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                        Road Diet Informational Guide


            
            In This Section
        Other Safety Areas
                Road Diets
                Lighting and Visibility
                                Overview
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                Appendix B – Feasibility Determination Factors, Characteristics, and Sample Evaluative Questions
Factor
			Characteristics
			Sample Evaluative QuestionsRoadway Function and
			Environment
			Actual, Expected, and Desired Primary Function (Access, Mobility, or a Combination of the Two)
				Community Objectives or Goals for the Roadway
				Available Right-of-Way
				Current and Expected Adjacent Land Use
				Jurisdictional Plan or Policy for Conversions
				Jurisdictional Context Sensitive or Complete Street Policy
			What is the primary current, expected, and desired function of the roadway?
				Is the roadway primarily a collector or minor arterial roadway?
				Does the current roadway primarily operate as a "de facto" three-lane cross section?
				Is the goal for the roadway improvement increased safety with somewhat lower mobility?
				Is the right-of-way limited?
				Will the adjacent land use remain relatively stable throughout the design period?
				Will the proposed cross section match the desired function of the roadway?
				Will the answers to the above questions remain the same throughout the design period of the project?
				Does the jurisdiction have a plan or policy related to these types of conversions?
				Does the jurisdiction have a context sensitive or Complete Streets policy that may apply?Crash Types and Patterns
			Type of Crashes
				Location of Crashes
				Number and Location of Pedestrians and Bicyclists
				Parallel Parking  Needs
			Can the crashes that are occurring be reduced with a conversion?
				Will a reduction in speed and speed variability increase safety?
				Are there safety concerns related to parallel parking maneuvers?
				Do pedestrians and bicyclists have safety concerns?Pedestrian and Bike Activity
			Number and Location of Pedestrians
				Number and Location of Bicyclist Use
				Characteristics of Pedestrians and Bicyclists (e.g., Age)
				Bicycle and Pedestrian Friendliness of Roadway
				Cross-section Width
				Parallel Parking Need
				Bus Stop Locations
			What is the pedestrian and bicyclist friendliness of the roadway?
				Do pedestrians and bicyclists have safety concerns?
				Will the addition of a TWLTL assist pedestrians and bicyclists?
				How  will pedestrians and bicyclists interact with parallel parking?
				Can a bike lane be added after the conversion?Overall Traffic Volume and Level of Service
			Total Daily Volume
				Peak-Hour Volume (Morning/Noon/Evening)
				Directional Split
				Intersection and Arterial Level of Service
				Side Street and Driveway Vehicle Delay
				Volume of Frequent-Stop or Slow-MovingVehicles
				Vehicle  Classification
				Signal Timing or Phasing
				Arterial Travel Speeds and Vehicle Delays
				Existence of Turn Lanes
			What is an acceptable increase in minor street or signal- related delay due to the conversion?
				Is a decrease in arterial travel speed of 5 mph or less acceptable?
				What is an acceptable reduction in intersection level of service?
				What level of daily traffic volume and peak hour exists or is expected in the design year?
				Does the signal timing or phasing need to be changed?
				Does the current roadway primarily operate as a "de facto" three-lane cross section?
				What is the potential impact during off-peak hours?Turning Volumes and Patterns
			Number and Location of Turn Volumes and Access Points
				Peak Time Period of Turn Volumes
				Existence of Left-Turn and Right-Turn Lanes
				Design of Access Points and Intersections
				Turn Volume of Frequent-Stop or Slow- Moving Vehicles
				Minor  Street and Access Point Vehicle Delay
				Signal Timing or Phasing
			Does the signal timing or phasing need to be changed or optimized?
				How important is it that right-turning vehicles quickly enter or exit the roadway?
				Do the access point and intersections need to be redesigned (e.g., radii, approach slopes, location)?
				Are right-turn lanes needed at particular locations?
				Does the proposed marking allow the design vehicle (e.g., tractor-trailer) to turn properly?
				What is an acceptable increase in minor street vehicle delay and left-turning vehicle delay?
				Does the current roadway primarily operate as a "de facto" three-lane cross section?Frequent-Stop and/or
			Slow-Moving Vehicles
			Volume, Location, and Time of Frequent-Stop and/or Slow-Moving Vehicles
				Type, Design (Length, Width, Turning Radius, etc.) and Speed of Vehicles
				Arterial Travel Speeds and Vehicle Delays
				Level of Enforcement for Proper TWLTL Use (i.e., No Passing Allowed)
			What is the acceptable delay with respect to frequent- stop and/or slow-moving vehicles?
				Can these vehicles turn properly at the access points and intersections?
				Can passing  prohibitions be feasibly enforced?
				Are there locations for pull-outs for these vehicles?
				Can some or all of the stop locations for the frequent-stop vehicles be combined?
