Horowitz and Morton frequently traveled together giving tandem simultaneous exhibitions where they would follow one another around the boards, alternating moves. On one trip they were involved in a car accident that took the life of Morton and left Horowitz with serious injuries. Hermann Helms gave a brief account of the accident in the American Chess Bulletin in the January-February 1940 edition.
On February 17, 1940 while traveling through Iowa, Horowitz and Morton were involved in a serious car accident while crossing Iowa on the return journey after a tour of the south and far west. Morton, driving the car, was killed outright in a collision with a truck and Horowitz, suffering a concussion and other injuries, was taken to St. Anthony's Hospital in Carroll, Iowa. Horowitz remained in the hospital for some time and his brother, Irving, went to Iowa to be with him while he was hospitalized. Horowitz had not recovered sufficiently to play in the 1940 US Championship.
According to the Des Moines Register, the accident happened on highway 30, about seven miles west of Carroll, Iowa, when a van, driven by Frank S. Robbins of Denver, Colorado, collided with the car in which Horowitz and Morton were traveling eastward.
Route 30 approximately 7 miles west of Carroll, Iowa as it appears today.