Final answer:
Without specific data on young driver fatal crashes and speed limits, it is not possible to provide a percentage. Safety statistics generally outline accident rates by age group, speed limit, and other factors, with driver error being a significant contributor to fatal crashes.
Step-by-step explanation:
The student's question relates to the proportion of young driver fatal crashes occurring on roadways with speed limits of 55 MPH or less. To determine this, one would typically examine traffic safety statistics which are found in reports by governmental transportation agencies or auto safety organizations. Such statistics usually include rates of accidents by age group, speed limit, and other factors. If we take note of the fact that driver error is a contributing factor to over half of all fatal crashes, this could suggest a need for improved education and safety regulations for young drivers. It is important to consider the speed limit as well since it has a direct impact on the outcome of crashes. Unfortunately, without specific data or statistics, it is not possible to provide a numerical percentage. A more detailed study, like the hypothetical one noted, would be required to provide specific figures.