Statewide Shoulders Study Task MPD 059-14 Executive Summary August 2015 Prepared by Table of Contents Study Overview .........................................................................................................................................................1 Purpose and Need ......................................................................................................................................................1 Technical Advisory Committee (TAC) .........................................................................................................................2 Stakeholder Outreach ...............................................................................................................................................3 Identification and Prioritization Methodology............................................................................................................4 Methodology to Identify Shoulder Improvements on Two-Lane Highways ....................................................................4 Methodology to Identify Shoulder Improvements on Multilane Highways .....................................................................6 Shoulder Improvements on Two-Lane Highways ......................................................................................................8 Flagstaff District .........................................................................................................................................................9 Globe District ...........................................................................................................................................................14 Holbrook District ......................................................................................................................................................20 Kingman District ......................................................................................................................................................25 Phoenix Maintenance District....................................................................................................................................27 Prescott District .......................................................................................................................................................28 Safford District .........................................................................................................................................................32 Tucson District.........................................................................................................................................................35 Yuma District ...........................................................................................................................................................38 Statewide Priority Shoulder Improvement Locations ..................................................................................................40 Shoulder Improvements on Multilane Highways .....................................................................................................41 i List of Tables 1. Prioritization Criteria for Shoulder Improvements on Two-Lane Highways ..............................................................4 2. Prioritization Criteria for Shoulder Improvements on Multilane Highways................................................................6 3. Two-Lane Highways - Candidate Shoulder Improvement Locations in Flagstaff District ..........................................9 4. Two-Lane Highways - Ranking of Priority Candidate Locations in Flagstaff District ..............................................12 5. Two-Lane Highways - Candidate Shoulder Improvement Locations in Globe District ............................................14 6. Two-Lane Highways - Ranking of Priority Candidate Locations in Globe District ..................................................18 7. Two-Lane Highways - Candidate Shoulder Improvement Locations in Holbrook District .......................................20 8. Two-Lane Highways - Ranking of Priority Candidate Locations in Holbrook District .............................................23 9. Two-Lane Highways - Candidate Shoulder Improvement Locations in Kingman District .......................................25 10. Two-Lane Highways - Ranking of Priority Candidate Locations in Kingman District..............................................26 11. Two-Lane Highways - Candidate Shoulder Improvement Locations in Phoenix Maintenance District ....................27 12. Two-Lane Highways - Ranking of Priority Candidate Locations