Transportation Impact Studies, B-Permits, & CTTC

Transportation Impact Studies 

The LADOT Development Review Division requires the preparation of either a focused technical analysis or a comprehensive transportation impact study (TIS) of proposed land use and transportation projects that may impact the efficiency and safety of the City’s transportation network.

Generally, LADOT uses the following criteria to determine which projects shall be evaluated:

  • LADOT requires a technical analysis to determine potential transportation impacts and mitigation needs for projects that are estimated to generate an increase of 25 to 42 net vehicle trips during the morning or afternoon peak commute hour.
  • LADOT requires a transportation impact study (TIS) prepared by a licensed traffic engineer that conforms to our TIS guidelines for projects that are estimated to generate 43 or more net peak hour vehicle trips.  Traffic volume data may be available to assist the preparation of the TIS analysis.  If the TIS identifies significant impacts resulting from the proposed project, LADOT will work with the project applicant to identify mitigations.  Those mitigations will be formally transmitted to the Department of City Planning and will become official conditions on the project’s approval.

See the City of Los Angeles Transportation Impact Study Guidelines for detailed information on TIS evaluation criteria, requirements, and mitigation measures. Development review fees for transportation impact studies may apply.

Mitigating Transportation Impacts

While mitigation for projects estimated to generate transportation impacts depend on specific characteristics, measures may include one or more of the following:

  • Trip reduction measures
  • Transit, bicycle, and/or pedestrian improvements
  • Shared mobility program improvements
  • Lane restriping
  • New traffic signal installation
  • Existing traffic signal modification (e.g. left turn phasing)
  • Traffic signal system upgrade
  • Parking management strategies
  • Monetary contributions to exiting trust funds or transit/shared mobility capital/operations and maintenance


Any extensive physical change to the city’s streets requires a B-Permit issued by the Department of Public Works/Bureau of Engineering (LAMC Sec. 62.106.b).  Typical B-Permit includes street and alley widening, and street improvements for private development.  As part of those changes, LADOT reviews and approves the final striping and signal plans.  LADOT staff can be reached at and can assist project applicants.  Design Resources for Traffic and Civil Engineers in the design of traffic improvements are listed below:

Citywide Temporary Traffic Control (CTTC) 

The CTTC Division of the City of Los Angeles Department of Transportation reviews and oversees implementation of short-term (less than 72 hours) Temporary Traffic Control Plans. Our function is to ensure Contractor compliance with Federal and State principles and standards when implementing Temporary Traffic Controls (TTC) on City Right-of-Way. This is intended to provide for the safe and efficient movement of road users through and around TTC zones while reasonably protecting users, workers, and equipment in accordance with the California Manual of Uniform Traffic Control Devices, CAMUTCD, Part 6 (2016).This page provides guidance & information needed to submit Worksite Temporary Traffic Control Plans to the CTTC Division. These items will assist our team in understanding the nature of your work, and help us in providing a quick turn-around time for our review. 

1) Cover letter on company letterhead, listing contact information, job location, approximate start and duration of work (for each Phase if applicable), City Agency Permit Log #, Company project #, and a brief description of project work. Click Here for Sample of Cover Letter

2) Construction Plan showing dimensions to property lines or other pertinent reference points. Click Here for Sample of Construction Plan

3) Copy of appropriate City Agency Permit Application, or Permit if already issued. Click Here for Sample of Permit Application

4) Worksite Traffic Control Plan (Conceptual) showing the following: Click Here for Sample of Plan
- Existing conditions of the worksite and roadway showing striping, lane widths, intersection & driveway locations, and signalization or Right-of-Way assignment controls. (field verification of existing conditions is required - include photos).
- Identify any major businesses and/or entities around the proposed work areas, such as schools, hospitals, stadiums,commercial centers, etc.
- Identify appropriate Pages from current WATCH Manual or Typical Applications from current CAMUTCD being implemented. 

To initiate review of your Worksite Traffic Control Plan, (WTCP) please   click Here CTTC  and provide ALL required project information listed above.