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The Traffic Control Process, Step by Step

Most delays on traffic control jobs are not caused by the setup itself. They come from missing information at the start, a plan that does not match the street, or a permit that was not ready on the day crews show up. This page lays out the typical sequence for a traffic control job in California, from first site details to final cleanup, so you know what to have ready at each stage.

Every agency runs its own process, so treat this as a map, not a rulebook. Always follow the specific requirements of the city, county or Caltrans district that owns the road.

The process at a glance

  1. Gather site information
  2. Choose the approach and prepare the traffic control plan
  3. Submit to the agency (with the permit application)
  4. Respond to comments and receive approval and the permit
  5. Notify and schedule
  6. Set up the work zone
  7. Inspect and maintain it during work
  8. Remove devices and restore the site

Step 1: Gather site information

A traffic control plan is only as good as the information behind it. The CA MUTCD (Section 6B.01) lists the variables that shape every work zone: location of work, road type, geometry, intersections, traffic volumes, the mix of drivers, cyclists and pedestrians, the mix of vehicles, and speeds. In practice, the plan preparer needs:

  • The exact location and limits of the work (cross streets, addresses, which side of the street)
  • What work is being done and what equipment will be in the road
  • Which lanes, shoulders, bike lanes, parking or sidewalks will be affected
  • Days and hours of work, and whether any work is at night
  • How long the work will last at one spot (hours, days, or weeks)
  • Nearby driveways, bus stops, schools, businesses and emergency facilities
  • The permit type and agency, if already known

Photos or a street-level view of the site help catch things like existing striping, medians and bike lanes. San Diego’s bulletin, for example, puts responsibility on the applicant for a complete representation of the actual road conditions on the plan, including existing striping, signing, sidewalks and bike lanes.

Step 2: Choose the approach and prepare the plan

Next comes the decision about how to move traffic: signs only, a shoulder closure, a lane closure, one-lane two-way operation with flaggers, a full closure with a detour, or a combination in stages. The lane closure vs road closure page covers the trade-offs.

For simple, common layouts, some agencies accept a standard drawing. On State highways, Caltrans allows its Standard Plans for Traffic Control Systems when they fit the site conditions; if they do not, the applicant must have a California registered engineer develop and stamp site-specific plans. In the City of Los Angeles, LADOT’s flowchart for short-term work (72 hours or less) sends some sites to a typical application from the WATCH manual, the CA MUTCD or a City standard plan, and others to a professionally prepared or engineer-designed plan.

A site-specific plan typically shows the street layout, sign types and locations, taper and buffer lengths, device spacing, flagger stations if any, pedestrian and bicycle routing, work hours, and notes required by the agency. See traffic control plans and, for bigger projects, TCP vs TMP.

Step 3: Submit to the agency

The plan is usually submitted with, or as part of, a permit application:

  • Caltrans: the Standard Encroachment Permit Application (form TR-0100) goes to the district office, with plans and supporting documents. District 12 (Orange County), for example, strongly encourages electronic submission by email.
  • City of San Diego: a Traffic Control Plan/Permit form (DS-269) and the plan are submitted through the City’s Accela system at least five working days before work in the right-of-way.
  • City of Los Angeles: plans that need LADOT review go through its Permit Plan Review Section, which requires a first submittal meeting for temporary traffic control plans.
  • Counties: LA County and OC Public Works each use their own permit systems and will state whether a traffic control plan is required.

Lead times vary widely by agency, plan complexity and time of year. Submitting early is the single easiest way to protect a start date.

Step 4: Comments, approval and the permit

Reviewers often return comments: move a sign, lengthen a taper, change work hours, add a pedestrian detour. Revised plans are resubmitted until approved. On Caltrans permits, the approved traffic control plans are made part of the encroachment permit, and lane closures are limited to hours approved by the traffic reviewer.

If field conditions later require a different setup, don’t improvise. The CA MUTCD states that a modified or alternate TTC plan shall have the approval of the responsible highway agency before it is put in place. On State highway permits, the Caltrans Encroachment Permits Manual directs requests to revise or use different traffic control plans to the District Traffic Engineer for approval, and notes that Caltrans Standard Plans cannot be revised for individual projects.

Step 5: Notify and schedule

Approved permits often carry conditions: notifying the agency inspector before starting, posting advance notice for residents or businesses, coordinating with transit, or entering closures in a scheduling system. On State highways, planned closures run through Caltrans’ Lane Closure System, a statewide web application used to request, review, approve and monitor lane closures, which also feeds public closure information. Confirm who is responsible for each notice.

Step 6: Set up the work zone

Crews generally place devices in the order traffic will encounter them, starting with advance warning signs and working toward the work area, so drivers are warned before they reach anything new. The setup should match the approved plan: sign types and positions, taper lengths, device spacing, buffer space and pedestrian routing.

Cal/OSHA requires workers on foot exposed to traffic to wear high-visibility garments, retroreflective at night, and requires flaggers to be trained before they are assigned. See flagging in California.

Step 7: Inspect and maintain

Once traffic is flowing, the zone needs regular checks. Cones get knocked over, signs get turned by wind, lights fail, and conditions change as work progresses. Agency inspectors may visit to verify the setup against the approved plan. Keep a copy of the approved plan and permit on site.

Step 8: Remove devices and restore

Removal generally runs in the reverse order of setup, taking down the devices closest to the work first and the advance warning signs last. Signs that no longer apply must not be left up: for example, the CA MUTCD requires reduced work zone speed limit signs to be covered or removed when work is not in progress unless traffic is still affected, and ROAD CLOSED signs may not be used where traffic is actually still flowing through with fewer lanes. Restore any striping or markings that were covered or removed as the permit requires.

Frequently asked questions

How far ahead should I start the traffic control process?

As early as you know the location and scope. Some agencies set minimums (San Diego requires at least five working days for its traffic control permit), but review times for complex or engineered plans can be longer. Ask the agency for current timelines.

Can I use a standard plan instead of a custom one?

Sometimes. Caltrans allows its Standard Plans when they fit the site; LA City allows typical applications for certain short-term work on certain streets. If the standard drawing does not match the real street, a site-specific plan is needed.

What happens if the approved setup doesn’t work in the field?

Stop and contact the agency. Changes to an approved plan need agency approval before they are implemented.

Who removes the traffic control at the end?

Usually the same crew or company that set it up, following the permit’s conditions and working hours.

Want a hand with the process?

Safe Pass Traffic prepares traffic control plans for projects anywhere in California (PE stamps available), along with striping plans and Caltrans encroachment permit support. Field crews, flaggers and equipment cover Orange, Los Angeles, San Diego, Riverside and San Bernardino counties. We’re open 24 hours. Call or text (714) 362-1348 or request a quote.

Related guides

How Safe Pass Traffic can help

Sources

This guide is general information based on the sources above, not engineering or legal advice for a specific site. Requirements vary by agency and project.