Discription of Events: I was going 38mph in a 35mph zone on Stone Mill Drive toward Rt. 462. Driver appeared out of nowhere tailgating immediately. A green traffic light was less than one mile ahead. Driver behind me suddenly sped up and passed me on the left forcing drivers going the opposite direction to veer to their shoulder. In this time, the traffic light had turned red for over one second. Driver erratically stops. When said light turns green, the driver does not advance for several seconds. After a honk, Driver appears to look up and floor the gas pedal. Driver sped up very quickly until slamming on brakes when it met regular traffic going approximately 35mph. Speed limit here is 40mph. At this point the driver swerves left to right, outside of road lines. At this point I had caught up with the vehicle which was now tailgating the traffic in front of them. The driver then slammed on brakes and turned right into McDonald's at 1755 Columbia Ave., Lancaster. I pulled in after to photograph license plate for report. Looked like kids were getting picked up, as the driver also stopped halfway into the drive-thru lane with no signal or 4-ways. This is not the first time I have noticed this vehicle in this area. This is just the first time I have been able to get the plate.