CNU Summit 2009 RDI

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  • Cities are looking for additional tools to help them plan for multi-modal transportation systems. Even the most sophisticated travel demand models do not estimate and assign non-motorized traffic to the transportation network. Recent national studies in the development of multimodal level-of-service (LOS) techniques have not been well-received by practicing planners and engineers who are focused on pedestrian and bicycle systems . Planners and engineers are seeking new measures to better illustrate the range of non-motorized system connectivity, to help prioritize multi-modal plan projects. Rather than focus on estimating measures on non-motorized travel demand , this study focuses on measuring non-motorized system performance in the form of network connectivity
  • Link/Node ratio – National studies estimate 1.4 as the connectivity threshold for “walkable” neighborhoods/network. Route Directness Ratio – the closer to 1.0, the greater the connectivity. Also consider additional GIS measures that expand on baseline measures, measures that require greater database development and analytical techniques. Sidewalk Coverage or More Detailed Walkability Ratings Bike ability Scoring Affects of Pedestrian and & Bicycle System plan priority connectors Connectivity scoring could be input in (1) Pedestrian and Bicycle system plan prioritization and (2) refined Concurrency policy/program
  • Network Connectivity – Street Design – Is only one of several important factors in transportation-efficient land use planning, it’s the smaller of the 3 D factors affecting person miles traveled. Together quality land use mix, density and a well-connected street/pedestrian system yields significantly lower VMT and GHG per capita. Distinguishing measures of DESIGN include average block size, % 4-way intersections and % sidewalk coverage. In reality, while strong indicators, all three measures are only proxies of connectivity. There is a need for a uniform and direct measure of connectivity – land use/transportation relationship.
  • Testing Olympia GIS Data for Intersection Density Metrics. As proxies , intersection density metrics can be mapped, but are difficult to then illustrate the benefit of planned, non-motorized system improvements; nor do they reflect the actual system network quality of walking and bicycle travel.
  • Composite Accessibility Indices (layering analysis) are helpful in identifying pedestrian or bicycle system improvement priorities, but do not provide measure of non-motorized system connectivity nor baseline system measures to gauge plan success and progress. The RDI can supplement composite accessibility measures in establishing Plan priorities, plus quantify system connectivity.
  • Similar to Bicycle network, Transpo RDI Tool used to calculate pedestrian connectivity between tax lots and LRT station. Weighted Distance calculation in ESRI’s Network Analyst estimating Bicycle Route Choice: distance and existing vs. missing sidewalks with travel impedance. Additional variables can be added to route choice calculator: pedestrian environment (walkability factors and amenities), vehicle travel lanes, vehicle volume, and vehicle speed.
  • Similar to Bicycle network, Transpo RDI Tool used to calculate pedestrian connectivity between tax lots and LRT station. Weighted Distance calculation in ESRI’s Network Analyst estimating Bicycle Route Choice: distance and existing vs. missing sidewalks with travel impedance. Additional variables can be added to route choice calculator: pedestrian environment (walkability factors and amenities), vehicle travel lanes, vehicle volume, and vehicle speed.
  • Slide illustrates the RDI calculation for a select O-D pair of dwellings within a hierarchical (non-grid, cul-de-sac focused) neighborhood.
  • Slide illustrates the RDI calculation reflecting enhanced neighborhood connections.
  • Testing Olympia GIS Data for RDI at the neighborhood and city-wide scale: the challenge .
  • Four examples of applied use – Transpo RDI Desktop
  • In Washington State, Concurrency/Growth Management/Sustainability policy direction – seeking multi-modal quality-of-service (QOS) measures. System-wide RDI scoring for pedestrian and bicycle connectivity surpasses other system “proxy” measures.
  • NLR not very helpful in analyzing Plan improvements when street base is already connected with few dead-ends
  • Pedestrian Access to Light Rail Transit
  • Seattle DOT has prepared a Pedestrian Master Plan, with several arterial crossing recommendations, acknowledging sidewalk and pedestrian bridge projects within the LRT station area. Plan developed concurrent with LRT line and station area planning.
