Traffic Impact Study
A Traffic Impact Study (TIS) may be required to evaluate the effect a proposed development will have on the
Countys existing traffic system and may require specific improvements to mitigate the impact on public roads with
the approval of NCDOT or applicable municipality.
A. Requirement Thresholds. A TIS is required for any proposed development that meets any of the following
(1) Any residential subdivision proposing 100 or more lots/units.
(2) Any residential or nonresidential development proposed to generate an average daily traffic count
of 1,000 plus vehicles per day or 100 plus trips during peak traffic hour. This traffic count must be
based on the latest version of the Institute of Transportation Engineers (ITE) Trip Generation
(3) Any expansion or change to an existing or proposed residential or nonresidential development that
would generate an additional 1,000 plus vehicles per day or 100 plus trips during peak traffic hour.
This traffic count must be based on the latest version of the Institute of Transportation Engineers
(ITE) Trip Generation Manual.
Notwithstanding the above, a TIS shall not be required if the property to be developed has been the subject
of a TIS within the previous three (3) years and the projected trip generation of the newly proposed
development is equal to or less than the previous TIS preformed and the trip distribution has not
B. Traffic Impact Study (TIS) Guidelines.
(1) Any TIS, whether required or voluntarily, must be prepared by a licensed engineer and submitted
as part, or as a condition, of the master plan approval or site plan approval. Prior to conducting the
TIS, the developer must meet with County Staff, the Technical Review Committee, and NCDOT to
identify certain assumptions that shall be addressed in the TIS.
(2) An executive summary shall be provided with the TIS outlining the following: (1) detailed
description of the proposed development, (2) number of access points proposed and studied, (3)
existing and future Level of Service (LOS) for studied intersections and road segments including
the LOS at the time of build-out, (4) existing traffic counts for road(s) and intersection(s) studied
and dates/times counts were conducted, (5) AM and PM Peak Hour Trips, (6) Average Daily Trips
created by the development at build-out, (7) Existing Traffic Accident Counts, and (8) any
(3) The TIS shall address the: (1) proposed land use, (2) site access and site distances at all proposed
access points, (3) impacts on the transportation system from the proposed development, and (4)
physical improvements or enforceable management strategies to mitigate negative impacts.
(4) The TIS shall take into consideration proposed/planned NCDOT roadway improvement projects as
identified on the Metropolitan Transportation Improvement Program (MTIP), State Transportation
Improvement Program (STIP), the French Broad River Metropolitan Planning Organization Long
Range Plan, and the Comprehensive Transportation Plan.
(5) The TIS shall identify the improvements necessary to maintain Level of Service (LOS) D for roads
and intersections as defined in the Highway Capacity Manual.
(6) Recommended improvements within the TIS shall take into account the Traffic Impact Study
Improvement Requirements listed in §42-136 (Traffic Impact Study) (C).
Traffic Impact Study (TIS) Improvement Requirements. The approving authority for all subdivisions
requiring a TIS may require additional mitigation standards or offsite improvements provided when
improvements are acceptable by NCDOT or applicable municipality. However, a TIS shall not be utilized
as a means for the County to require the party developing the property to make needed transportation
improvements remote from and not affected by the property for which the TIS is submitted, nor shall
identified deficiencies in LOS automatically preclude approval of the proposed development.
(1) Left Turn Lane, Right Turn Lane, and/or Right Turn Taper: Based on requirements of the NCDOT
Policy on Street and Driveway Access to North Carolina Highways or other NCDOT standards.
(2) Additional Right-of-Way: If a subject development falls along a road projected to be widened by
NCDOT or an adopted County plan, additional right-of-way along the developments road
frontage shall be dedicated as deemed acceptable by NCDOT.
(3) Offsite Improvements: If a road segment or intersection is currently performing at LOS-D or better
and is projected to perform at LOS-E or F at the time of build-out, improvements must be made to
maintain the road segment or intersection at LOS-D. If a road segment or intersection is currently
performing at LOS-E or F and is projected to continue to perform at LOS-E or F at the time of
build-out, the TIS shall demonstrate how an LOS-D could be achieved and also specify what
improvements must be made to ensure that the road segment or intersection is not degraded any
further than the current levels. The County may require improvements be made to preserve the
(4) Other Necessary Improvements: Additional improvements may be required based on the TIS
recommendations related to topographic/environmental conditions, sight distance, street offsets,
conflicting movements, existing traffic accident counts, circulation, and other potential traffic
issues resulting from the proposed development. Additionally, the approving authority may
determine that additional improvements are necessary to ensure the safety and welfare of the
Countys citizens and travelers.