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HomeMy WebLinkAboutMONTAVA - PHASE G & IRRIGATION POND - BDR210013 - SUBMITTAL DOCUMENTS - ROUND 6 - TRANSPORTATION ISSUEkimley-horn.com 11400 Commerce Park Drive, Suite 400, Reston, VA 20191 972.776.1749 September 27, 2023 Max Moss, President HF2M Colorado 430 N College Ave. Suite 410 Fort Collins, CO 80524 Re:Montava – N Timberline Road Kidney Bean Intersection Safety Considerations INTRODUCTION The Montava design team met via virtual meeting with the City of Fort Collins on Tuesday, September 5, 2023, to discuss potential intersection control modifications for Timberline Road at Chesapeake Drive and Timberline Road at Longwood Drive if a future high crash frequency results from the installation of the proposed kidney bean intersections. Several action items resulted from the meeting, consisting of: 1. The Montava team will update the kidney bean intersection control options comparison exhibit to reflect proposed pavement markings associated with each alternative (attached Exhibit 01). 2. The Montava team will base the understanding of acceptable crash results by using a comparison of appropriate crash prediction methodology (FHWA’s Safety Performance for Intersection Control Evaluation – SPICE). 3. The Montava team will prepare a written understanding of acceptable intersection control safety performance as it relates to reported crashes at the kidney bean intersections that can be agreed upon by the City of Fort Collins. KIDNEY BEAN INTERSECTION CONTROL OPTIONS COMPARISON An updated exhibit (Exhibit 01) is attached to this memo that shows the potential changes to the proposed kidney bean intersections that could be provided if a crash frequency exceeds the agreed upon threshold at the subject intersections. The three alternative intersection control types shown on Exhibit 01 would require limited modifications of the kidney bean intersection and would continue to utilize the raised crosswalks on all four legs of the intersection. SAFETY PERFORMANCE FOR INTESECTION CONTROL EVALUATION (SPICE) The results from FHWA’s SPICE tool are attached to this memo as Exhibit 02. A safety prediction analysis was conducted for a traffic signal, two-way stop control and roundabout scenarios within the SPICE spreadsheet. Since kidney bean intersections consist of varying geometry and are not common to the U.S., a safety prediction model is not available at this time to determine anticipated crashes based on this type of intersection control method. The traffic signal alternative control method has been left off of Exhibit 01 since the two subject intersections do not appear to meet traffic signal warrants for the duration of the study period (to year 2045). Based on the low traffic volume anticipated at the subject intersections through the design year, a crash frequency of less than one (1) crash per year is anticipated for all the studied intersection control types. Total actual crashes at a given intersection may exceed predicted values based on varying contributing factors. Therefore, some leniency should be given in establishing acceptable crash frequency thresholds DR A F T kimley-horn.com 11400 Commerce Park Drive, Suite 400, Reston, VA 20191 972.776.1749 for the proposed kidney bean intersections before an intersection control modification is implemented. The severity of the crash(es) should also be weighed in determining a threshold. Fatal crashes are uncommon and are typically not prone to repetition at a given intersection. Fatal crashes tend to occur when an operator of a motor vehicle has made a significant driving error, has far-exceeded the posted speed limit, and/or has undergone a medical condition. Repeat injury-type crashes can be an indicator that a contributing factor at the subject intersection may be able to be addressed to remediate a high frequency of injury crashes from occurring in the future. An engineering study should be conducted to evaluate the crash data to determine if contributing factors exist that may be mitigated through an alternative treatment or modification of the existing intersection. WRITTEN UNDERSTANDING OF ACCEPTABLE INTERSECTION CONTROL SAFETY PERFORMANCE The following language is drafted by the Montava team for City of Fort Collins review and comments for a future agreed upon understanding of the resulting crash frequency at any proposed kidney bean intersection within the Montava development. Whereas the Montava design team proposes to install what is defined to be “kidney bean intersections”, the