The challenge of meeting the Corporate Average Fuel Economy (CAFE) standards of 2025 has led to major developments in thetransportation sector, among which is the attempt to utilize clean energy sources. To date, use of solar energy as an auxiliary source ofon-board fuel has not been extensively investigated. This paper is the first study at undertaking a comprehensive analysis of using solarenergy on-board by means of photovoltaic (PV) technologies to enhance automotive fuel economies, extend driving ranges, reducegreenhouse gas (GHG) emissions, and ensure better economic value of internal combustion engine (ICE) -based vehicles to meet CAFEstandards though 2025. This paper details and compares various aspects of hybrid solar electric vehicles with conventional ICE vehicles.Different driving locations, vehicle sizes, various driving patterns and different cost scenarios are used in order to enhance the currentunderstanding of the applicability and effectiveness of using on-board PV modules in individual automobiles and ensure an accuraterepresentation of driving conditions in all U.S states at any time. These times and location-dependent results obtained over a year show anincrease in the combined mile per gallon (MPG) at noon in the range of 2.9-9.5% for a vehicle similar to a Tesla S, and a significantincrease in the range of 10.7-42.2% for lightweight and aerodynamic efficient vehicles. In addition, by adding on-board PVs to cover lessthan 50% of the projected horizontal surface area of a typical mid-size vehicle (e.g., Toyota Camry or Nissan Leaf), up to 50% of totaldaily miles traveled by an average U.S. person could be driven by solar energy. Also, the return on investment (ROI) of adding PVson-board with ICE vehicle over its lifetime shows only negative values when the price of gasoline remains below $4.0 per gallon and thevehicle is driven in low-solar energy area (e.g., Boston, MA). The same ROI is more than 250% if the vehicle is driven in high-solarenergy area (e.g., Arizona), even if the gasoline price remains low. For future price scenarios, this ROI is much higher - nearly 10 times theinvestment cost under some scenarios, with the assumption of an eventual decline in battery costs. With regard to environmental impacts,significant gasoline gallons savings (~500-3400) and CO2 emission reduction (~5.0 to 34.0 short tons) are achieved.