Oakland used to brag about the quality of its streets, which were made of Oakland rock. Two things, an accident of geology and technological happenstance, meant our first roads were built starting around 1860 with macadam paving, the pre-asphalt method of constructing roadways with layers of clean, sterile crushed rock, each layer wetted down and compacted under heavy rollers.

The geologic accident was the way the Hayward fault uplifted a body of decent bedrock and brought it north, one earthquake at a time, to where it sits today beneath the town of Piedmont. Luckily, the best of this material was just an hour up Broadway by horse and wagon in a rock quarry opened in the early 1860s by Horace Whitmore. Another two dozen quarries followed over the next century.

The state of technology in the 1860s made macadam a cheap and simple method at a time of great commercial need as the transcontinental railroad arrived and boom times followed. The causes included Alfred Nobel’s invention of dynamite, the development of efficient rock crushers and the spread of railroads to all elements of civilization. In addition, cheap immigrant labor in the quarries and competitive bidding for public construction projects helped Oakland leverage its advantage in crushed rock to mushroom into a logistical giant, combining trade by land and sea into a major node of American commerce.

For the next forty years, Oakland expanded across the flats and into the hills using local crushed rock for its new macadam streets. For the next forty years after that, Oakland replaced it all with asphalt. No macadam street is left today, except maybe this one segment along Courtland Creek.

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Unlike dirt or gravel, macadam roads didn’t turn to mud in the rain. They treated boots and horse hooves well, and they held up under ordinary traffic without complaint. Given cheap good rock and cheap unskilled labor, they were economical to build under stringent city budgets. Newly laid macadam was celebrated for the smoothness and quietness of its ride.

The maintenance costs of macadam roads, though, steadily accumulated. The most important, and notorious, was the cost of sprinkling the streets. That was part of the deal, because water helped hold the road together and because the topping of rock dust blew loose during the dry summer months. The water cost as much as the sprinklers’ wages.

In 1872, early in the macadam period, Oakland mayor Nathan W. Spaulding asked the City Council to do something: “Macadamized roadways require constant and unremitting attention, and this attention should commence from the moment the work is delivered by the contractor; no one thing will add more to their durability and improve their condition than the sprinkling of them during the summer season. I trust that you will inaugurate some system by which the streets that have been macadamized may be kept sprinkled; it will be a great saving to the property-owners as well as a convenience to the public.” He’d made similar, less pointed remarks the year before. Soon the city was a major customer of the city’s early private water companies.

Another cumulative problem was the cost of repairs. Once a street was disturbed to work on a sewer line or water main, it was not always rebuilt to its original condition. In a typical example (familiar to this day), the Tribune complained, “Recently Eleventh street, east from Broadway, was torn up by the Contra Costa Water Company . . . . The earth was then thrown back loosely and no attempt was made to put the street in as good condition as before. The course of the pipe can easily be traced by the surface of the street. On Ninetheenth street a similar piece of vandalism was committed. The street had been but recently macadamized — the roller had just been taken off and the street left smooth — when the same water company came along and put in pipe, leaving the street in a horrible condition, almost impassable.”

Today streets are made of asphalt, usually with concrete underneath. The change from macadam to asphalt took a long time, with intermediate stages. It began in the 1880s with the next advance in paving: bitumenizing, which meant using bitumen instead of water to bind the road material. “Bitumen,” especially in this country, means more to geologists than the general public.

Bitumen in geology means a natural fluid of organic material, everything from crude oil to natural asphalt. Geologists have names for a wide range of bitumens or mineral resins, including elaterite (“mineral rubber”), hatchettine (“mineral tallow”) and ozocerite (“mineral wax”). In the 1800s, though, it came in the form of natural asphalt or as coal tar, a byproduct of making “town gas” from coal. Bitumen-based pavement was expensive, reserved for the most demanding uses, but it lasted much longer than macadam and needed no sprinkling.

Bay area cities at first used bitumen from quarries in the Santa Cruz Mountains, supplied by companies like the Santa Cruz Rock Pavement Company. I’ve seen the raw stuff in an old mine site east of Davenport.

The move to bitumen began slowly. By 1890, Oakland had about one mile of bitumenized streets, and while the newfangled material didn’t need sprinkling, it still got dirty. That year the city authorized a $39 contract to sweep it eight times a month. “This will be the first time that any of the streets of Oakland have been swept,” the Tribune reported, “the clearing heretofore being confined to patches done here and there by individual enterprise and the occasional efforts of the chain gang.” By the end of 1896 Oakland had just five miles of bitumenized streets.

With the twentieth century the petroleum-and-automobile revolution changed everything. Oil was plentiful enough to use in new “oiled macadam” and to retrofit existing macadam streets. As of 1903 it was “now coming to the fore as a road-protector against rain,” and in 1909 the whole of Claremont Avenue was oiled as an experiment. The next year the city’s new road commissioner ordered oiled macadam to replace the old macadam used everywhere in Oakland outside downtown. The real estate community praised it.

By 1919 over 400 miles of streets were either bitumenized or oiled macadam, and the residential development of Lakeshore Highlands could one-up its competitors by using “regulation asphalt street with a concrete base” in a new standard of luxury. Within a decade this form of asphalt became the default.

In the age of oil starting in the Roaring Twenties, the asphalt upgrade went on relentlessly, aided by the Works Progress Administration during the Depression and the burst of prosperity after World War II. Now we have asphalt streets everywhere.

This change in road-building has transformed Oakland’s groundwater. Whereas macadam lets rainfall soak through the roadbed into the soil, bitumen and asphalt seal off the ground surface. Rainfall now runs off the impervious roads into gutters and a whole city infrastructure that drains this “stormwater” directly to the Bay, bypassing the landscape and the cleansing capabilities of soil.

Today, asphalt paving is an established high-precision standard, and the bitumen it mixes with crushed rock is a hard resin refined from crude oil or tar sands. Somehow that technology will be replaced or transformed as we stop mining fossil fuels. But streets will still need lots of crushed rock in the world to come.

This entry was posted on 25 May 2026 at 7:58 am and is filed under Deep Oakland, Other topics. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.