in Phoenix Maintenance District ...........................27 13. Two-Lane Highways - Candidate Shoulder Improvement Locations in Prescott District ........................................28 14. Two-Lane Highways - Ranking of Priority Candidate Locations in Prescott District ..............................................30 15. Two-Lane Highways - Candidate Shoulder Improvement Locations in Safford District..........................................32 16. Two-Lane Highways - Ranking of Priority Candidate Locations in Safford District ................................................34 17. Two-Lane Highways - Candidate Shoulder Improvement Locations in Tucson District .........................................35 18. Two-Lane Highways - Ranking of Priority Candidate Locations in Tucson District ................................................37 19. Two-Lane Highways - Candidate Shoulder Improvement Locations in Yuma District ............................................38 20. Two-Lane Highways - Ranking of Priority Candidate Locations in Yuma District ..................................................39 21. Multilane Highways - Statewide Ranking of Priority Candidate Locations .............................................................41 List of Figures 1. Identification Process for Shoulder Improvements on Two-Lane Highways ............................................................5 2. Identification Process for Shoulder Improvements on Multilane Highways .............................................................7 3. Two-Lane Highways - Statewide Priority Candidate Locations .............................................................................40 4. Multilane Highways - Statewide Priority Candidate Locations ..............................................................................42 ii Study Overview Located adjacent to a roadway's travel lanes, highway shoulders are essential components on any road section. Highway shoulders serve several purposes:  Creates a safe zone for vehicles to safely exit travel lanes during emergency situations  Allows motorists an area to maneuver if they exit the travel lane  Increases sight distance of horizontal curves  Provides bicyclists with a safe area adjacent to vehicle travel lanes  Increases driver's sense of safety  Provides structural support to highway pavement  Protects the highway surface from damage caused by water flow  Creates a storage area during snow removal Shoulder improvements can lead to a plethora of safety and operational improvements, such as reduction in crashes, safe pedestrian and bicycle facilities, mitigation of drainage issues, and increased roadway capacity. Potential safety hazards can occur when a vehicle leaves the travel way and there is a significant material and elevation difference between highway pavement and shoulder surfaces. This elevation difference can affect vehicle stability, reduce a driver’s ability to handle the vehicle, and often cause head-on, sideswipe, rollover, and fixed object crashes. Shoulder paving is recognized as a positive countermeasure to reduce a shoulder drop-off hazard that will accommodate stopped vehicles to avoid encroachment from the travel way, facilitate maintenance work, provide access for emergency vehicles, and protect pavement structural integrity. A paved shoulder can also assist in preventing damage to the road structure caused by water infiltration and can provide motorists with a warning system when veering off the roadway (i.e., rumble strips). Purpose and Need With the ultimate purpose of enhancing safety and improving mobility, the Statewide Shoulders Study was initiated to develop a prioritized list of candidate locations for shoulder improvements. The need for this study stems directly from ADOT’s desire to increase safety and mobility along the Arizona State Highway System. The project purpose is demonstrated with the following statement of need:  Create Methodology. As the first statewide, shoulder improvement prioritization project conducted in Arizona, a methodology needs to be developed that utilizes available data to accurately identify deficiencies. A statewide and district-level prioritization is needed in order to appropriate limited funds for priority projects.  Develop List of Shoulder Improvement Locations. Currently, there is no statewide or ADOT Engineering District-wide listing of prioritized locations for shoulder improvement projects. This document will serve as 1 guidance for determining priority roadway segments within each ADOT District and throughout the State that require funding.  