MOVING YOLO COUNTY'S ROADS INTO THE 21ST CENTURY
By Dave Rosenberg
Yolo County Supervisor, District Four
Here's a quiz. How many miles of roadway does Yolo County have (not
including state and interstate highways like 80, 5, 505 and 113)?
(a) 2,352
(b) 803
(c) 427
(d) 325
(e) 295
The answer to this roadway quiz can be found at the end of this article.
Suffice it to say that Yolo County has plenty of roadways to maintain.
Recently, Yolo County Public Works (with the approval of the Board of Supervisors)
instituted a new, cutting-edge program to manage and maintain our roadways.
Yolo County has instituted a Pavement Management System (PMS) which was
originally developed by the Metropolitan Transportation Commission in the
San Francisco Bay Area. This system is used by all counties encompassing
the Bay, and now, by Yolo County. The benefit of having a PMS used by our
neighboring counties is that we will all now be "speaking the same language" when
it comes to roadways. This will help us more effectively communicate with each
other as we work on joint meetings, seminars and projects.
What is Yolo County's PMS?
It's a system that helps us forecast roadway maintenance needs within
the county. The system is an effective tool to help our technicians track
maintenance needs on an on-going basis and allows the county to maintain
our roadways in the best condition our budget will allow.
How does the system work?
The system divides each road into manageable segments. After the roads
are segmentalized, surveyors are sent out to measure the road distresses,
and the information they gather is keyed into a computer. From there, the PMS
program assigns a score from 0 to 100 to each road segment. This score is the
Pavement Condition Index (PCI). A road segment with a PCI of 100 is in brand
new condition. This segment does not have any distresses. Lower PCI's indicate
more wear and tear on the roadway. A road with a PCI of 0 is a very unhappy road.
In order to keep the data well organized, the roadways are segmentalized
into manageable units. The segments are large and significant enough to warrant
a construction project if need be, yet are not so long such that the county
could not afford to treat an entire segment as a project. Each segment only
contains one road surface type, and only one functional classification.
The segment names are simple. They contain a code for the road number
plus a segment number that follows. For example, County Road 102 is segmentalized
thusly: 102-10, 102-20, 102-30, 102-40 ... This clearly illustrates that the
road in question is CR 102, and the segments (10, 20, 30 ...) identify specific
lengths of the road in sequential order.
The PMS rates road segments based on their PCI score. In order to
calculate the PCI, inspectors survey the road segment by actually walking the
inspection unit, measuring the different distresses, and recording the type,
severity and amount of each distress present in the segment. The distresses that
are calculated are: Alligator Cracking, Block Cracking, Distortions, Longitudinal
and Transverse Cracking, Patching and Utility Cut Patching, Rutting and Depressions,
and finally, Weather and Raveling. These distresses are measured by linear foot
or by area, and are subsequently assigned a rating of High, Medium or Low. After
these distresses are entered into the PMS, a computer calculates the PCI. The
PCI ratings are as follows:
100-86 Excellent
85-71 Very Good
70-56 Good
55-41 Fair
40-26 Poor
25-11 Very Poor
10-0 Failed
Roads are categorized as Category I, II or III. Category I ranges from
a PCI of 70 or above. Roads in this category only need minimal preventative maintenance
to maintain their PCI's in the Very Good range. Categories II and III comprise
the "Good" PCI's. This category is divided between load-related and
non-load related distresses. Roads in Category II and III may require some preventative
maintenance (such as crack sealing) or may require a light overlay to bring their
PCI's into the Very Good range. As road quality declines into the Poor and Very
Poor categories, the roads require increasingly more intensive repairs which
may include thick (3 inch) overlaps, or even reconstruction. Ideally, all county
roads would be maintained at a PCI of 70 or above, but this goal exceeds the
county's current funding.
Ready for the answer to the roadway quiz?
There are 803.84 miles of roadway surface in Yolo County. Of the 803 miles
of roadway in Yolo County, the following are the types of material used:
(1) 276.2 miles are dedicated to asphalt-concrete (and another 1.55
miles is concrete). This sort of material is used on county roads subject to
heavy vehicles and large traffic volumes.
(2) 397 miles of county roadways are surface-treated, that is
chipseal. This material is used on roads subject to moderate traffic volumes.
It costs less to use chipseal than to use asphalt-concrete.
(3) 101.99 miles are in gravel and another 27.1 miles are graded (the
latter designates roadways made up of graded roads using material found on site).
It?s the cheapest to maintain, but puts wear and tear on vehicles. These roadways
are used where traffic volumes are quite low.
And you can help too!
If you drive along county roads and find a pothole or other problem, please
report it to County Public Works at 666-8775.