The necessity for avoiding the occupant ejection from their seats during motor coach rollover accidents is of supreme importance. The seat belt as a safety device is the best practical way of achieving this task. As per the motorcoach Enhanced Safety Act of 2009 passed in the United States senate, requires new motorcoaches to be installed with safety belts for each seating position. This bill also suggests the possibility of retrofitting seat belts on the existing motorcoaches. The use of portable seatbelt to restraint occupant is more economical as compared to retrofit the seat belt. This fact motivates the further research on portable restraint device. This paper demonstrates the evaluation of the first version of the Portable Restraint Device (PRD) using full scale bus rollover test. This test identified the shortcoming of this current device in securing to the bus seat and its non user friendly design. The computational technique is used to devise a new design of PRD with three point restraint system. This design concept is evaluated using computational method to identify the interaction of the restraint shoulder strap with the occupant neck. The new design of the portable restraint is presented in this paper based on the understanding of full scale test result and the computational analysis. The new design of the PRD is sleek and more user friendly.