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1352 W. Olive Avenue
P.O. Box 12616
Fresno, CA 93778-2616
- (559) 488-4082
- (559) 444-2409
- 711 - TTY
Traffic Engineering FAQs
The Office of Traffic Engineering works with Project Development, Construction, Planning, and other Caltrans departments to provide a safe and efficient highway system within District 6. Its primary functions include providing safety analysis, traffic operational analysis, and planning and design reviews to Project Development. This office also supports Construction by reviewing safety-related features in the field and by providing recommendations regarding construction safety devices.
Traffic Engineering supports Planning’s Intergovernmental Review functions by reviewing proposed developments and providing recommendations related to safety and operations. This office also administers the traffic census count program for Caltrans headquarters.
An operational analysis should be performed for all capacity-increasing projects or developments. A level-of-service (LOS) is typically calculated for opening-day traffic volumes and for 20 years beyond the completion of construction. The results of the operational analysis are used to develop recommendations for geometric configurations and traffic controls. The LOS of highway segments and intersections ranges from LOS A to LOS F. Caltrans District 6 strives to maintain an LOS C or better on all state facilities within the district.
Traffic Engineering performs a safety analysis for all Caltrans pavement rehabilitation projects. A safety analysis typically includes information regarding accident data, traffic safety devices, and roadside obstructions. Construction safety reviews are performed for all construction projects to ensure that any safety-related issues are addressed. Through the Intergovernmental Review process, Traffic Engineering reviews private developments to determine if there are any safety-related issues associated with the proposed development. The most common safety issues related to private developments are those regarding sight distances and clear recovery zones.
Traffic counts are taken on all state highways on a three-year cycle. Counts are also taken for ramps and local cross-streets. This information is available on the following website: http://www.dot.ca.gov/hq/traffops/saferesr/trafdata/
Some counts are taken by placing rubber hoses across the highway. There are also permanent count stations with inductive loops. Some count stations are capable of classifying trucks by the number of axles. Turning movement counts are more complex and currently require that one or more individuals collect data through onsite observations.
Intergovernmental Review is a legally mandated program that requires Caltrans, pursuant to the California Environmental Quality Act statutes and guidelines, to review federal, state, and local planning and proposed development activity that has the potential to affect state transportation facilities or resources under Caltrans’ jurisdiction. Caltrans’ role is to recommend conditions of project approval that mitigate those impacts or reduce them to a level of insignificance. This typically involves the review of development proposals in which Caltrans is either a responsible (permitting) or commenting agency, but has no discretionary approval power over the project other than permit authority.
Lead agencies, typically cities or counties, are required to route those proposed projects or developments that could generate traffic that potentially could affect state highways. The Caltrans District 6 Planning Division will initially receive the documents (site plans, environmental documents, traffic studies, etc.) routed by the lead agencies. Planning’s Intergovernmental Review Branch will then seek input from Design and functional units to formulate a coordinated response from Caltrans. In most instances, Planning will rely heavily upon the comments and recommendations it receives from the District 6 Office of Traffic Engineering.
The District 6 Office of Traffic Engineering will review proposed projects and developments to determine if there will be any safety or operational impacts to state facilities. This will typically be accomplished by estimating the amount of traffic that would be generated by a project or development, and then determining when and how much of the generated traffic would affect a state facility. The location and number of driveways are usually also a critical issue that is reviewed and commented on.
After the information has been reviewed, this office may determine that there will be a negligible impact from the development, or it may be determined that the impacts are so potentially significant that a more in-depth study (Traffic Impact Study) is required. Impacts from the developments may sometimes warrant the need for traffic signals or left-turn/right-turn lanes. Impacts may be so significant that a whole new interchange may be needed to mitigate a project’s impacts.