  • ESRI Network Analyst used to create Pedestrian Network, using City’s centerline file and PMP profile- pedestrian facility types
  • Baseline conditions note poor pedestrian connectivity in southwest LRT station area – very hilly terrain .
  • Transpo RDI Tool used to model importance of “Hanford Steps.” Significant connection, remaining “poor” RDI parcels subject to large tax lots and missing internal (private connections).
  • Exercise illustrates strength of Transpo RDI Tool use: Testing RDI scores of individual pedestrian plan projects, identifying and ranking priority LRT station area access improvements with a consistent measurement tool Ability to weight project RDI scoring with land use – socio-economic profile (e.g. low income, transit-dependent residents) Integrated non-motorized and LRT planning – helps “train the Planner’s eye” for LRT accessibility issues and solutions.
  • Transpo RDI Tool used to model importance of “Hanford Steps.” Significant connection, remaining “poor” RDI parcels subject to large tax lots and missing internal (private connections).
  • Bike Access to Light Rail Transit
  • Initial steps to prepare base GIS files for RDI calculation to measure bicycle access to LRT stations.
  • Seattle DOT had prepared a Bicycle Master Plan, with several route enhancement recommendation within the LRT station area. Plan pre-dated LRT line and station area development. ESRI Network Analyst used to create Bicycle Network, using City’s centerline file and BMP route profile- bicycle facility types
  • Transpo RDI Tool used to calculate bike connectivity between tax lots and LRT station. Weighted Distance calculation in ESRI’s Network Analyst estimating Bicycle Route Choice: distance and route slope, varying travel impedance by bike facility type. Additional variables can be added to route choice calculator: vehicle travel lanes, vehicle volume, and vehicle speed. METRO Portland is finalizing bicycle route choice model parameters and variables for future use.
  • Base year RDI score for tax parcels calculated using baseline street system.
  • Impact of Seattle’s BMP: new bicycle lane on busy arterial. Significant enhancement to bicycle – LRT access in SE quadrant of station area.
  • Plotted “Delta” between Base Year and Impact of Bicycle Master Plan.
  • Even with BMP enhancements, there remains relatively poor connectivity between NE and SW neighborhoods and the LRT station. Transpo RDI Tool used to test additional Bicycle Boulevard enhancement.
  • Exercise illustrates strength of Transpo RDI Tool use: Supplemental to long-range non-motorized plans which pre-date LRT route and station area plans – helps identify new or modified project priorities Integrated non-motorized and LRT planning – helps “train the Planner’s eye” for LRT accessibility issues and solutions.
  • Impact of Seattle’s BMP: new bicycle lane on busy arterial. Significant enhancement to bicycle – LRT access in SE quadrant of station area.
  • Building GIS database to measure “crow flight between potential origin-destination pairs (example: tax lot-to-tax lot). Base values reflect averaged RDI for each tax lot origin, with destinations originally set at a one-half mile maximum walking distance.
  • RDI re-calculated based on added shared-use path connectors
  • Note RDI measures for tax lots in relation to adjacent block length and cul-de-sac length
  • A delta plot is easily mapped to illustrate the tax lots which directly benefit from improved access, or connectivity.
  • Building GIS database to measure “crow flight between potential origin-destination pairs (example: tax lot-to-tax lot). Base values reflect averaged RDI for each tax lot origin, with destinations originally set at a one-half mile maximum walking distance.
  • RDI re-calculated based on added shared-use path connectors
  • Pedestrian Access to Commuter Rail
  • New Sounder Station in Lakewood, Washington Commuter Rail route to Tacoma and Downtown Seattle Non-Motorized Plan identifies Interstate Freeway and Railroad Over-crossing enhancements, major impediments to bicycle and pedestrian travel and access to new Sounder Station.
  • Transpo RDI Tool used to model “Baseline” or existing access/connection from neighboring land use to commuter rail station. Significant rail and freeway barrier to non-motorized connectivity, much of commuter station catchment area RDI is Fair to Poor.
