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991.
J. Y. Wong R. R. Guntur 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1978,7(1):25-47
It is known that loss of directional stability during braking occurs in many road accidents involving tractor-semitrailers. To minimize the undesired directional response, the correct order of locking of the wheels is of importance and should receive greater attention. This paper examines the effects of operational and design parameters on the sequence of locking of the wheels of tractor-semitrailers. The way in which the correct locking sequence may be achieved is also discussed in detail. 相似文献
992.
Andrew M. Malecki 《Transportation》1978,7(4):403-415
The perception that drivers have of car operating costs is an important factor in determining modal split characteristics. Theoretical figures derived from discriminant analysis models suggest that drivers perceive only petrol costs, but this has not been cor roborated by detailed surveys. This report examines in detail perceived and actual journey to work petrol costs of a sample of London commuters. The perception is also examined of related factors, such as petrol consumption and distance, in an attempt to throw some light on the perception mechanism itself. 相似文献
993.
994.
M. J. H. Mogridge 《Transportation》1978,7(1):45-67
Since the oil crisis of 1973, a number of studies have been made in various countries of the effects of the rise in petrol prices on the level of traffic flow, but rather fewer have attempted to delineate the complex chain of reactions within the car market set off by this impulse. We attempt to do this, using data from the UK.Since 1966 during the prediction stage of the first London Transportation Study it became obvious that low income and high income households had different rates of growth of car ownership, mainly because low income households bought cheap, old cars which vary in quantity and price differently from expensive, new cars. The Greater London Council therefore sponsored a study of car prices by age and size, starting from 1957 annually, and since the oil crisis, evaluated monthly. This has enabled us to examine the strong change in trend that had occurred, with large cars depreciating 15% per annum more than the smallest. The quantities of cars of each size registered each month are available from national statistics and this enables us to say that the previous 1% per annum increase in car size was arrested, with new cars becoming substantially smaller.A model of the car market has been developed which relates on the one hand the price distribution of cars by age, and on the other hand the price. distribution of the stock of cars owned at each household income level. Via the expenditure on car purchase at each household income level and the distribution of the length of time between purchase and resale of cars, a fully dynamic model has been developed to relate expenditure flow and stock. This enables us to test the effect of different trends on the dynamic equilibrium in the car market.The implications of the two trends noted above on the prediction of future car ownership growth are discussed, with the standstill since the oil crisis attributed to petrol prices via the split in household expenditure between purchase and use. 相似文献
995.
R. B. Richardson 《Maritime Policy and Management》1977,4(4):203-208
Although considerable progress has recently been made in the evolution of marine traffic procedures in coastal and waterway areas, mariners are finding difficulty in coping with the diverse traffic schemes that have so far been devised. This paper is a plea for international and logical marine traffic management, so that ships can operate safely and efficiently within a framework of the proliferating offshore zonal legislation that we are now witnessing. 相似文献
996.
C. E. M. Pearce 《Transportation Research Part B: Methodological》1981,15(6):427-435
An analytical study is made of the determination of the travel intensity at an arbitrary point of a city with a straight line barrier. For a given origin and destination a trip is made by the shortest path not crossing the barrier or the city perimeter. The joint trip end distribution is arbitrary except for a continuity assumption. 相似文献
997.
998.
E. C. Mikulcik 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1980,9(5):281-289
The characteristic equation for a simple automobile-trailer combination is analyzed, revealing the parameter groups which are important in determining the stability characteristics. Application of Routh's method results in separate criteria for oscillatory and non-oscillatory criteria which can be evaluated algebraically, and which can also be displayed graphically showing a region of stability on a two-dimensional plot. The stability region is bounded by limits of oscillatory and non-oscillatory stability, and the evaluation of a specific case corresponds to the location of a point relative to the boundaries. 相似文献
999.
1000.
E. Esmailzadeh 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1978,7(2):83-96
The transmission of road-generated vibrations into a vehicle body is treated as a source-path-receiver problem. The suspension system acts as the path, and improved isolation can be achieved by having a single compliant bushing at the connecting point of the shock absorber to the body with none at the other end. A mathematical model is derived for such a system which would enable detailed parameter investigation to be undertaken using the gradient method of optimization. An expression for the absolute displacement transmissibility of the body is derived and the optimization procedure is applied in order to evaluate the optimum values of the non-dimensional variables involved. This minimizes the maximum motion transmitted to the body from the road surface over a broad frequency range. Design data which are presented non-dimensionally for parameter variations show the influence of three variables: the bushing stiffness, the resonant frequency ratio and the damping coefficient upon the transmissibility. 相似文献