Passenger safety in real-life crash scenarios of mass transit buses

Abstract

Buses and coaches form a vital part of the national as well as city public transportation network. Buses are still one of the safest modes of transportation. Nevertheless, bus accidents resulting in passenger injuries and fatalities do occur. According to the Traffic Safety Facts statistical reports from 1999 to 2003, an average of 40 fatalities and 18,430 injuries of bus occupants occurred per year. These accidents involved normal vehicle impacts, such as head-on or rear-end collisions. In this thesis the crashworthiness of the passenger compartment in a mass transit bus is evaluated and interior design guidelines that will mitigate the fatalities and injuries of the occupants during a crash event are recommended. Computational modeling and crash sled testing are used to analyze the frontal, side and rear accident scenarios in the passenger compartment. This report includes the evaluation of occupant injury during three accident scenarios by validating numerical models through MADYMO and LSDYNA codes versus experimental sled tests using Federal Motor Vehicle Safety Standards (FMVSSs) 208 injury criteria. Interior components are evaluated against crashworthiness requirements from the FMVSS and the Standard Bus Procurement Guidelines (SBPG). The sled pulses were generated from validated bus model finite element (FE) simulations of critical real-crash scenarios for frontal, rear and side conditions. The validated numerical model was then subjected to parametric studies to analyze the influence of the current vehicle interior design parameters, e.g., Seat spacing, seat height, location etc. on passenger kinematics and biomechanical performance. This study was carried out through a Design of Experiments (DOE). Optimization studies were carried out to define new bus interior designs that would reduce or mitigate passenger injuries.