  • Transpo RDI Tool used to model I-5 Over-crossing enhancements. Significant improvement to non-motorized RDI south of I-5.
  • Transpo RDI Tool used to model Sounder railroad Over-crossing and connection enhancements. Significant improvement to are-wide RDI.
  • CNU Summit 2009 RDI

    1. 1. measuring Transportation Connectivity by Route Directness Index using * * Trademarks provided under license from ESRI. 2009 Transportation Summit – Portland, Oregon
    2. 2. Background Policy Issues <ul><li>Complete Streets Policy </li></ul><ul><li>Concurrency Program Refinements </li></ul><ul><li>VMT and GHG per Capita Reduction </li></ul><ul><li>Multi-Modal Level-of-Service (LOS) </li></ul><ul><li>Street Connectivity Policies </li></ul><ul><ul><li>Connectivity between new/existing developed lands </li></ul></ul><ul><ul><li>Non-motorized public accessways and limiting cul-de-sacs </li></ul></ul><ul><ul><li>Grid-based standards for streets (500 feet ) and Non-motorized (330 feet) – emphasis on smaller block lengths </li></ul></ul><ul><ul><li>Developing connectivity metrics </li></ul></ul>Cities are looking at a host of transportation, land use, energy, environmental and sustainability policy issues and considering new measurement techniques:
    3. 3. Testing Connectivity Metrics <ul><li>Link / Node Ratio </li></ul><ul><li>Intersection Density </li></ul><ul><li>% 4-Way Intersections </li></ul><ul><li>Route Directness Ratio </li></ul>1990’s Hierarchical Network 1990’s Hierarchical Network 1950’s Grid Network A B C D A B C D 261 / 146 = 1.79 107 40 % .74 158 / 143 = 1.10 93 20 % .44 (Miles on Perimeter Arterial) 0.4 2.7 Connectivity measurements in small subareas are straight-forward; but what about city-wide?
    4. 4. Achieving VMT per Capita Reduction - 4 % - 2 % - 5% Measures of connectivity help indicate transportation-efficient land uses that yield lower VMT and GHG per capita Research conducted in Seattle area by C. Lee and Anne Moudon (University of Washington), 2006: Quantifying Land Use and Urban Form Correlates of Walking
    5. 5. Intersection Density Intersection Density 4-Way Intersection Density GIS mapping techniques can illustrate city-wide measures of intersection density but have difficulty illustrating “Plan” benefits Link-Node, Intersection Density and Walkscore Measures are only Proxies for connectivity – RDI is a direct measure of connectivity
    6. 6. Composite Accessibility Indices Can help identify and prioritize plans, but miss the important measure of system connectivity and notable gaps.
    7. 7. Defining RDI <ul><li>Define Route Directness Index </li></ul><ul><li>The Route Directness Index (RDI) can be used to quantify how well a street network connects destinations. </li></ul><ul><li>The RDI can be measured separately for motorized and non-motorized travel, taking into account non-motorized shortcuts, such as paths that connect cul-de-sacs, and barriers such as highways and streets that lack sidewalks. </li></ul><ul><li>The RDI is calculated by dividing direct travel distances by actual travel distances. For example, if streets are connected, have good sidewalks, and blocks are relatively small, people can travel nearly directly to destinations, resulting in a high index. If the street network has many unconnected dead-ends and blocks are large, people must travel farther to reach destinations, resulting in a low index. </li></ul>
    8. 8. RDI Credits <ul><li>Jennifer Dill, Portland State University </li></ul><ul><ul><li>Research – Connectivity Metrics </li></ul></ul><ul><li>Victoria Transport Policy Institute </li></ul><ul><ul><li>Policy – Connectivity Metrics </li></ul></ul><ul><li>Charlier & Associates & Otak Intl. – CNU </li></ul><ul><ul><li>Practice </li></ul></ul><ul><li>Others </li></ul>
