Prioritizing and Scheduling Roadways for Pavement Rehabilitation
The City of San Ramon has approximately 214 miles of streets to maintain. To ensure the safety of our roadways, the City’s Pavement Management Program (PMP) reviews the condition of every City-owned street and maximizes the number of streets that can be repaired based on available funding. Priority is given to the busier roadways (arterials and collectors), neighborhood areas with poor pavement conditions, streets that need full reconstruction, and streets eligible for slurry seal (a preventative maintenance treatment) that extends the life of the pavement.
The PMP includes the preparation of the Five-Year Pavement Repair Plan, updated annually as part of the City’s Budget Process. The basis of the Plan is the pavement condition survey performed biennially in which a Pavement Condition Index (PCI) is assigned to each street section (0-100). The Plan identifies the streets to be repaired, reconstructed, or slurry sealed within a five-year period. The Annual Paving Project is then developed and constructed each summer. This year, Bollinger Canyon Road and Crow Canyon Road near the I-680 interchanges and various residential streets were repaved; Montevideo Drive and Camino Ramon were slurry sealed.
The following information will provide some insight on the strategies that the City uses to prioritize and schedule streets for pavement rehabilitation.
First, to describe the pavement repair strategy, explanation of the following terms and definitions may be helpful:
Pavement Management Program - The City’s Pavement Management Program consists of the Annual Pavement Management Project and the Pavement Repair Stop Gap Project.
Annual Pavement Management Project - The annual pavement management project, which provides for the long-term scheduled maintenance of the City’s street network, is normally bid once a year with the construction contract ending upon completion of the scheduled work. The construction duration for an annual pavement management project typically takes approximately four months to complete.
Pavement Repair Stop Gap Project - The pavement repair stop gap project provides for immediate repairs of localized failed pavement that are a safety concern. The pavement repair stop gap is currently bid on a biennial basis and the construction duration is two years. Locations of failed pavement that are reported are compiled into a list and issued to the contractor in the form of a “Work Order” for repair throughout the contract period.
Pavement Condition Index (PCI) - PCI is a numerical index between 0 and 100 that is used to indicate the general condition of a pavement. It is widely used in transportation civil engineering. It is a statistical measure and requires field survey of the pavement.
Low PCI Roadways – If arterials, collectors, and residential roadways have a PCI of less than 50, 45, and 35, respectively, they are labeled as “Low PCI” roadways for pavement repair purposes and are eligible to receive a complete pavement reconstruction, a criteria that was established by the City to ensure that pavement sections that reach these PCI ratings are prioritized and addressed.
High PCI Roadways – If arterial or collector roadways have a PCI of 70 or more and residential roadway have a PCI of 65 or more, they are labeled as “High PCI” roadways for pavement repair purposes and are eligible to receive preventive maintenance treatment, i.e. slurry seal.
Neighborhood Areas – A neighborhood area is an area that consists of a subdivision development or a combination of subdivision developments delineated by either a collector or an arterial roadway. For pavement repair purposes, the neighborhood area is formed to provide pavement rehabilitation to a group of streets in a particular area.
Pavement Treatment Type – Different roadways or even different sections of a roadway may receive different pavement treatment depending on its pavement condition and its current PCI. In general, there are two types of pavement treatment: Preventive Maintenance Treatment and Pavement Rehabilitation.
- Preventive Maintenance Treatment – Preventive maintenance treatment is designed for sealing cracks and preventing the roadway pavement from further cracking thereby increasing the roadway pavement longevity. The treatment consists of primarily crack sealing followed by some type of seal coat such as slurry sealing. Arterial and collector roadways with a PCI of between 70 and 90, and residential roadways with a PCI of between 65 and 90 are eligible to receive preventive maintenance treatment approximately every six years. The cost of preventive maintenance treatment is relatively less expensive and is currently anywhere from $4.00 to $5.50 per square yard. Preventive maintenance treatment improves the PCI of a roadway by 5 to 8 points.
