Research was conducted to develop a post model for light-posts located near the edge of the traffic lane that, upon impact will be knocked out of the vehicles path and also will not land on the highway causing an unsafe condition for other motorists. It was designed to: (1) establish an analytical model that will describe the motion of a rigid body under the influence of gravity and time dependent forces, (2) apply numerical integration techniques to obtain a solution to the equations of motion, (3) investigate the stability of the numerical solution, and (4) attempt to correlate theoretical results with experimental data obtained from the impact of a vehicle on sign and light post systems. The correlation of the mathematical model with data obtained from a full-scale crash test demonstrates the feasibility of the application of the model to the luminaire support pole problem. Even though a case exhibiting planer motion was chosen for the correlation, the model also verified the phenomenological behaviour for the non-planer motion case of a vehicle striking a luminaire support. With the model simulating a true physical situation, studies can be conducted to evaluate the hazard potential of existing and proposed designs. Parameter studies can be made of promising designs, and these designs can be investigated to determine the response of the post to a variety of conditions. The effect of such variables as pole weight, pole weight per unit length, length of luminaire arm, weight of luminaire, weight of base assembly, weight and speed of impacting vehicle, and angle of attack of impacting vehicle can be investigated. The development is presented of the equations of motion and all equations for the mathematical model. It is concluded that the model can prove invaluable in reducing the number of full-scale crash tests required to develop and evaluate a particular design.
Abstract