    9. 9. RDI Example: Pre Neighborhood Connector Route Directness Index can better illustrate “before-and-after” Plan improvements Existing Shared-Use Path Route Directness Index Crow Flight Walk Distance RDI / = 1850 ft 1850 ft RDI: .20 .20 375 ft 375 ft
    10. 10. RDI Example: Post Neighborhood Connector Route Directness Index can better illustrate “before-and-after” Plan improvements Existing Shared-Use Path Route Directness Index Crow Flight Walk Distance RDI = New Neighborhood Connectors / 375 ft 375 ft RDI: .83 .83 450 ft 450 ft
    11. 11. RDI – GIS Focal Exam Testing RDI on a larger, city-wide scale is the challenge Poor Good
    12. 12. Examples Using RDI Desktop TM <ul><li>Access to Commuter Rail Station </li></ul><ul><li>Bike Access to LRT Station </li></ul><ul><li>Pedestrian Access to LRT Station </li></ul><ul><li>Neighborhood Design / Growth Management </li></ul><ul><li>Non-Motorized Concurrency and Quality of Service </li></ul>
    13. 13. Growth Management: Non-Motorized Concurrency and Quality of Service <ul><li>Using RDI Desktop to demonstrate functional implementation of a Master Plan area: </li></ul><ul><li>Measuring connectivity with & without exclusive pedestrian routes </li></ul><ul><li>RDI Measure: Neighborhood Connectivity </li></ul>1
    14. 14. Planned Neighborhood <ul><li>Neighborhood design: </li></ul><ul><ul><li>Mixture of villa plot size </li></ul></ul><ul><ul><li>Neighborhood centers </li></ul></ul><ul><li>Maximized public realm for non-motorized connectivity through: </li></ul><ul><ul><li>Quality street pedestrian zone </li></ul></ul><ul><ul><li>Connecting exclusive pedestrian routes, and park/open spaces </li></ul></ul>
    15. 15. Neighborhood RDI Score <ul><li>Measured without Pedestrian connections </li></ul><ul><li>Fair RDI scores </li></ul>Poor Fair Excellent Parcel RDI Desktop TM Metric Parcel Average RDI Score: Fair .65
    16. 16. Neighborhood RDI Score <ul><li>Measured with Pedestrian connections </li></ul><ul><li>Good-Excellent RDI scores </li></ul>Poor Fair Excellent Parcel RDI Desktop TM Metric Parcel Average RDI Score: Good .73 RDI scoring can be used to establish non-motorized concurrency measures and thresholds, used to evaluate future land development plans for policy compliance
    17. 17. Comparative RDI Scoring <ul><li>RDI Score Difference: With and Without Pedestrian connections </li></ul>Parcel RDI Desktop TM Metric Parcel Plots that benefit significantly by Pedestrian connectivity
    18. 18. Intersection Density Scoring <ul><li>Intersection Density Score Without SUPs </li></ul>Poor Fair Excellent Average Density Score: Poor 68
    19. 19. Intersection Density Scoring <ul><li>Intersection Density Score With SUPs </li></ul>Fair Average Density Score: Good 142 Poor Excellent
    20. 20. Link-Node Scoring <ul><li>Node-Link Score Without SUPs </li></ul>Link-Node Ratio: 1.66
    21. 21. Link-Node Scoring <ul><li>Node-Link Score With SUPs </li></ul>Link-Node Ratio: 1.67
    22. 22. Seattle’s Mt. Baker Link LRT Station Example <ul><li>RDI Measure: Pedestrian Access to LRT Station </li></ul>
    23. 23. Establish GIS Database <ul><li>Study area </li></ul><ul><li>Light rail line </li></ul><ul><li>Street centerline </li></ul><ul><li>Parcel data </li></ul>
    24. 24. Create Pedestrian Network <ul><li>Create Pedestrian Network </li></ul><ul><li>Illustrate Importance of “Hanford Steps” </li></ul>
