You will notice this is not the first test driver killed on this stretch of bahn. I used to drive this every day back and forth to work, from Rhein-Main to Weiderstadt in the late 70's early 80's. (Mustang 5.0). There is a memorial to Bernd Rosemeyer, who was killed testing an Auto Union in the '30's, on this stretch. Here is an excert from an article about the incident. It may explain why the other test drivers seem drawn to this piece of road.
"the end of the season Mercedes feeling that their reputation was taking a beating by the upstart Auto Union team and its brash driver decided to undertake an attempt to regain the land speed record from Auto Union. The attempt would take place on the Frankfurt-Darmstadt-Heidelberg autobahn.
Rosemeyer in describing his record setting run stated that
"... at about 240 mph the joints in the concrete road surface are felt like blows, setting up a corresponding resonance through the car, but this disappears at a greater speed. Passing under bridges the driver receives a terrific blow to the chest, because the car is pushing air aside, which is trapped by the bridge. When you go under a bridge, for a split second the engine noise completely disappears and then returns like a thunderclap when you are through.
They set the date of their attempt for the end of January prior to the Berlin Automobile Show. Auto Union could not ignore the publicity that Mercedes would gain from this feat and decided to be prepared just in case.

On January 27, 1938
Alfred Neubauer checked with the weather bureau at the Frankfurt Airport and learned that the conditions would be ideal the next morning but that the wind would pick-up after 9:00 a.m. At eight Caracciola was off and the record at 268 mph belonged to the three pointed star. "I was unnerved," Caracciola would say.
"The road seemed like a narrow white band, the bridges like tiny black holes ahead. It was a matter of threading the car through them..." Rosemeyer was one of the first to congratulate Caracciola and said,
"My turn now." Caracciola, aware of the prediction for strong winds sought to warn his young rival but was assured by Rosemeyer that he was one of the
"lucky ones." Just before noon Rosemeyer entered the closed cockpit special and rocketed down the Autobahn. Traveling at over 270 mph a crosswind caught his car and caused the Auto Union to somersault flinging Rosemeyer to his death. Neubauer, Caracciola and von Brauchitsch, his Mercedes rivals, sat silently for a long time,
"unmoving like statues," in Caracciola's words. Record breaking was over for now. "
Bernd literally did not know fear", Rudolf Caracciola said of his great rival,
"and sometimes that is not good. We actually feared for him in every race. Somehow I never thought a long life was on the cards for him. He was bound to get it sooner or later..."
Bernd Rosemeyer was buried with full military honors. Hitler said to the German nation
"May the thought that he fell fighting for Germany's reputation lessen your grief."
