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Braking deceleration values in units of gravity on ice surfaces have typically applied to the locked and sliding wheel with a representative friction coefficient of 0.10 ascribed. Three years of testing winter roads for traction and braking capacities and controlled tests on an ice arena show that large percentage variations exist in friction values. The term ‘ice surface’ and its attributes is not well defined in the literature. Tests were run using different tires, at different temperatures, with and without ABS on smooth and rough ice surfaces and tabulated to show the differences in braking deceleration. The locked wheel values were compared with those values normally used by accident reconstructionists and indicate that care must be taken in selecting a representative value.

Traction tests were run during February, 1993 and 1994. The snow tests were conducted at a fairly constant temperature of -2°C and the ice tests at an air temperatures ranging from -4 to -35°C. The test vehicles were a standard midsize automobile and highway maintenance gravel trucks. The automobiles on packed snow at -6°C has an average braking force coefficient of 0.35, a lateral force coefficient of 0.38 and a traction force coefficient of 0.20. The corresponding values for a straight truck are: 0.23, 0.35 and 0.15. An automobile on bare ice at -6°C has an average braking force coefficient and lateral force coefficient of 0.09, and a traction force coefficient of about 0.08. The valves for the truck on bare ice in the same order are 0.06, 0.07 and about 0.04. A relationship was developed between the average braking force coefficient, ambient temperature and the amount of standard highway winter aggregate used on the road.

Automobile hydroplaning speed is affected by both the vehicle load on the tire and its inflation pressure, yet only inflation pressure is used in Horne's (1968) equation. He later (1984) made modifications to include a vehicle's tire footprint characteristics. Dunlap et al. (1974) studied the influence of water depth and tread depth on an automibile's hydroplaning speed. Empirical studies by Gallaway et al (1979) produced more conclusive hydroplaning speeds for both automobiles and Ivey et al (1984) for trucks. This paper uses an influence diagram to show how all the models are related. Using the model the author pursues a few vehicle design parameters that may be combined to make vehicles more prone to hydroplaning. Also, a set of rules is suggested that may be used during accident reconstruction to determine if a vehicle has in fact hydroplaned and the potential source.

A low cost and low speed automobile crash test facility for full frontal impacts has been designed and constructed to determine vehicle crush characteristics. The function and operation of systems comprising the facility are discussed in this paper and include: Site layout and tow system arrangement Tow system and test vehicle guidance Crash barrier Release mechanisms Speed measurement Recording of the impact event In addition, the crash barrier is validated with preliminary test results.

Currently, there are very little data on the maximum crush experienced by vehicles during impact. Measurements of the maximum crush were made on selected vehicles to provide some insight on the amount of maximum crush during a collision and the extent of elastic rebound. Fourteen low speed barrier impacts were conducted at the Insurance Corporation of British Columbia and University of British Columbia (ICBC-UBC) test facility. In addition twelve measurements of maximum crush were obtained from Transport Canada high speed motion films of 30 mph impacts. To bolster the data, a paper by Hight provided thirty-three maximum crush measurements at impact speeds of 35 mph and one test at 40 mph. The combined data provided maximum crush information over a wide spectrum of impact speeds. The elastic crush which is the difference between maximum and residual crush was also determined. The amount of elastic crush on vehicles and the variation of elastic crush with residual crush was examined.

Increased awareness of road safety and a need for estimating vehicle speeds in accident reconstruction has spawned an ever increasing literature on speed estimation from vehicle damage. The theory used was quite simple and robust when first introduced in the early 1970s. The push of legislated fuel economy has produced a fleet of smaller and lighter cars which are structurally different from the vehicles of the early 1970s. The changing vehicle structure among other factors has reduced the robustness of the early analytical models introduced by Campbell (1972) and McHenry (1974). This paper goes back to a single variable, the slope of the impact speed/residual crush curve and derives a set of crush coefficients and their variance.