				What are the potential peak and off-peak impacts?Weaving, Speed, and
			Queues
			Signal Timing or Phasing
				Number  of Existing Lane Changes
				Turn Volume and Location
				Arterial Travel Speeds and Vehicle Delays
				Level of Enforcement for Proper TWLTL Use (i.e., No Passing Allowed)
				Number  and Location of Turn Volumes and Access Points
				Peak Time Period of Turn Volumes
				Existence of Left-Turn and Right-Turn Lanes
				Design of Access Points and Intersections
				Turn Volume of Frequent-Stop or Slow- Moving Vehicles
				Minor  Street and Access Point Vehicle Delay
				Queue Length
				Number  of Speeders
			Does the signal timing or phasing need to be changed or optimized?
				How important is it that right-turning vehicles quickly enter or exit the roadway?
				Do the access point and intersections need to be redesigned (e.g., radii, approach slopes, location)?
				Are right-turn lanes needed at particular locations?
				What is an acceptable increase in minor street and left- turning vehicle delay?
				Is a decrease in arterial travel speed of 5 miles per hour or less acceptable?
				What is an acceptable change in queues?
				Are there safety concerns related to weaving?
				Can no passing be enforced?
				Can drivers  be educated about proper use of TWLTL?
				Is a reduction in speeders and speed variability preferred?
				Can all the old markings be completely removed?
				Does the current roadway primarily operate as a "de facto" three-lane cross section?Right-of-Way Availability, Cost, and Acquisition Impacts
			Available Right-of-Way
				Cost of Right-of-Way
				Existence of Left-Turn and Right-Turn Lanes
				Design of Access Points and Intersections
				Number  of Properties Needed and Environmental Impacts (e.g., Tree Removal)
				Cross Section Width
				Parallel Parking  Needs
			Is the right-of-way limited?
				Will the cost of right-of-way acquisition be significant?
				Do the access point and intersections need to be redesigned (e.g., radii, approach slopes, location)?
				Are right-turn lanes needed at particular locations?
				What is necessary in the cross section (e.g., bike lane, parallel parking, etc.)?**General Characteristics**Parallel Roadways
			Roadway Network Layout
				Volume and Characteristics of Through Vehicles Diverted
				Impact of Diversion on Parallel Roadways
			Is a decrease in arterial travel speed of 5 miles per hour or less acceptable?
				Does the signal timing or phasing need to change or be optimized?
				Will conversion divert through vehicles to parallel roadways?
				Is it possible to avoid or reroute the diverted traffic?
				What is the impact on the parallel roadway environment?Offset Minor Street
			Intersections
			Volume and Time of Left Turns
				Queue Lengths
				Distance between Minor Street Approaches
			Do left turns occur into both minor street and access point approaches at a similar time?
				Are the left-turn volumes significant?
				Will the left-turn volumes produce queues in the through lanes of a three-lane roadway?Parallel Parking
			Parallel Parking  Needs
				Number  of Parking Maneuvers
				Operational and Safety Impacts of Parallel Parking
				Design of Existing or Proposed Parallel Parking
			Does parallel parking exist?
				How many parking maneuvers occur during peak travel times?
				What are the safety and delay concerns related to parallel parking maneuvers?
				Is it possible to design these spaces for easy entry or exit (i.e., to minimize delay)?
				Will it be necessary to reduce the number of parking spaces?
				Does parallel parking reduce the ability of vehicles to turn in and out of minor streets and access points?Corner Radii
			Design of Access Points and Intersections
				Number  and Location of Turn Volumes and Access Points
				Peak Time Period of Turn Volumes
				Existence of Left-Turn and Right-Turn Lanes
				Turn Volume of Frequent-Stop or Slow- Moving Vehicles
				Minor  Street and Access Point Vehicle Delay
			How important is it that right-turning vehicles quickly enter or exit the roadway?
				Do the access points and intersections need to be redesigned (e.g., radii, approach slopes, location)?
				Are right-turn lanes needed at particular locations?
				Does the proposed marking allow the design vehicle (e.g., tractor-trailer) to turn properly?
				Do parallel parking spaces need to be removed to allow proper turning?At-Grade Railroad
			Crossing
			Volume, Location, and Time of Train Crossing
				Length of Crossing Train
				Delay  Impacts of Train Crossing
				Queue Impacts of Train Crossing
				Total Daily Vehicle Volume
				Peak-Hour Vehicle Volume  (Morning/Noon/ Evening)
				Directional Split of Vehicles
			Do trains cross during peak travel periods?
				What is the typical delay from a train crossing?
				Is double the current queue length (with four-lane undivided cross section) at a railroad at-grade crossing acceptable?
				Is there a nearby parallel at-grade intersection where impacts may need to be mitigated?Adapted from Knapp, Welch, and Witmer, 1999.
      
  Book traversal links for Appendix B – Feasibility Determination Factors, Characteristics, and Sample Evaluative Questions
      ‹ Appendix A – Road Diet Safety Assessment Studies
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