It probably started as a foot path, then progressively improved.
The 39-mile roadway was first constructed between 1916 and 1922, and served as the main Kona-Waimea connector for 11-years until it was superseded by construction of the Māmalahoa Highway (now Highway 190) in 1933. (ASM)
Using prison labor, they built the road setting rocks, rolling with a steam roller, and pouring tar heated in a pot. A camp for the prisoners who built the road was located on the down slope side of the Saddle Road intersection, where a grove of eucalyptus trees stands today.
From Pu‘uanahulu south to Pu‘u Wa‘awa‘a, the road was built under the direction of Eben Low, by prisoners living at a camp located downslope of the road, at Ke‘enaki, at the 18-mile marker.
Then, the Waimea-Kona road was rebuilt and straightened, in the area down slope from the Ke‘amuku Sheep Station, by contractor Medeiros, leaving the old road to the east. (HDOT)
“The formal opening of the new belt road on the island of Hawaii, July 22, 1933, was an important occasion, attended by the Governor and his party from Honolulu and many excursionists.”
“The proposal has been made that the new road be named ‘Mamalahoe,’ commemorating the famous edict by King Kamehameha I, “the Law of the Splintered Paddle” making Hawaii’s highways safe for the traveler.”
“The earlier Hawaiians traveled along the rough and rocky trails from Kailua to Kawaihae assured of the protection of ‘Mamalahoe Kanawai.’ The old and the young alike were protected by this order of the king, Kamehameha.”
“Later on, the rough road was put through the lava fields and sufficed for a time until the demands of the new era have now been met by the highway dedicated only yesterday.”
“As we journey along this new road, let us think of the just and kind law enunciated by the ‘ali‘i nui.’ Kamehameha, Ka Nui Aupuni.”
“The opening of the Mamalahoe Road yesterday afternoon, named in honor of the beneficent law given by the great King Kamehameha, recalls to us the words of the ancient prophet Isaiah, as uttered in the fortieth chapter of that book, verse 3 – ‘Prepare ye the way of the Lord, make straight in the desert a highway for our God.’”
“In a literal sense, what has just been completed in North Kona was to make straight in that desert land, through lava flows and over rough places, a highway for all people who wish to make the journey around the Island of Hawaii or who desire to travel from Waimea to this fair land of Kona.”
“Across that desert-land many travelers have made their weary way, first on horses or in wagons from the more settled portions of North Kona, across the lava flow of 1801 and beyond Puuanahulu to the pastures near Waimea …”
“… and then in later years have journeyed in automobiles, an experience hard on the nerves of the driver and always hard on the tires of the car, making the trip an unwelcome one.”
“All these unpleasant features of travel on this island are now to be relegated to memory’s halls, for today we are now able to motor through the interesting upland country on a well-built highway made straight across the desert.”
“Thanks to the government in its various branches for the thoughtfulness and wisdom and care with which the project was completed, we would render today. The construction of this splendid road brings us in Kona nearer to the rest of the island and makes us feel more neighborly than ever before to others who live on this ‘Hawaii nui o Keawe.’”
“As never before, the charms and delightful spot! of this favorite land will be opened up to the world. For Kona has many “pana”—-many places famed in tradition and history, renowned in song and story.” (The Friend, July 1933)
EE Black, a contractor, built the road from Kailua-Kona to what is now the start of the Saddle Road. He used the first bulldozer in the history of the islands to do so. (Thurston)
This is what is now generally referred to as the ‘upper’ road between Waimea and Kona. The ‘lower’ road, Queen Ka‘ahumanu Highway, was built from Kailua to the ‘new’ Kona Airport in 1970 (when the new airport opened.) That road was completed to Kawaihae in 1975.
The improvement of the Waimea-Kona Road also played a role in the revival of outrigger canoe racing; but that is another story.