The spiels go something like this... "Para su seguridad (for your safety), mantenga sus manos, brazos, pies y piernas dentro del vehicle (keep your arms, hands, feet and legs inside the vehicle) y cuide a sus pequenitos por favor (and watch over your little ones please), gracias (thank you)". "Mantanganse alejado de las puertas, por favor" means 'Stay away from the doors, please." 'Keep your (safety) seatbelts fastened' goes "abroche su cinturon de seguridad"
Hope that helps a bit (which translates into "espero que esto te ayude un poco").