Bus dynamics for mobility-aid securement design

Abstract

Mobility-aid securement on large urban transit buses has been designed without an adequate knowledge of either the accelerations that are likely to occur in normal operations or the maximum accelerations that are possible short of an impact accident. These normal operation accelerations are important because they are the source of motion and corresponding sense of insecurity on the part of the passenger when riding in a mobility-aid on a bus. This paper describes the equipment and procedures used to measure the distribution of accelerations to be expected on large buses in normal transit service and the maximum accelerations possible during extreme maneuvering for six different sizes and types of transit buses. Included in the tests were low-floor buses of different lengths, a high-floor bus, a 40-ft (12.2-m) low-floor double-decker bus, and a 60-ft (18.3-m) low-floor articulated bus. During in-service tests, the accelerations were generally a function of the driver. In maneuvering tests, the mechanics of the bus design were the controlling factors. The results show that, in general, normal driving accelerations were typically less than 0.2 g in all directions and very rarely greater than 0.4 g. In the event of an emergency-driving situation, forward and turning accelerations may reach 0.4 g and stopping may result in 0.8 g. © 2007 Taylor and Francis Group, LLC.