I haven't read all posts, so I apologize if the following has been mentioned.
Some extant solar roofs were engineered primarily for cabin ventilation, while parked in full sun, to reduce the air conditioning load if driven during daylight.
The limited PV conversion efficiency and small array size precluded any meaningful power capture. Small battery capacity precluded any meaningful storage capacity. Economics precluded the use of space-grade PVs of higher efficiencies.
Real efficiencies won't come until there's a complete moratorium on additional real estate development until after there's 100% traffic light synchronization, nationwide.
Around 1988, TEXDOT , alone, found that for every $1.00 not spent on traffic light synchronization, motorists were losing $ 67.00, according to the Texas Governor's Office.
