Research efforts on crashworthiness and safety assessment of paratransit buses were initiated and subsequently supported by the Florida Department of Transportation over the past ten years. They gradually evolved from computational mechanics feasibility studies using non-linear finite element (FE) methods to an industry standard implemented in the state of Florida in August 2007. Paratransit buses sold in Florida can now be evaluated for safety per the state standard based on either experimental testing or on rigorous computational mechanics analysis with validated FE models. Verification and validation (V&V) process is based on multi-scale laboratory testing including:​ material characterization, wall panel and connection tests, and testing of the entire bus. Validated FE models are subsequently used to provide a comprehensive safety assessment of the entire vehicle.

Two accident scenarios, identified as critical and dangerous by bus manufacturers and operators in the United States, are rollovers and side impacts. Rollover assessment for paratransit buses is based on a tilt table test. It was adopted for the Florida Standard from the UN-ECE Regulation 66 (R66) [1]. In addition, a side impact evaluation was introduced due to a significant segment of large SUVs and pickup trucks among all vehicles sold in the US. Penetration of the residual space is used as a failure criterion in both tests.

The computational track of the assessment program supported by the laboratory validation experiments is presented in the paper. A new method of safety margin assessment in the rollover test based on angular deformations of the bus cross section is introduced. The program has been well received and is now partially supported by the bus industry.