Develop Feasible, Cost Effective Implementation Plan. High priority projects need to be evaluated for feasibility and cost-effectiveness. Due to limited funding, innovative and cost effective alternatives beyond traditional pavement applications need to be explored. Technical Advisory Committee This study was guided by a Technical Advisory Committee (TAC). The role of the TAC was to provide technical guidance, support, advice, suggestions, recommendations, and to perform document reviews throughout the study process. TAC members included representatives from:  ADOT Multimodal Planning Division  ADOT Globe Engineering District  ADOT Phoenix Engineering District  ADOT Safford Engineering District  ADOT Tucson Engineering District  ADOT Roadway Engineering Group  ADOT Prescott Engineering District  ADOT Maintenance Group  ADOT Yuma Engineering District  ADOT Bridge Group  ADOT Flagstaff Engineering District  ADOT Right of Way  ADOT Holbrook Engineering District  ADOT Traffic Safety Section  ADOT Kingman Engineering District  Federal Highway Administration (FHWA) 2 Stakeholder Outreach The first phase of stakeholder outreach included individual meetings with each ADOT District staff. Meetings with the Districts were conducted April 22 - April 30, 2014. The primary purpose of these meetings was to obtain feedback from each of the Districts about the following:       Review and verify existing shoulder width conditions Review general and shoulder related crash data analysis results Identify any inconsistencies or errors in the background data Obtain Districts preference for preliminary project locations based on their understanding of local conditions Identify already planned and programmed improvements, if any Obtain consensus on evaluation criteria and preliminary prioritization methodology The second phase of stakeholder outreach was conducted October 8 – 15, 2014 and involved individual meetings with ADOT District staff. The primary purpose of these meetings was to review:      Design guidelines used to define deficiencies Listing of preliminary candidate locations District suggested locations Crash data analysis results Recommended ranking/prioritization criteria The study team presented the design guidelines used to define shoulder deficiencies. ADOT’s Roadway Design Guidelines were used as the primary criteria to identify shoulder deficiencies. Highway Safety Manual (HSM) indicated that widening the shoulder from 6 – 8 ft may not yield a significant reduction in crashes; the study team recommended that roadway segments that had at least 6 ft of shoulder width be eliminated from consideration for two-lane highways. District staff concurred with the recommendation and asked the study team to confirm that shoulder related crashes were not a concern before eliminating those segments from consideration. District staff also concurred with the study team’s suggestion to remove segments that have 8 – 10 ft shoulder on multilane highways unless crash analysis warrants the need for shoulder improvements. A full listing of comments received during the stakeholder outreach meetings is included in the Working Paper 1: Existing Conditions and Working Paper 2: Evaluation Criteria and Plan for Improvements. 3 Identification and Prioritization Methodology Two-lane highways and multilane highways have different physical and traffic characteristics and their mobility and safety performance is evaluated using different parameters. For this reason, separate methodologies were developed to identify and prioritize:   Shoulder improvements on two-lane highways Shoulder improvements on multilane highways Methodology to Identify Shoulder Improvements on Two-Lane Highways Figure 1 illustrates the steps utilized to identify and prioritize potential locations for shoulder improvements on two-lane highways. Once preliminary lists of potential candidates were identified, they were ranked on a statewide basis using the criteria and score ranges listed in Table 1. Table 1: Prioritization Criteria for Shoulder Improvements on Two-Lane Highways Criteria Mobility – 25% Existing LOS: PTSF – Percent Time Spent Following Existing LOS: PFFS – Percent of Free Flow Speed Future LOS: PTSF – Percent Time Spent Following Future LOS: PFFS – Percent of Free Flow Speed Wide load corridor Safety – 50% Existing Crash Rate Existing Crash Severity (EPDO) Future Crash Severity (Potential Future Crash Benefit) Bicycle/Pedestrian Usage Level Max Points 25 5 5 5 5 5 50 15 15 10 10 Construction Feasibility - 25% Cost Per Lane Mile 25 10 Potential Number of Bridges that Require Widening 15 Points Distribution Z-score method* Z-score method* Z-score method* Z-score method* 5 points if segment was a wide load corridor; 0 points if NOT a wide load corridor Z-score method* Z-score method* Z-score method* 10 points for segments with high bike/ped usage; 0 points if NOT a bike/ped corridor Proportional distribution of points based on cost per lane mile 0 bridges = 15 pts; 1 bridge = 12 pts; 2 bridges = 10 pts; 3 bridges = 8 pts; 4 bridges = 6 pts; 5 bridges = 4 pts; 6 bridges = 2 pts; Greater than 6 bridges = 0 pts *Each record’s z-score was determined based on its relative distance from the mean of all records. Based on the record’s z-score, a proportional point value between 0 and Max Points was then assigned to each record. 