Overall, new development within the UVSP is regulated by a mechanism known as a “Trip Budget,” which is based on the amount of traffic new development could generate. (See FAQ No. 1.) However, it’s unclear at this time how State legislation identified in FAQ No. 21 would affect the UVSP Trip Budget for a housing or mixed-use project. The City is still evaluating the reach and impact of new State legislation on City development regulations.
Typically, the Trip Budget relies on traffic information published by the Institute of Traffic Engineers (ITE) to predict the amount of traffic a project will create. ITE trip rates are currently calculated based on ITE’s 10th edition of Trip Generation. The City specifically looks at “peak-hour” trips, which is traffic generated during the morning and evening “rush-hour” periods in evaluating traffic for purposes of the UVSP Trip Budget. These rush-hour periods are commonly referred to as “AM Peak” and “PM Peak” hour, respectively. Currently the UVSP has 335 trips in the AM peak hour and 1,680 trips in the PM peak hour available to accommodate traffic from new development. These trips are available on a first-come/first-serve basis. It should be noted that the remaining traffic figures above reflect the trips remaining after deducting trips from the Five Lagunas project approved in 2016. With each new development project, the City reduces the peak hour trips available within the UVSP based on a traffic study.
Also, the UVSP only recognizes “net new trips,” meaning property owners are given a credit for vehicle trips associated with existing buildings that are demolished and replaced with new buildings and/or uses. For example, if a 1,000 square-foot retail building was demolished, roughly seven (7) multi-family housing units could be rebuilt in its place with no net increase in vehicle trips. In this example, a 1,000 square foot retail building generates 3.81 vehicle trips, where seven (7) multi-family units generate 3.5 vehicle trips, or 0.5 trips per unit. For office uses, an 8,000 square foot office building could be built in place of a 1,000 square foot retail building since an office building only generates 0.47 trips for every 1,000 square feet. The vehicle trips described above reflect trip generation rates during the PM Peak hour since the PM Peak hour generates the highest traffic levels, although traffic for the AM and PM Peak hours will both be analyzed for the new project.
The table below depicts the relationship between uses and vehicle trips for each of the uses described above.
Per 1,000 Square Feet
Per 1,000 Square Feet
*PM Peak Hour
ITE occasionally updates its trip generation rates, and the City always uses the most current edition available.
March 2021 Update: The completed traffic study for the project indicates an overall decrease in project traffic due to the elimination of retail square footage. Compared with anticipated traffic from Five Lagunas, Village at Laguna Hills will have nearly 10,000 fewer cars per weekday and over 15,000 fewer cars on the weekend since office and residential uses generate fewer vehicle trips than retail development as described above. Peak hour traffic during the evening commute period will also decline by over 900 vehicles. However, traffic during the peak morning commute period will increase by 119 vehicles compared to traffic anticipated from Five Lagunas.