Design & Construction Standards

Traffic and Safety Resources

Traffic Impact Analysis (TIA)

Purpose

The purpose of Traffic Impact Analysis (TIA) is to identify the impact a development will have on traffic congestion and safety and provide a basis for determining what steps the developer needs to take to mitigate those impacts.

Process

Property owners who construct new approaches, change existing approaches, or change land use on existing approaches to state roads must obtain driveway permits from the Alaska Department of Transportation and Public Facilities (DOT&PF). If the new or changed property is projected to generate more than 100 additional vehicle trips per hour during any hour of the day or when DOT&PF determines it may detract from road safety, a TIA is required. Property Owners must apply for driveway permits from the appropriate regional DOT&PF Right-of-Way office. Right-of-Way will be their primary point of contact throughout the driveway permit and TIA process.

If a TIA is required, regional DOT&PF Traffic & Safety staff will work with property owners to define specific requirements of the TIA and guide them toward successful TIA completion. Both the owner and the owner’s engineer need to meet with DOT&PF regional Traffic & Safety and Right-of-Way in a pre-analysis meeting to discuss the content of the TIA. As the analysis progresses, DOT&PF may request clarification or further analysis to give adequate consideration to risks to the traveling public. Property owners must submit draft TIAs, address DOT&PF comments, and then submit a final TIA. The final TIA must satisfy all DOT&PF requirements before a permit will be granted.

If a development that accesses a municipal road generates downstream traffic impacts on a state highway, and those impacts meet TIA thresholds, the municipality should complete or require the owner to complete a TIA.

TIA Content

The TIA must address the information and calculations identified in the TIA Requirement Checklist. DOT&PF may require additional detail to address location specific conditions.

Legal Requirements

Alaska Statute AS 19.05.040 Powers of Department authorizes DOT&PF to control access to highways and regulate roadside development.

Article 2 of the Alaska Administrative Code, Driveway and Approach Road Permits, provides regulations pertaining to required permits.

Contacts

Design & Construction Standards

Contact D&ES Webmaster

3132 Channel Dr.,
P.O. Box 112500
Juneau, AK 99811-2500
Phone: (907)451-2283
Fax: (907)465-3124

Pam Golden, P.E.
Statewide Traffic & Safety Engineer

Traffic Impact Analysis. Include the following:
	Development Information
			Development description
			Land use intensity including square footage, types of land use, employees, etc.
			Proposed zoning changes or zoning variances
			Construction year, opening year, projected year for full buildout
			Map of the development, including traffic circulation and parking area
			Sight distance evaluation from access points
			Alternatives to the proposed location
	Project Area Background
			Surrounding land zoning
			Surrounding land uses and site land use
			Adjacent development
			Traffic improvements already funded, programmed, or planned
			Other planned developments
	Data Requirements
			Map of the study area street network
			Peak hour intersection turning movement counts for all key intersections
			Daily volume counts for all streets and roadways in the study area
			Number of lanes on the streets in the study area
			Intersection geometry information for all key intersections
			Traffic signal phasing and timing information for all key intersections
			5 year crash history within the study area
			Sidewalks and other pedestrian facilities
			Bike lanes and other bicycle facilities
			Transit operation and facilities including pullouts, frequency of service and utilization
	Traffic Forecasting
			Projected traffic to be generated by the development (Use the ITE Trip Generation Manual, latest version)
			Projected trip distribution, turning movements, and rationale for determining same
			Projected total traffic for the design year (base traffic + site traffic) at all Key Intersections and route segments within the study area
			Trip generation from other planned developments
	Traffic Analysis
			Baseline LOS calculations for all Key Intersections and Key Road Segments (For LOS computations, use the TRB Special Report 209, Highway Capacity Manual, latest version)
			No- Build Alternative— Without Development
				Projected LOS calculations for all key intersections and key road segments for the opening date or the design year, as required
				Vehicle queue lengths (95th percentile) and available storage
				Pedestrian considerations, including applicable school walking routes
				Bicycle considerations
				Transit considerations
				Safety considerations for all Key Intersections and key road segments
			Build Alternative— With Development
				Projected LOS calculations for all key intersections and key road segments for the opening date or the design year, as required
				Vehicle queue lengths (95th percentile) and available storage
				Pedestrian considerations, including applicable school walking routes
				Bicycle considerations
				Transit considerations
				Safety considerations for all Key Intersections and key road segments
	Summary
		Summary of impacts
	Mitigation
			Mitigation measure alternatives to address capacity, delay, pedestrian, bicycle, transit and safety issues caused by or exacerbated by the development
			Proposed mitigation measures
			Proposed improvements to development parking and circulation routes
			Mitigation measure affects (include projected LOS calculations and / or crash reduction factors as applicable)
			Conclusion

Typical Reporting Requirements:
	Submit electronic data/files compatible with Microsoft Office products, latest release of Autodesk AutoCAD, Trafficware Synchro Studio 7, and MacTrans HCS+