4 Figure 1: Identification Process for Shoulder Improvements on Two-Lane Highways 5 Methodology to Identify Shoulder Improvements on Multilane Highways Figure 2 illustrates the steps utilized to identify and prioritize potential locations for shoulder improvements on multilane highways. Once preliminary lists of potential candidates were identified, they were ranked on a statewide basis using the criteria and score ranges listed in Table 2. Table 2: Prioritization Criteria for Shoulder Improvements on Multilane Highways Criteria Mobility – 25% Existing LOS: Density Future LOS: Density Wide Load Corridor Safety – 50% Existing Crash Rate Existing Crash Severity (EPDO) Potential Future Crash Reduction Level – Right Shoulder Potential Future Crash Reduction Level – Left Shoulder Bicycle/Pedestrian Usage Level Construction Feasibility 25% Max Points 25 10 10 5 50 15 15 12 3 5 Points Distribution Z-score method* Z-score method* 5 points if segment was a wide load corridor; 0 points if NOT a wide load corridor Z-score method* Z-score method* Z-score method* Z-score method* 10 points for segments with high bike/ped usage; 0 points if NOT a bike/ped corridor 25 Cost Per Lane Mile 10 Potential Number of Bridges that Require Widening 15 Proportional distribution of points based on cost per lane mile 0 bridges = 15 pts; 1 bridge = 12 pts; 2 bridges = 10 pts; 3 bridges = 8 pts; 4 bridges = 6 pts; 5 bridges = 4 pts; 6 bridges = 2 pts; Greater than 6 bridges = 0 pts * Each record’s z-score was determined based on its relative distance from the mean of all records. Based on the record’s z-score, a proportional point value between 0 and Max Points was then assigned to each record. 6 Figure 2: Identification Process for Shoulder Improvements on Multilane Highways 7 Shoulder Improvements on Two-Lane Highways For two-lane highways, a shoulder deficiency analysis was conducted to identify all highway segments that did not meet minimum shoulder width standards. These segments were then evaluated against the following criteria to identify comprehensive candidate locations for shoulder improvements.  LOS C or worse  Crash rate is greater than “average statewide highway crash rate plus one standard deviation” A review of the comprehensive candidate locations revealed that several segments were too long and may not be feasible for implementation. To help the Districts further prioritize the segments, each larger segment was divided into smaller segments. These smaller segments were evaluated against the following additional set of criteria to generate a list of priority candidate locations that would be easier to implement.  Existing and future (2030) LOS  Crash rate, number of crashes, crash severity  Predicted future crash benefit of shoulder improvement  Wide load corridor – yes/no  Bicycle/pedestrian usage level – high/medium/low  Planning level costs & construction feasibility Example: The priority candidate locations were scored and ranked at both Statewide and District level and grouped into three tiers – high, medium, and low priority. The results for each District are summarized in the following sections:  Comprehensive candidate locations that need shoulder improvements  Priority segments for shoulder improvements. Locations identified for shoulder improvements in Tables 3 - 11 represent only the general problem area and not the exact location and length of the shoulder improvements. 8 Planning Level Cost Estimates Planning level cost estimates were developed based on typical per-mile/foot construction costs for widening and are expressed in 2015 dollars and have not been field verified. The following assumptions were used to derive the planning level cost estimates for the Tier 1 (priority) candidate segments:  Widening shoulder to 8 FT: $900,000/mile for flat terrain o For each segment, the actual footage of additional shoulder width needed was estimated and the cost was then prorated. For example, if the candidate segment currently has a 2 FT shoulder, the prorated cost to widen the shoulder an additional 6 FT to meet the 8 FT standard was estimated. o Existing actual shoulder widths varied within each candidate segment; therefore, segments were divided into 0-2 FT, 3-5 FT, 5-8 FT, and 8 FT or greater shoulder widths. The midpoint of the candidate segments shoulder width range was utilized as the basis for calculating cost estimates. For example, an average shoulder width of 1 FT was utilized for candidate segments with a shoulder width range between 0-2 FT, 4 FT for segments with a 3-5 FT range, and so forth.  