Traffic quickly took a heavy toll on the planks. Battered by the passing cars of tourists and farmers, the road was splintered further by maintenance crews who uncovered the wooden road with mule drawn scrapers to clear it of drifting sand. Still, Fletcher and Boyd had proved that a road was feasible, and motorists had demonstrated the necessity for a good road. In June 1915, the California State Highway Commission assumed responsibility for the Plank Road as part of the road system linking Southern California with Arizona.
With more funds, the Highway Commission built a new Plank Road in 1916. Engineers abandoned the double-track plan and designed a roadway of wooden cross ties laid to a width of 8 feet with double-width turnouts every 1,000 feet.
Plank Road upkeep proved difficult. From 1916 to 1926, crews of workmen struggled incessantly against nature to keep the road passable. Hard winds blew drifting sand across the road an average of two or three days a week, rendering the road nearly impassable about one-third of the time.
Crossing the Plank Road was both an adventure and a trial. Pulling off the road onto the turnouts so that others might pass tried the patience of motorists. Traffic jams in the midst of desert vastness were not uncommon. On one occasion, a caravan of 20 cars encountered a lone traveler going in the opposite direction. Whether through timidity or stubbornness, the driver refused to back up to a turnout behind him. Finally, the party took matters in hand. The men lifted the car and set it on the sand, while the women proceeded to advance the caravan. When they were past, the car was lifted back up on the road, and all continued on their way. Turnouts along the Plank Road were marked with old tires mounted on high posts to make them visible from afar.
Despite the discomfort and outright danger of crossing the Plank Road, former travelers still recall with amusement the feeling of high adventure that was part of the Plank Road experience. While the road opened up a valuable trade route for Imperial Valley farmers and townsfolk, riding across it also became a favorite winter recreational activity. In fact, desert parties were so popular that Gray's Well usually resembled a campground during the winter months. Newt Gray obliged travelers and desert party groups alike by stocking a small, tin roofed store with emergency provisions and cold drinks.
The days of the Plank Road were numbered. The twin headaches of maintenance and traffic flow required a better solution. In 1924 the Commission tested a new, improved Plank Road which would permit two-way traffic to cross the dunes. In addition, from 1923 to 1925, engineers monitored the movement of sand dunes adjacent to the Plank Road and tested various surfaces. After concluding that hills of sand over 100 feet high moved very slowly and only the lower dunes moved rapidly, it was determined that a permanent road was indeed possible providing the grade was sufficiently raised.
With an engineering solution at hand, the Highway Commission decided on an asphaltic concrete surface constructed on top of a built-up sand embankment. The new road, 20 feet wide, officially opened on August 12, 1926. Praise for the highway was mixed with a certain nostalgia for the primitive wooden contraption it replaced. After all, the Plank Road had added a bit of spice to life in the Imperial Valley.
In recognition of the Plank Road's stature as an important historic example of transportation technology, the State of California designated its ruins as a California Historical Landmark. Portions of the road also are considered eligible for inclusion in the National Register of Historic Places.
Remnants of the Plank Road may be seen at the west end of Grays Well Road, the frontage road south of Interstate 8. A Plank Road monument and interpretive display lie approximately three miles west of the Sand Hills interchange.