    25. 25. Calculate Base Year RDI <ul><li>Study Parcels (2,000 foot radius buffer from LRT station) </li></ul><ul><li>Pedestrian RDI to Mt. Baker Station </li></ul><ul><li>Baseline Conditions (assumes no Hanford Steps) </li></ul><ul><li>RDI Average = 0.67 </li></ul>Parcel RDI Desktop TM Metric Station Average RDI Score: Fair .67 Poor Good
    26. 26. Calculate PMP RDI <ul><li>Pedestrian RDI to Mt. Baker Station </li></ul><ul><li>RDI Impact of Hanford Steps </li></ul>Poor Good Parcel RDI Desktop TM Metric Station Average RDI Score: Good .72
    27. 27. Estimate RDI Enhancement <ul><li>Pedestrian RDI to Mt. Baker Station </li></ul><ul><li>Difference between Baseline RDI and Hanford Steps RDI </li></ul><ul><li>Baseline: 58% of parcels above RDI 0.65 threshold. </li></ul><ul><li>Steps RDI: 73% of parcels above threshold. </li></ul><ul><li>Additional 40 more parcels. </li></ul>RDI scoring can be used to sharpen plan priorities, particularly as federal and state funding becomes more competitive
    28. 28. Intersection Density <ul><li>Without link </li></ul><ul><li>Average: 296 intersections per mi 2 </li></ul>Poor Good Average Density Score: Fair 296
    29. 29. Intersection Density <ul><li>With project </li></ul><ul><li>Average: 302 intersections per mi 2 </li></ul><ul><li>Marginal increase </li></ul>Average Density Score: Fair 302 Poor Good
    30. 30. Seattle’s Beacon Hill Link LRT Station Example <ul><li>RDI Measure: Bike Access to LRT Station </li></ul>
    31. 31. Import GIS Database <ul><li>Study area </li></ul><ul><li>Light rail line </li></ul><ul><li>Street centerline </li></ul><ul><li>Parcel data </li></ul>
    32. 32. Create Bicycle Network <ul><li>Create bike network </li></ul><ul><li>Bicycle Master Plan – existing conditions (2004) </li></ul>
    33. 33. Route Choice Analyses <ul><li>Route Directness Index </li></ul><ul><li>Weighted Distance based on bicycle network characteristics </li></ul>
    34. 34. Calculate Base Year RDI <ul><li>Study parcels (one-mile link distance) </li></ul><ul><li>Routes from parcels to Beacon Hill Station </li></ul><ul><li>Existing Conditions (2004) </li></ul>Poor Good
    35. 35. Calculate BMP RDI <ul><li>Added Bike Lanes noted in Bicycle Master Plan (BMP) </li></ul>Poor Good
    36. 36. Estimate RDI Enhancement <ul><li>Difference between Existing RDI and BMP RDI </li></ul>
    37. 37. Alternatives Analysis <ul><li>Testing new Bicycle Boulevard project to improve E-W connectivity </li></ul>Poor Good BMP oriented mostly north-south (arterials)… … instead of to LRT sta. RDI scoring can be used to identify supplemental master plans, using detailed route-choice analyses that integrate walkability and bicycle compatibility indices
    38. 38. RDI Comparison <ul><li>Difference between BMP RDI and RDI with added Bike Boulevard project </li></ul>
    39. 39. Connectivity to LRT Baseline Measure: Bicycle Master Plan Plan Refinement: New Bicycle Boulevard Bicycle System Connectivity Scores Project Impact: Improved Connectivity Poor Good Poor Good
    40. 40. Non-motorized System Plan Evaluation <ul><li>RDI Measure: Pedestrian Network Connectivity </li></ul>
    41. 41. Existing Conditions Shared-Use Path Connections Average RDI Score: Poor / Fair .58
    42. 42. New Shared-Use Paths Shared-Use Path Connections Average RDI Score: Fair / Good .66 14 % improvement
    43. 43. RDI – “Before & After” Shared-Use Path Connections Sensitive to Block Length Sensitive to Cul-de-Sac Length 305 ft 330ft RDI scoring is sensitive to urban design principles – because it directly measures connectivity
    44. 44. RDI – “Before & After” Delta Shared-Use Path Connections
