City of Henderson Traffic Impact Study (TIS) Guidelines Summary
A Traffic Impact Study (TIS) is generally required for development projects generating 100 or more peak hour trips. However, the City of Henderson (COH) reserves the right to require a study regardless of trip volume, based on development type and location. TIS updates are mandatory as phases of a project are built.
Trip Generation
Trip generation must be calculated using the most recent edition of the Institute of Transportation Engineers (ITE) Trip Generation Manual and Section 3.4 of the Trip Generation Handbook, which outlines the recommended procedure for estimating trips. For pass-by trip reductions, data from the ITE Manual must be used. Reductions are not permitted for driveway volumes or diverted link trips. Both pass-by and primary trip figures, including their distribution and assignment, must be approved prior to formal submission. Internal capture combined with pass-by reduction is only allowed if approved by COH.
Mixed-use projects of regional significance must have internal capture rates reviewed and approved by the City Traffic Engineer or designee before submitting the study.
RTC Transit Routes
Bus turnouts are required on the far side of all intersections classified as Major Collector or higher. A combination turnout and right-turn lane may be mandated depending on the site layout. Additional locations for bus turnouts will be reviewed case-by-case.
Level-of-Service (LOS) Analysis
LOS calculations must be based on the current edition of the Highway Capacity Manual. If an unsignalized intersection operates below LOS C (i.e., D or worse), three potential mitigation measures must be proposed, such as signalization, turn lanes, medians, or lane additions. Similarly, signalized intersections operating below LOS D (i.e., E or worse) require the analysis of three mitigation options. Each option should include a discussion of pros and cons. Regardless of whether mitigation improves LOS, the analysis must be included in the TIS to allow the City to determine necessary measures and understand regional traffic impacts.
Signal Warrant and Progression Analysis
Signal warrant analyses must follow the latest Manual on Uniform Traffic Control Devices (MUTCD). The peak hour warrant generally cannot justify a signal for typical residential or commercial uses. The City may allow projected volumes for 8-hour signal warrant analyses. If a new signal is needed on a corridor managed by FAST (Freeway and Arterial System of Transportation), both the location and progression analysis must be submitted to FAST for review. The progression analysis must assume a minimum 40% green band per cycle unless otherwise approved.
Queuing Analysis
Residential gated communities must include queuing analyses for driveways, using a 30-second service time and a single-lane queue. Separate visitor lanes and turnarounds per RTC Standard Drawing No. 222.1 are required. The storage must be a minimum of 50 feet (Collector) or 100 feet (Arterial) from the back of curb to the visitor call box, or based on the analysis—whichever is greater.
Drive-thru and industrial/warehouse projects must also include specialized queuing analysis. The ITE Transportation and Land Development publication methodology is to be used. Passenger vehicle queue length is 25 feet; truck queue length is 75 feet.
Truck Parking for Industrial Projects
Industrial or warehouse developments must assess truck parking demand using ITE Trip Gen Code 150 and truck parking generation rates from the California Statewide Truck Parking Study (Feb 2022). Calculations should consider a 2.24% rate for warehouse uses and 4.33% for transportation/logistics. The required truck parking must be provided outside any gated areas and clearly shown on the site plan. Coordination with COH Traffic Staff is essential.
Left/Right Turn Storage Analysis
Turn storage bay analysis is required at all study intersections and project driveways. For signalized intersections, use FAST signal timing when available, or the Poisson method with 95% confidence and a 3-minute wait:
Desirable Storage = {N + (z × √N)} × vehicle length
where:
N = [(V × C) / 3600],
V = vehicles/hour,
C = cycle length in seconds,
z = 1.645.
Unsignalized intersections use a uniform arrival rate and 2-minute wait. Vistro and other software tools may be used if results are compared to Synchro HCM or HCS. If calculated storage exceeds the available pocket, the developer must extend it or coordinate with COH for alternative mitigations.
Minimum right-turn lane storage is 150 feet plus standard taper. Passenger vehicles are assumed to be 25 feet long; trucks are 75 feet. Truck storage must be calculated separately and not use Passenger Car Equivalent (PCE).
Major Intersections and Driveways
At intersections of Major Collector or Minor Arterial roads, additional rights-of-way for dual left-turn and right-turn lanes are required per RTC Standard Drawing 201.1. Roundabouts must follow NCHRP Research Report 1043 guidelines.
Driveway regulations include:
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Common driveways are required for similar-use parcels unless otherwise approved.
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No more than two driveways per property frontage. More than two requires City approval.
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Residential developments with 100+ units must have two full-access points.
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For developments generating more than 500 vehicle trips per day:
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Driveways must be spaced 200 feet apart for Major Collectors.
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For Minor Arterials or higher, spacing increases to 300 feet.
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Driveway exceptions in the DCC zoning district are subject to design review.
These guidelines ensure that all projects in the City of Henderson are planned with safe, efficient, and sustainable transportation access in mind, minimizing traffic impacts on the local network and maintaining LOS standards.
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