216gfedcAvg Distance 1,143.508gfedcAvg Lat Accel -0.004gfedcAvg Rate Gyro 0.956gfedc

Freightliner Bobtail Computed Deceleration Factor = -0.54

Measured Deceleration = -0.526 G

Time (Sec.)45444342414039

Acc

eler

atio

n (G

)

0.30

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

-0.60

Time 69.68 to 72.49

Kenworth 6/17/2004 5

Avg Acceleration -0.452gfedcbAvg Speed 18.566gfedcAvg Distance 2,649.470gfedcAvg Lat Accel -0.012gfedcAvg Rate Gyro 0.093gfedc

Kenworth: Brakes out of Adjustment - Test #5Calculated Deceleration Factor = -0.57Measured Deceleration Factor = -0.452

Time (Sec.)75747372717069686766

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

Time 49.19 to 51.79

Kenworth 6/17/2004 6

Avg Acceleration -0.560gfedcbAvg Speed 15.486gfedcAvg Distance 1,575.687gfedcAvg Lat Accel -0.012gfedcAvg Rate Gyro -0.808gfedc

Kenworth- with all brakes adjusted and workingComputed Deceleration Factor = 0.56

Measured Deceleration = -0.56 G

Time (Sec.)5554535251504948474645

Acc

eler

atio

n (G

)

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

-0.60

Time 84.48 to 85.57

Kenworth 6/17/2004 7

Avg Acceleration -0.454gfedcbAvg Speed 10.216gfedcAvg Distance 2,793.499gfedcAvg Lat Accel 0.003gfedcAvg Rate Gyro 0.082gfedc

Kenworth: Spring Brake Application - Test # 7No Calculated Brake Forces

Type 30/30 Chambers on Axles 2, 3, 4 & 5Measured Deceleration from Spring brakes = -0.453 G

Time (Sec.)90898887868584838281807978777675

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

Time 95.50 to 102.97

Kenworth 6/17/2004 8

Avg Acceleration -0.160gfedcbAvg Speed 28.091gfedcAvg Distance 4,504.275gfedcAvg Lat Accel 0.003gfedcAvg Rate Gyro 0.009gfedc

Kenworth: Trailer braking only (Hand Valve) - Test #8Calculated Deceleration Factor = -0.17

Measured Deceleration Factor = -0.160 G

Time (Sec.)106105104103102101100999897969594939291

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

Time 49.50 to 53.00

Kenworth 6/17/2004 9

Avg Acceleration -0.378gfedcbAvg Speed 12.543gfedcAvg Distance 1,482.572gfedcAvg Lat Accel -0.035gfedcAvg Rate Gyro -1.140gfedc

Kenworth: Tractor Braking Only - Test #9Calculated Deceleration Factor = -0.39

Measured Deceleration = -0.378

Time (Sec.)5655545352515049484746

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

Time 67.74 to 70.71

Kenworth 6/17/2004 10

Avg Acceleration -0.500gfedcbAvg Speed 22.451gfedcAvg Distance 3,079.925gfedcAvg Lat Accel 0.036gfedcAvg Rate Gyro 0.731gfedc

Kenworth: Bobtail Full Braking - Test #10Calculated Deceleration Factor = -0.53

Measured Deceleration = -0.500

Time (Sec.)7473727170696867666564

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

-0.30

-0.40

-0.50

Time 52.38 to 55.17

Freight Li 6/17/2004 1

Avg Acceleration 0.016gfedcAvg Speed 34.785gfedcAvg Distance 1,568.127gfedcAvg Lat Accel -0.083gfedcbAvg Rate Gyro -3.183gfedc

Freightliner: Normal Lane Change - Test #1

Time (Sec.)6059585756555453525150

Lat A

ccel

(G)

0.10

0.00

-0.10

Time 29.38 to 31.70

FreightLin 6/17/2004 2

Avg Acceleration 0.028gfedcAvg Speed 30.792gfedcAvg Distance 599.280gfedcAvg Lat Accel -0.213gfedcbAvg Rate Gyro -7.801gfedc

Freightliner: Aggressive Lane Change - Test #2

Time (Sec.)3534333231302928

Lat A

ccel

(G)

