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For designing crash avoidance systems it is necessary to know the dynamic conditions that characterize the accidents. This paper examines the dynamic conditions that set apart safe from unsafe lane changes. They are determined on the basis of the relative distances and velocities between the vehicles at the time the lane change is initiated, and upon consideration of the geometry of the lane change path. The analysis provides means to quantify the significance of the errors of the measurements and estimations that the countermeasure system must carry out to achieve its goal. The discussion includes consideration of system's latency and reaction times of driver and vehicle, to compare them with the time between lane change initiation and the moment when the crash would occur. The paper considers possible different levels of capability for lane change countermeasure systems, and how they could be verified by tests without crash risk.

This paper evaluates statistically the variability of braking efficiency obtained with new, original equipment(OE) brake sets, installed successively in the same vehicle. The analysis separates the components of braking efficiency variability caused by: 1) production variability among brake sets (due to differences in materials, machining, and assembling); and 2) measuring errors (pertaining to the braking measurement methods and measuring personnel). The data were obtained using three different methods: torque wheels, a low speed roller dynamometer, and “Road Transducer Plates” (RTP). The data were taken after burnishing each new brake set according to the Federal Motor Vehicle Safety Standard No. 105. The most accurate results were provided by the torque wheel measurements conducted simultaneously on the four wheels. With this type of measurement, the variability of braking efficiency was due more to brake set differences than to measuring errors.

This paper presents a discussion on the functional form (based on a theoretical analysis) of a regression model for estimating the fuel economy of motor vehicles. The statistical analysis tests the data for heteroskedasticity, investigates the use of different combinations of explanatory variables, discusses multi-collinearity, and determines the elasticities of fuel economy with respect to the various explanatory variables. Also, the analysis shows that the regression model can be treated as a case of restricted coefficients. The results of the statistical analysis--mainly the high value of the corrected coefficient of determination, and the very high values of the test statistics of all the coefficients of the regression--indicate that the selected model is satisfactory for the population represented by the given data.

A program was undertaken to determine which retrofit methods are currently feasible for used cars, considering emission reduction effectiveness, cost, effects on vehicle performance, facilities, and labor skill required for retrofit installation, maintenance, and inspection. An extensive search was made for all sources of information on retrofit methods, developers, and producers. Eleven representative retrofit devices were actually tested in this project. A fleet of 20 used vehicles without factory installed exhaust control systems was used for testing the performance of the retrofit devices. The vehicles were tested first without a retrofit device to obtain a reference baseline, and then with retrofit device installed. Emission tests were conducted by the 1972 CVS Federal Test Procedure. Fuel consumption was also measured during the CVS test. Drivability tests were conducted by an Automobile Manufacturers Association procedure.

Research on charge stratification of spark ignition engines has been under way at the University of Rochester for some time. Most recently the successful propane burning engine previously reported before the SAE has been converted to liquid fuel operation. This paper discusses some of the problems involved in the conversion and presents the results of tests on the liquid fuel version of the engine.