Why Simulation? An Interesting Case Study 2016-01-1484

This paper presents an example application for vehicle dynamics simulation software. This example investigates the validity of the vehicle motion presented in the famous car chase scene from the 1968 movie Bullitt. In this car chase, a 1968 Ford Mustang, driven by Det. Frank Bullitt of the San Francisco Police Department, is chasing a criminal driving a 1968 Dodge Charger through the streets of the Russian Hill district of San Francisco. The purpose of the simulation was to reconstruct the chase scene to determine the level of realism in the movie, in terms of conformance to Newton’s Laws of motion. To produce the simulation, several city blocks of the pertinent area of the city were surveyed and exemplar vehicles were measured and inspected. Three-dimensional computer models of the scene and vehicles were built. The movie footage was analyzed to determine vehicle speeds and driver inputs. The event was then simulated using three-dimensional vehicle dynamics simulation software. The results of the simulation confirmed the vehicles could not have navigated through the course at the speeds shown in the movie. It was determined that the vehicles’ speeds in the movie were at least 20 percent faster than the actual speeds of the vehicles when they were driven down Russian Hill. The chase scene could be duplicated using animation software (as opposed to simulation software), but the vehicles’ speeds in the animation would be 20 percent or more too high, and the error could go undetected. This example demonstrates an important benefit of simulation, which requires adherence to the laws of physics, in the analysis of vehicle dynamics presentations.

This paper provides the details of the procedures and resulting simulations, as well as the basis for the above conclusions.