I read that comment which is an interesting observation but it's just one person's opinion and it wasn't made by a Verified Insider or a verified expert of traveling around that area. According to Google Maps, the scooter rental place is about 55 miles from where her car was found which would take about an hour, and it is possible she was speeding whenever she could.
Also, we have the witness who supposedly picked her up at Keith Lane near the car crash site. LE has not revealed that person to be a POI or suspect and they haven't even revealed his name. It seems they have reason to believe this witness is telling the truth, OR they have a vested interest in not releasing any more info.
As far as I have read, no one has said what time Sheridan was dropped off at the fire station, which would be helpful info in establishing a timeline. It's strange so much info is missing. Why not say something like "The witness picked her up ~2:30 when he saw her running along Keith Lane. He dropped her off at the fire station around 3:15 into the custody of a fire officer." OR say "The witness picked her up ~2:30pm near the car crash site and dropped her off at the fire station. Unfortunately the witness wrongly assumed an officer would be present to help and did not wait to make sure Sheridan made it inside safely with a fire station employee. No employees were at the station until ___ but they did not see Sheridan at that time." Why didn't they say something like that? How would that info compromise the investigation? This is why I'm suspicious that there is some sort of cover-up.