C172 pilot reported on touchdown observing a vehicle on a converging taxiway not in communication as it crossed the hold short line resulted in the aircraft stopping to avoid a collision.

Narrative

I was coming in for a landing on Runway 06 at Potomac Airfield (VKX) at approximately XA45 on a clear calm morning. I flew a straight-in approach to Runway 06 as is the standard calm-wind procedure at the airport. I made calls at 8 miles; 5 miles; 3 miles and 1 mile from the runway stating my approach and location. No aircraft were in sight in the air or moving on the ground and there was no response on the radio.As I touched down on Runway 06; I saw a motor vehicle off my right side through my peripheral vision. The car was driving on a taxiway from the south side of the field towards Runway 06/24 (driving north on the taxiway). I considered going around but there wasn't enough room to accelerate; climb; and clear the vehicle. Therefore; I raised flaps and aggressively stepped on the brakes on the runway. The car saw me coming and stopped well past the hold short line just across the edge of the runway. I was able to stop the airplane just shy of the car on the runway and our separation on the ground was no greater than 20 feet. I taxied off the runway in the opposite direction of the car (towards the fuel tanks on the north side of the field). The car then drove around me and left the field speeding.The airport is a public access airport that is completely open to pedestrian and vehicular traffic; which contributes to the possibility of these types of runway incursions. I think there should be signage for drivers to stop before hold short lines and to look for approaching landing traffic before entering the runway. Alternatively; vehicular traffic could be controlled by adding gates to limit access to only vehicles with business at the airport (and subject to necessary training concerning proper airport procedures).This was a big scare that could have ended up with an accident but luckily everyone went home and both the airplane and vehicle involved were spared damage.