- Pavement Rehabilitation – Pavement rehabilitation is applied to pavement that is relatively old and has developed larger cracks, distortions, rotting and raveling. Pavement rehabilitation consists of a variety of different treatments including inlay, overlay, pavement reconstruction, etc., but should not include preventive maintenance treatment. Arterial and collector roadways with a PCI of less than 70, and residential roadways with a PCI of less than 65 are eligible to receive pavement rehabilitation approximately every twenty years. The cost of pavement rehabilitation is relatively more expensive and it is currently anywhere from $28.00 to $80.00 per square yard depending on the roadway classification and its PCI. If the roadway is an arterial with a low PCI, the cost of pavement rehabilitation is close to $80.00 per square yard. On the other hand, if the roadway is a residential with a PCI close to 65, the cost of pavement rehabilitation is close to $28.00. Pavement rehabilitation always improves the PCI of the roadway to 100.
FIVE-YEAR PAVEMENT REPAIR PLAN
As part of the City’s Annual Budget review and approval process, a Five-Year Pavement Repair Plan is prepared and updated annually. The Pavement Repair Plan primarily contains five neighborhood areas from the prioritized neighborhood area list for the following five years, sections of prioritized arterials and collectors when there is funding available, low PCI roadways, and roadways eligible receiving preventive maintenance when there is funding available.
- Prioritizing and Scheduling Neighborhood Areas - The City obtains an independent pavement engineering consultant on a biennial basis to evaluate the condition of each and every management section in San Ramon. After completing the condition survey, the PCI of the existing management sections are updated and the newly constructed roadways are assigned new PCI values and added to the database. The City then calculates the average PCI of the residential management sections located in each neighborhood area and prioritizes them from the lowest to the highest with the lowest as top priority area. The top five neighborhood areas from the priority list are then programmed into the Five-Year Pavement Repair Plan.
Individual roadways within the neighborhood area receive different treatment depending on the PCI values. For example, if a roadway within the neighborhood area has a PCI value over 65, the roadway will receive a preventive maintenance treatment; if another roadway within the same neighborhood area has a PCI value between 25 and 65, the roadway will receive either an overlay or an inlay; finally, if a roadway within the same neighborhood area has a PCI value of less than 25, the roadway will receive a complete pavement reconstruction.
- Scheduling Arterials and Collectors – The City calculates the average PCI of the management sections within each arterial and collector roadway and prioritizes them from the lowest to the highest with the lowest as top priority arterial or collector. Arterials or collectors are eligible to receive grant funding from Federal or State. The City constantly seeks grants to finance the pavement rehabilitation of arterials and collectors since the Gas Tax Fund is not always enough to finance both arterial or collector and a residential neighborhood area in the same year. However, in the absence of any grant funds and due to further deterioration of the arterial or collector roadway pavement, the City may find it necessary to prioritize an arterial or collector in a particular year due to the higher vehicular use compared to residential streets.
- Scheduling Low PCI Roadways - In addition to the scheduling of residential roadways in the prioritized neighborhood areas and prioritized arterial and collector roadways for pavement rehabilitation, the Five-Year Pavement Repair Plan provides for the programming of arterials, collectors, and residential roadways with a low PCI. These low PCI roadways, as defined, are selected from the areas that are scheduled for beyond five years based on neighborhood area priority and are programmed into one of the five years based on the cost and close proximity to a particular neighborhood area selected for that year, with the lowest PCI roadways scheduled within the first two years taking into account funding availability and prioritization.
- Scheduling High PCI Roadways – When funding is available, the City selects and schedules a residential neighborhood area or an arterial or a collector roadway with high PCI values into the Five-Year Pavement Repair Plan for preventive maintenance treatments. These roadways are either approximately 6 to 10 years old or are existing roadways that received pavement rehabilitation approximately 6 to 10 years ago. Again, the purpose of preventive maintenance application to these roadways is to prolong their life span, which is considered a prudent way of spending fewer tax dollars to maintain roadways in better condition.
In addition to the programming of the roadways into the Five-Year Pavement Repair Plan, any roadway section that has a severely localized damaged area and is waiting to be prioritized and programmed into the Five-Year Pavement Repair Plan can be repaired as part of the pavement repair stop gap project.