Story of the ghost truck

I had two very strange encounters traveling on the Baltimore Beltway (i695) to interstate 83 heading to Harrisburg PA at night. The exit for i83 is a left exit off the Beltway with a sharp “s” turn in it. It was about 10:30 pm the first time this happened and exactly 11:15 pm the second time.The two events are identical with the exception of the time of night. There were no vehicles behind me as I merged into the left lane to exit the Beltway. As I approached the exit ramp I slowed to 35 mph to navigate the ramp. I looked in my mirrors and saw truck headlights suddenly behind me. I looked ahead to watch the road for a second then looked in my mirror and saw the headlights right on my tail, very close. I looked forward again to take the next turn, braking slowly to back the driver off keeping an eye on my mirrors to see if I was going to be hit. I looked ahead again to start merging into traffic, but when I checked my mirror a third time the lights were GONE! I merged onto i83 with NOTHING behind me! what happened to the truck? The first time I saw this I remember thinking the driver must have slowed down or stopped on the ramp or something weird like that or maybe i was just tired and misunderstood what I saw. I didn’t put much more thought into it. But this last time I got the feeling of Deja Vu and had a clear account of what happened. The truck vanished! I am positive a Semi appeared out of nowhere behind me as i entered the ramp, then as i exited the ramp it was GONE!!!Tthere is only one lane in the ramp with no other possible exits. Where did this truck go? I’m still baffled at what I witnessed and a little freaked out. If it happens again I will have to say there is a Ghost Truck that drives the Baltimore Beltway exit ramp to interstate 83 at night.