Traffic is one thing that residents of Almaden Valley share in common, and we are very aware of changes in traffic congestion.  Almaden Expressway is the principal roadway in Almaden Valley.  There are ten major intersections along the expressway, from Blossom Hill Road to Harry Road.  The busiest of these intersections are Blossom Hill Road, Coleman Road, and Camden Avenue.  Let's look at the measurements of traffic and see what they indicate.

According to data taken in October, 2001, the twenty-four hour traffic totals taken in both directions along Almaden Expressway are:

The County measures this data for specific purposes, and the 2004 data does not match the 2001 data, but some information can be observed about the change in traffic density. For example, comparing the 2004 data from Via Monte to Redmond and Redmond to Trinidad with 2001 data from McAbee to Redmond and Redmond to Camden, it can be seen that the traffic density is less in 2004 than in 2001.  This might be due to reduction of employment after the technical bubble burst.

Traffic engineers use automatic data gathering from the transmissions of test cars and a computer program to come up with a descriptive status of traffic conditions.  The output of this program is called the Level of Service (LOS).  These levels are described with designations "A" through "F", with "A" being the best and "F" being the worst.  The measurements are usually taken during the busiest two hours of peak use, for instance, from 4:00 PM to 6:00 PM on week days.

Now let's look at a more detailed description of LOS.  Table 3, above, gave the time range for each LOS.  The LOS definitions in Table 4, below, are given in the 1985 Highway Capacity Manual, Special Report No. 209, Transportation Research Board, Washington D.C.

The National Standard for minimum satisfactory traffic congestion is Level of Service "D".  LOS "D" is recognized by the City of San Jose as the minimum acceptable level of service.  In the 1985 Highway Capacity Manual (Transportation Research Board, Washington, D.C.), the next level down, LOS "E", is called "extremely unstable, driver comfort poor, average traveling speed 28 mph for a 50-mph-designed expressway, and minor incidents causing serious breakdown with extensive queuing."  In 1988 there were two San Jose intersections at LOS "F".  In February, 2004, there were fifteen at LOS "F".  The worst intersection was Montague/Trimble where the average rush hour delay was 270 seconds.

The LOS levels above were measured as the time that a vehicle was stopped at a red light.  In 2004, the method of calculating the LOS values was changed to include the time of deceleration to a stop light plus the time to accelerate after the light turns green in addition to the wait time at a red light.  This has resulted in improved LOS levels for the same amount of traffic.  The new LOS calculations are based on the 2000 Highway Capacity Manual calculation method replacing the previous 1995 Highway Capacity Manual calculation method. AVCA has complained to the County Roads Department that the new method distorts historical comparisons of the LOS values.

Under the new method of calculating the LOS, the values for Almaden Expressway intersections are:

LOS values:	2004	2005	2006
Camden Ave.	D	*	D
Coleman Rd.	D	*	D
Blossom Hill Rd.	E	*	E

The LOS levels for 2004 are improved over the 2002 levels, again perhaps reflecting the reduction of employment in the San Jose area and the new method of calculation.

Traditionally, the lowest acceptable Level of Service (LOS) for traffic intersections was "D".  Because the principal Almaden Expressway intersections were at LOS "F" in 1991, a new, acceptable, LOS "E" was agreed to by the county in that year.  It is seen that the Almaden Expressway was below that level of service in October 2001, and hit bottom at the Blossom Hill Road intersection.  Under the new method of LOS calculation and with the reduction of employment, Blossom Hill Road has met requirements, although when it is driven at rush hour, for the public, an LOS "F" gridlock impression remains.  In the Transportation 2000 Report, it was suggested that a grade separation be constructed at Blossom Hill Road, but the cost has discouraged the County from considering it.

Almaden Expressway is under the jurisdiction of the Santa Clara County Traffic Authority.  The other roadways in Almaden Valley are under the jurisdiction of the City of San Jose Department of Streets and Traffic.  Both offices were helpful in supplying information for this article.

Development in Almaden Valley is totally under the control of the City of San Jose.  However, the county can request that the city require developers to make improvements to Almaden Expressway to mitigate any new traffic caused by their developments.  In addition to Almaden Expressway, the county controls seven other expressways, two of which are Capitol and San Tomas Expressways.

It was mentioned above that LOS "D" is recognized by the City of San Jose as the minimum acceptable level of service.  According to 1999 data, during peak hours (generally between 7 AM and 8 AM, and between 5 PM and 6 PM), 64 percent of San Jose's freeways and 18 percent of expressways were at LOS level "F", and 7 percent of local streets were at LOS level "E" or "F".  It would be interesting to see more recent data on the LOS levels for these various types of streets.

Appreciation is expressed here for cooperation of the following individuals in obtaining the information necessary for this article:
      Thien Pham, Masoud Akbarzadeh and Suhil Kandah, County of Santa Clara Roads and Airport Departments Traffic Engineering and Operations.
      Tom Ho, City of San Jose Traffic Engineer for District 10.