0.40

0.30

0.20

0.10

0.00

-0.10

-0.20

-0.30

Time 26.92 to 28.96

FreightLin 6/17/2004 3

Avg Acceleration -0.013gfedcAvg Speed 22.541gfedcAvg Distance 433.572gfedcAvg Lat Accel 0.145gfedcbAvg Rate Gyro 6.392gfedc

Freightliner: Normal Lane Change - Test #3

Time (Sec.)333231302928272625

Lat A

ccel

(G)

0.20

0.10

0.00

-0.10

Time 22.78 to 24.45

FreightLin 6/17/2004 4

Avg Acceleration 0.049gfedcAvg Speed 28.629gfedcAvg Distance 379.816gfedcAvg Lat Accel -0.157gfedcbAvg Rate Gyro -5.990gfedc

Freightliner Bobtail Lane Change-Test #4

Time (Sec.)28272625242322

Lat A

ccel

(G)

0.20

0.10

0.00

-0.10

-0.20

Time 30.90 to 33.22

Kenworth 6/17/2004 5

Avg Acceleration 0.079gfedcAvg Speed 34.465gfedcAvg Distance 678.376gfedcAvg Lat Accel 0.159gfedcbAvg Rate Gyro 5.069gfedc

Kenworth: Aggressive Lane Change - Test #5

Time (Sec.)38373635343332313029

Lat A

ccel

(G)

0.30

0.20

0.10

0.00

-0.10

-0.20

Time 24.15 to 26.29

Kenworth 6/17/2004 6

Avg Acceleration 0.082gfedcAvg Speed 24.271gfedcAvg Distance 409.229gfedcAvg Lat Accel 0.188gfedcbAvg Rate Gyro 7.487gfedc

Kenworth: Aggressive Lane Change - Test #6

Time (Sec.)3029282726252423

Lat A

ccel

(G)

0.30

0.20

0.10

0.00

-0.10

-0.20

-0.30

Time 46.49 to 49.82

Kenworth 6/17/2004 7

Avg Acceleration 0.110gfedcAvg Speed 25.429gfedcAvg Distance 921.751gfedcAvg Lat Accel 0.044gfedcbAvg Rate Gyro 2.202gfedc

Kenworth: Double Normal Lane Change - Test # 7

Time (Sec.)6560555045

Lat A

ccel

(G)

0.00

-0.10

Time 50.92 to 54.45

Kenworth 6/17/2004 8

Avg Acceleration 0.049gfedcAvg Speed 39.304gfedcAvg Distance 1,788.798gfedcAvg Lat Accel 0.067gfedcbAvg Rate Gyro 1.981gfedc

Kenworth: Double Normal Lane Change - Test #8

Time (Sec.)7065605550

Lat A

ccel

(G)

0.10

0.00

-0.10

Time 33.75 to 36.48

Kenworth 6/17/2004 10

Avg Acceleration 0.047gfedcAvg Speed 32.370gfedcAvg Distance 1,201.578gfedcAvg Lat Accel 0.119gfedcbAvg Rate Gyro 4.199gfedc

Kenworth: Bobtail Double Normal Lane Change - Test #10

Time (Sec.)5045403530

Lat A

ccel

(G)

0.10

0.00

-0.10

Time 39.29 to 45.34

Kenworth 6/17/2004 8

Avg Acceleration -0.092gfedcbAvg Speed 33.965gfedcAvg Distance 1,292.022gfedcAvg Lat Accel -0.004gfedcAvg Rate Gyro -0.047gfedc

Kenworth: Acceleration and Jake Brake - Test #8

Time (Sec.)45403530252015105

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

Time 37.52 to 42.77

Kenworth 6/17/2004 7

Avg Acceleration -0.102gfedcbAvg Speed 22.033gfedcAvg Distance 690.083gfedcAvg Lat Accel -0.009gfedcAvg Rate Gyro -0.026gfedc

Kenworth: Acceleration and Jake Brake - Test # 7

Time (Sec.)40353025201510

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20

Time 26.82 to 32.31

Kenworth 6/17/2004 10

Avg Acceleration -0.104gfedcbAvg Speed 36.697gfedcAvg Distance 934.187gfedcAvg Lat Accel 0.004gfedcAvg Rate Gyro 0.043gfedc

Kenworth: Bobtail Acceleration and Jake Brake - Test #10

Time (Sec.)30252015105

Acc

eler

atio

n (G

)

0.20

0.10

0.00

-0.10

-0.20