Topographical constraints: o Segments with rolling terrain – an additional 10% was added to the base widening cost o Segments with mountainous terrain: an additional 20% was added to the base widening cost  Bridge Widening: $200/SQFT o The number of bridges within each candidate segment was obtained from the National Bridge Inventory database. Each bridge’s overall length, width, and deck width was also obtained. o For each bridge, the additional square footage needed to widen the bridge was determined. o The cost to widen each bridge was then estimated.  Costs associated with acquiring right-of-way, widening culverts, and environmental mitigation are not included in estimates.  Unless otherwise noted, recommended projects are not yet funded. Due to topographical or other physical constraints adjustment factors may need to be applied to the cost estimates to account for increased construction costs. During project implementation the costs for each project may vary; therefore, during the design phase a detailed analysis should be performed to determine actual costs. 9 Flagstaff District Table 3 presents the list of candidate locations for shoulder improvements on two-lane highways in the Flagstaff District. The candidate locations are ranked at the statewide and district level and grouped into three tiers – high, medium, and low priority. Table 4 summarizes the priority candidate improvement locations by tier. Table 3: Two-Lane Highways - Candidate Shoulder Improvement Locations in Flagstaff District Route Dir BMP EMP Flagstaff District S 064 Both S 064 Both 185.6 187.9 187.2 194.0 S 064 Both 196.0 233.6 S 064 S 064 S 064 S 067 S 098 Westbound Both Both Both Both 234.3 236.0 281.7 579.0 294.0 235.3 237.0 289.5 610.0 361.0 Priority Segments: (Segments that exceed LOS and Crash Rate Threshold)* MP185.6 - MP187.2 MP187.9 - MP190 MP190 - MP192 MP192 - MP194 MP196 - MP198 MP198 - MP200 MP200 - MP202 MP202 - MP204 MP204 - MP206 MP210 - MP212 MP212 - MP214 MP214 - MP216 MP216 - MP218 MP218 - MP220 MP220 - MP222 MP222 - MP224 MP224 - MP226 MP226 - MP228 MP228 - MP230 MP230 - MP232 MP234.3 - MP235.3 MP267 - MP268 MP284 - MP286 MP298 - MP300 MP300 - MP302 MP302 - MP304 MP308 - MP310 MP318 - MP320 MP328 - MP330 10 Table 3: Two-Lane Highways - Candidate Shoulder Improvement Locations in Flagstaff District (Continued) Route Dir BMP EMP Priority Segments: (Segments that exceed LOS and Crash Rate Threshold)* Flagstaff District S 179 Both 299.0 304.5 S 389 SA089 Both Both 0.0 374.0 32.1 389.8 SA089 U 089 U 089 U 089 U 089 U 089 U 089 U 089 U 089 U 089 U 089 Both Both Both Both Both Both Both Both Both Both Both 390.4 456.6 469.6 471.6 474.5 477.4 493.1 505.7 509.2 519.9 524.4 398.7 461.8 470.8 472.3 475.4 478.3 494.1 507.1 512.2 521.2 556.8 U 160 Both 311.0 324.0 U 160 Eastbound 324.0 332.0 MP330 - MP332 MP342 - MP344 MP344 - MP346 MP348 - MP350 MP350 - MP352 MP352 - MP354 MP354 - MP356 MP299 - MP302 MP302 - MP304.5 MP374 - MP376 MP380 - MP382 MP384 - MP386 MP386 - MP389.8 MP461.8 - MP460.7 MP469.6 - MP470.8 MP471.6 - MP472.3 MP474.5 - MP475.4 MP477.4 - MP478.3 MP493.1 - MP494.1 MP505.7 - MP507.1 MP509.2 - MP512.2 MP519.9 - MP521.2 MP548 - MP550 MP550 - MP552 MP552 - MP554 MP554 - MP556.8 MP311 - MP314 MP314 - MP316 MP316 - MP318 MP318 - MP320 11 Table 3: Two-Lane Highways - Candidate Shoulder Improvement Locations in Flagstaff District (Continued) Route Dir BMP EMP Flagstaff District U 160 Both 332.0 356.0 U 160 U 160 Eastbound Both 356.0 358.0 358.0 362.0 U 180 Both 218.0 237.4 Priority Segments: (Segments that exceed LOS and Crash Rate Threshold)* MP336 - MP338 MP340 - MP342 MP342 - MP344 MP344 - MP346 MP346 - MP348 MP350 - MP352 MP352 - MP354 MP354 - MP356 MP356 - MP358 MP358 - MP360 MP360 - MP362 MP218 - MP220 MP220 - MP223.2 MP223.2 - MP226 U 180 Both 239.4 244.2 U 180 Both 245.4 264.0 U 180 Eastbound 264.0 265.6 UA089 Both 524.0 537.3 UA089 Both 538.5 546.0 UA089 Southbound 546.0 548.0 UA089 Both 548.0 609.0 MP590 - MP592 UA089 Both 610.2 612.3 Priority segments represent segments that - Have LOS worse than C - Crash rate greater than “average statewide highway crash rate plus one standard deviation” District Rankings are Provided in the Following Table 12