    45. 45. Link-Node: Before Link-Node Ratio: 1.45 Nodes 74 Links 107 Ratio 1.45 Shared-Use Path Connections
    46. 46. Link-Node: After Shared-Use Path Connections Link-Node Ratio: 1.53 5.5 % improvement Nodes 92 Links 141 Ratio 1.53
    47. 47. Lakewood Sounder Commuter Rail Station Example <ul><li>RDI Measure: Access to Commuter Rail Station </li></ul>
    48. 48. Lakewood’s NMTP New Pedestrian-Bicycle Connections RR Over-crossing I-5 Over-crossing
    49. 49. RDI - Baseline <ul><li>Testing RDI: Land Use – to Sounder Station </li></ul><ul><li>Land Use (building structures) within One-Mile Radius </li></ul><ul><li>“ Baseline” = Existing Pedestrian System Connectivity </li></ul>Poor Fair Good
    50. 50. RDI – After I-5 Crossing <ul><li>Impact of I-5 Over-Crossing Improvements </li></ul><ul><li>Addition of Sidewalks and Bike Lanes </li></ul>Poor Fair Good
    51. 51. RDI – After RR Crossing <ul><li>Impact of New Railroad Over-Crossing </li></ul><ul><li>Exclusive Non-Motorized Facility </li></ul>Poor Fair Good
    52. 52. Why Use Route Directness Index <ul><li>RDI metric can enumerate important quality of connectedness, a primary factor (along with land mix and density) in urban transportation sustainability by: </li></ul><ul><ul><li>Directly measuring street / pathway connections, rather than proxy measures, and </li></ul></ul><ul><ul><li>Mapping spatial variation in land use connectivity </li></ul></ul><ul><li>RDI calculates numerical metrics to evaluate the quality of a connection between an origin location and one or more destinations. These metrics can be mapped thematically at the origin location to highlight areas of connectivity quality (range, good-bad). </li></ul><ul><li>Using these metrics, before and after analyses can be performed to quantify and locate the impacts of improved connections (especially non-motorized connections), establishing Comparative RDI Benefit to Existing Land Use </li></ul>
    53. 53. Route Choice Modeling <ul><li>Non-motorized system quality, or levels and types of obstacles (impedances) are important factors to consider in walking and cycling route choice sub-models </li></ul>
    54. 54. How Can RDI Desktop TM Help? <ul><li>Street Design Policy Implementation – measurable guidelines </li></ul><ul><li>Establish Non-motorized Neighborhood Connectivity Standards </li></ul><ul><ul><li>Design guide thresholds for neighborhood planning site plan review – non-motorized concurrency </li></ul></ul><ul><li>Non-Motorized Plan Strategic Prioritization </li></ul><ul><ul><li>Measure current networks - target critical non-motorized connections </li></ul></ul><ul><ul><li>Minimizing expensive and unnecessary data collection </li></ul></ul><ul><ul><li>Help expedite Draft Non-motorized Plan project identification and priorities </li></ul></ul><ul><ul><li>Consistently evaluate and rank multi-modal projects for federal Transportation Enhancement Program grant applications </li></ul></ul><ul><li>Critical Plan Priority Analysis and Ranking – consistent and robust technique (with other sub-models) to measure important: </li></ul><ul><ul><li>Neighborhood Connectors </li></ul></ul><ul><ul><li>Transit Access Connectors </li></ul></ul><ul><ul><li>Urban Boulevard Crossings </li></ul></ul>
    55. 55. Contact <ul><li>Andy Mortensen  </li></ul><ul><li>               WHAT TRANSPORTATION CAN BE </li></ul><ul><li>[email_address] </li></ul><ul><li>503.313.6946 </li></ul><ul><li>www.transpogroup.com </li></ul><ul><li>Abu Dhabi | Kirkland | Seattle | Boise </li></ul>* Trademarks provided under license from ESRI. *

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