Asphalt or concrete lanes? Both are used on 405 Freeway and elsewhere

Q. I was wondering why there are two different surface materials used in the construction of the new lanes on the 405 Freeway in Orange County. It makes for a rough ride in the areas where the two surface types adjoin. I’m sure it’s a common practice, but I’ve just noticed it on the 405 in the Fountain Valley/Westminster area with the recent completion of the freeway widening.

– John Doyle, Newport Beach

A. The ol’ wise one enjoys guiding the Honkmobile on a ribbon of pristine black asphalt, with white lane lines glistening.

He does not particularly like driving on the rougher concrete freeway lanes, which can be as ugly as an old Honk tie.

To provide sufficient traction, the concrete has groves while asphalt doesn’t need them. Plus, there are joints between the concrete slabs.

But Honk does understand concrete’s importance in the asphalt jungle.

It costs more to put in concrete lanes, although in the end they are less expensive.

Concrete can endure for 40 years, one Caltrans official told Honk a few years ago, with asphalt lasting perhaps 10 years and at times a couple of decades.

Typically, the price tag to rehabilitate a single, aging concrete lane for one mile is $250,000, Caltrans says. For a lane mile of asphalt, it’s $450,000.

When mulling over which of the two surfaces to use for a freeway lane, pavement engineers consider the soil, the cost, and how structurally sound the lane would be. And remember, each time a freeway lane is worked on, it is shut down – often irritating the motoring public – another consideration of pavement engineers.

On the 405 in Orange County, there was a patchwork of the two materials.

“This is a result of different projects over time, with different objectives, budgets, anticipated traffic loads and other site-specific considerations, resulting in projects choosing different pavement strategies,” said Sheilah Fortenberry, a Caltrans spokeswoman.

The Orange County Transportation Authority recently oversaw the $2.16 billion widening of the 405 in that stretch, between the 605 Freeway and the 73, and largely used concrete for the new lanes and asphalt for transition areas and shoulders.

As Honk recently explained after his electronic mailbox was visited by a flurry of complaints of the rough ride in that area after the two billion-plus was spent, Caltrans intends to smooth out the older lanes beginning next year.

HONKIN’ FACT: Last year across the country 1,105 bicyclists were killed, and another 46,195 reported injured, according to the National Highway Traffic Safety Administration.

To ask Honk questions, reach him at honk@ocregister.com. He only answers those that are published. To see Honk online: ocregister.com/tag/honk. Twitter: @OCRegisterHonk

Source: Orange County Register