Transit Officials Go by the Numbers When It Comes to Freeways

Dear Street Smart:

I hear that the new Century Freeway will become the 105. But how did the Riverside Freeway become the 91, the Garden Grove Freeway the 22 and the San Diego Freeway the 405? What’s the deciding factor for how numbers get assigned?

Mario Luna

Anaheim

The numbering systems for interstate and state routes were created to provide uniformity across the United States, said Rose Orem, a spokeswoman for the California Department of Transportation. The rules can be confusing, but they go as follows:

In the interstate system, even-numbered routes usually run east-west and odd-numbered freeways run north-south, Orem said. For example, Interstate 5 heads south from the Canadian border, and ends--or begins, according to your perspective--at the Mexican border south of San Diego.

State routes, such as the even-numbered 14 Freeway (the Antelope Valley Freeway in Lancaster), follow the same pattern.

The numbers of interstate routes, such as Interstate 5 (Santa Ana Freeway), Interstate 405 (San Diego Freeway) and Interstate 605 (San Gabriel River Freeway), contain clues to their function, Orem said. Single- and double-digit routes are freeways connecting the major population centers of the country and generally have 0 or 5 as a last digit, she said.

If an interstate route has a three-digit number and the first digit is even, the route goes around a major city, Orem said. If the first of the three digits is odd, the route is a direct connection into a city. The last two digits of these connector routes are the same as the main artery they serve. For example, Interstate 405 and Interstate 605 connect with Interstate 5.

While the name of a freeway might change as it goes through different cities or states, the number will always remain the same, Orem said. The numbering system for all interstates and state routes are assigned under guidelines set by the American Interstate Highway System established in 1909, she said.

As for how a freeway gets its name, typically it is named for the city where it ends, Orem said. For example, in the past decade, a legislative act renamed the Newport Freeway to the Costa Mesa Freeway because the freeway terminated in the city of Costa Mesa.

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Dear Street Smart:

I have been using the on-ramp for the southbound San Diego Freeway at Euclid Street for 13 years. The on-ramp is entered from Euclid (if you are coming south) or Ellis Avenue (if you are coming north).

This used to be an efficient way to enter the freeway--until metering. The wait time on Ellis between 7:15 and 8 a.m. jumped from about three minutes to 20 minutes, with cars lined up almost a mile to Ward Street. (I do not know the extent of the lineup north on Euclid Street, but from the looks of things, it appears to be another long line).

During this past summer, the metering was discontinued--traffic flowed smoothly onto the San Diego Freeway with nary a difficulty. Last week, the metering returned. I waited 25 minutes on Ellis. Today, the metering was off--easy flow onto the freeway, three minutes or less of waiting time.

While I can understand that metering is essential at parts of the freeway where there is congestion, this area is not congested but rather the traffic flow opens up at this spot without metering. It seems to me that all the cars idling on Ellis Avenue for a much longer time period is worse for pollution and congestion than removing the metering at a spot which flows smoothly.

Clare M. Dellemann

Huntington Beach

According to Caltrans, the meter at the Euclid Street/Ellis Avenue on-ramp to the southbound San Diego Freeway was not discontinued this past summer. However, the meter and controller had been damaged in December, 1992. Caltrans electrical maintenance records indicate that the meter had to be relocated so it would not be damaged in the future, said Caltrans spokeswoman Rose Orem. She said the meter was in operation during the summer.

A field investigation by Caltrans’ traffic operations department revealed that the meter is programmed to operate at the maximum rate, which allows 1,800 vehicles per hour, Orem said.

Traffic on a smooth-flowing freeway, even at peak hours, may appear to be very light. There can be as much as 150 feet between cars that are traveling 55 m.p.h., if drivers are maintaining a safe and comfortable headway, she said.

If platoons of cars are allowed to enter the freeway from unmetered on-ramps, this smooth-flowing freeway would become disrupted by vehicles trying to merge at once, Orem said.

“It could cause congestion and traffic accidents due to weaving between the freeway traffic,” she said.

Controlled ramp meters adjust the timing of their cycles to the actual traffic flow in the vicinity of the on-ramp, Orem said. Caltrans’ traffic operations staff will monitor this location and make adjustments as needed, but the staff cannot turn off this meter because of the volume of traffic on the freeway, she said.

Street Smart appears Mondays in The Times Orange County Edition. Readers are invited to submit comments and questions about traffic, commuting and what makes it difficult to get around in Orange County. Include simple sketches if helpful. Letters may be published in upcoming columns. Please write to Caroline Lemke, c/o Street Smart, The Times Orange County, P.O. Box 2008, Costa Mesa, Calif. 92626. Include your full name, address and day and evening phone numbers. Letters may be edited, and no anonymous letters will be accepted.