This research investigates factors that influence severity of speed-related crashes on mainline roadway segments, with a particular emphasis on comparing single-vehicle and multiple-vehicle incidents and distinguishing between crashes involving legal speed limit violations and those exceeding the maximum safe travel speed as determined by law enforcement. Additionally, it examines significant factors related to classifying a crash as exceeding the maximum safe travel speed. Using crash data from the Traffic Records Electronic Data System (TREDS) for Virginia for 2023, the research employs both Ordinal and Nominal Logistic Regression models for analysis. The findings reveal that higher vehicle speeds before a crash significantly increase crash severity level across all scenarios. Rain and snow/sleet weather conditions exhibit significant impacts on crash outcomes, with adverse conditions often leading to increased severity levels. Roadway characteristics in terms of presence of medians and road surface conditions, are also found to be significant, as are. the driver-related factors of age, safety equipment used, EMS transport after the crash, and vehicle type. The study's comparative analysis between single and multiple vehicles speeding crashes, as well as speeding beyond legal limits and exceeding maximum safe travel speed highlights the contextual differences in crash severity determinants. The findings on classifying crashes as exceeding maximum safe travel speed highlight conditions that influence this designation as well as factors that can lead to inconsistencies in that classification. For example, environmental conditions like rain or snow, certain crash types, and work zone crashes may result in subjective assessments rather than objective determinations. The research offers valuable insights for informing targeted road safety strategies within the Safe System framework – targeted at reducing the severity of speed-related crashes for mainline road segments. The findings support implementing comprehensive strategies that address the complex interplay of speed, road conditions, vehicle characteristics, and driver factors in mitigating crash severity. / Master of Science / This research explores how speeding affects the severity of car crashes, seeking to understand why some accidents are more dangerous than others. By analyzing crash data from Virginia in 2023, the study looks at different types of crash scenarios – those involving just one vehicle and those involving multiple vehicles – and examines how factors like weather, road conditions, vehicle and driver characteristics contribute to the seriousness of these crashes. The research compares crashes where drivers exceed the legal speed limit with those where they drive faster than is safe under the given road conditions. Additionally, it investigates key factors that potentially influence law enforcement at the scene to designate that a crash involves a driver exceeding the safest speed for road and traffic conditions. The findings show that driving at higher speeds before a crash significantly increases the chances of severe injuries or fatalities. The study indicates how weather conditions, design characteristics of roads, or the condition of the road surface, impact crash severity. Driver age and whether drivers were under the influence of alcohol or drugs, and whether vehicle safety equipment like seatbelts were used, are significant in determining the severity of a crash. The findings on classifying crashes as exceeding maximum safe travel speed highlight conditions that influence this designation as well as factors that can lead to inconsistencies in that classification. This research is important because it provides insights for improving road safety.