If you ever run out of gas or have a flat tire immediately note your mile marker and call #77 they will dispatch a Virginia Department of Transportation (VDoT) truck to give you gas or change a tire all for free. It’s about your safety so stay in the car and be safe. This goes for any major highway in Virginia.
List of service from VDOT (All services are FREE)
Tire change if you have a good spare and you must know where the lug lock is if you have one.
Water for over heated car but only water no coolant. 
Gas if you run out
Jumpstart for dead battery
Traffic control for accident scenes.
If you happen to have a cool driver they may have a cellphone cable you can use but that goes by the discretion of the VDOT driver. Put your hazards on VDOT is suppose to stop out with all vehicles they see but sometime they miss them. They are just making loops and will return.
Link to page for verification: https://www.virginiadot.org/travel/safetypatrol.asp