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This technical paper presents the results of full scale vehicle testing completed to examine deceleration on late model tractor semitrailer vehicles equipped with original equipment manufacturers (OEM) engine brakes. Testing consisted of measuring vehicle deceleration through a test section with the engine brake function both active and inactive. Also, rolling resistance measurements were taken to aid in the subject research project and also augment the body of available heavy truck deceleration data. Additionally, a comparison of the measured deceleration data to calculated values based on OEM supplied engine brake performance curves was completed. Results of the testing and research project indicate that theoretically calculated engine brake deceleration can be added to vehicle drive train resistance to arrive at an estimate of total vehicle deceleration.

Many reports and papers have been published discussing light bulb filament deformation including incandescent/non-incandescent bulbs at impact and hot shock versus cold shock. The focus of the present research is to evaluate impact pulse as it applies to the time relationship between energy application/deapplication and filament deformation in brake/signal light bulbs. Also, the deformation characteristics of average tail light, brake/signal light, marker light, and halogen bulbs were examined. The study will record filament behavior of these light bulbs during impacts produced by a pendulum impact apparatus. Results of the subject research indicate that filament deformation can be expected in a light bulb operating in flashing mode at the time it is impacted. Additionally, deformation characteristics of interchangeable light bulbs produced by different manufacturers showed widely varied results relative to filament deformation when subjected to similar impact pulses.

This paper presents the results of full scale vehicle testing completed to examine deceleration factors, or friction coefficients, on various off-road and on-road surfaces. Of particular interest is the relationship between vehicle side slip and deceleration rates on soft, off-road, deformable soils. Vehicle testing was conducted at slip angles of 0, 30, 45, 60, and 90 degrees with locked and unlocked wheels. A comparison of the experimental data is made with respect to the theoretical prediction of deceleration being trigonometrically related to slip angle. Results indicate the theoretical prediction as fairly approximate through a portion of the side slip range. As side slip angles approach 90 degrees, actual measured values are higher than predicted.