following thresholds of resulting crashes at a kidney bean intersection constructed in the Montava development will require the engineering study and recommendation to modify a kidney bean intersection to an alternative form of intersection control, upon the City of Fort Collins review and approval of the engineering study, and City of Fort Collins written agreement to modify the subject intersection, shall documented crash frequency meet or exceed the following parameters. ·If more than five (5) reported non-injury intersection-related crashes occur within a 12-month period. Crashes include vehicle-to-vehicle, vehicle-to-pedestrian, and vehicle-to-bicycle. ·If two (2) or more reported injury or fatal intersection-related crashes occur in a 12-month period. Crashes include vehicle-to-vehicle, vehicle-to-pedestrian, and vehicle-to-bicycle. If either of the above thresholds are met, an engineering study will be performed by the Montava team using the then-current version of the Colorado DOT Intersection Control Assessment Tool (ICAT). In conjunction with the ICAT analysis, up-to-date traffic data collection at the subject intersection will be provided by the Montava team to be used in the ICAT analysis. The engineering study prepared by the Montava team, including the ICAT analysis, will be provided to the City of Fort Collins for review and consideration of the Montava team’s recommended replacement intersection control type. The preparation of an engineering study by the Montava team will be prepared if the crash frequency noted above at the kidney bean intersections is met or exceeded within a five-year period starting on the date of the City’s initial written acceptance of the construction of the Montava roadway infrastructure along N Timberline Road. Based on our professional opinion, five years is a long enough duration for traffic to normalize and to document crash statistics and identify potential issues related to the intersection geometry, control type, and/or control features that indicate a recommended modification to the intersection. Attachments: · Exhibit 01 – Intersection Comparisons Exhibit · Exhibit 02 - Safety Performance for Intersection Control Evaluation (SPICE tool) DR A F T Exhibit 01 - Kidney Bean Intersection Alternatives Comparison September 2023 Note: This exhibit is meant to convey the potential changes of intersection control methodology from the base condition of the kidney bean intersection (far left). The line work above may not reflect exact geometric conditions of the current kidney bean intersection design as ongoing minor changes are made for vehicle accommodation and grading. Refer to the construction drawings prepared by Martin|Martin for up-to-date geometrics. KIDNEY BEAN INTERSECTION -CURRENT PROPOSED DESIGN -SIDE STREET YIELD CONTROL - CIRCULATING YIELD CONTROL ACROSS THE NORTHBOUND AND SOUTHBOUND ENTRIES CONVERSION TO TWO-WAY STOP CONTROL -SIDE STREET STOP CONTROL - SIDE STREET YIELD CONTROL - CIRCULATING STOP CONTROL ACROSS THE NORTHBOUND AND SOUTHBOUND ENTRIES CONVERSION TO TWO-WAY STOP CONTROL (CONVENTIONAL INTERSECTION) -MINOR MEDIAN TREATMENTS TO THE NORTHERN AND SOUTHERN MEDIANS. -REMOVAL OF THE CENTER ISLAND CONVERSION TO MINI-ROUNDABOUT - MINOR MEDIAN TREATMENTS TO THE NORTHERN AND SOUTHERN MEDIANS. -MODIFICATION OF THE CENTER ISLAND. DR A F T Safety Performance for Intersection Control Evaluation Project Information Project Name: Intersection: Agency: Use this button to clear all inputs/outputs and reset the tool to its initial defaults Montava Timberline Road at Chesapeake (and at Longwood) City of Fort Collins, CO Fort Collins Colorado 9/13/2023 J.L. VonAhsen Project Reference: City: State: Date: Analyst: Reset SPICE ToolLoad Cap-X Exhibit 02 DR A F T At-Grade Intersections (Select from Dropdown) Opening and Design Year (Select from Dropdown) 2027 2045 On Urban and Suburban Arterial (Select from Dropdown) Urban (Select from Dropdown) 4-leg (Select from Dropdown) 4,500 1,350 4,500 800 Control Strategy Base Intersection Traffic Signal -- Traffic Signal (Alternative Configuration)-- Minor Road Stop -- All-Way Stop (No SPF/CMF Available)-- 1-Lane Roundabout Minor Road Stop 2-Lane Roundabout Minor Road Stop Displaced Left-Turn (DLT)Traffic Signal Median U-Turn (MUT)Traffic Signal Signalized Restricted Crossing U-Turn (RCUT)Traffic Signal Unsignalized Restricted Crossing U-Turn (RCUT)Minor Road Stop Continuous Green-T (CGT) Intersection Traffic Signal Jughandle Traffic Signal Other 1 Traffic Signal Other 2 Minor Road Stop No No No No No No No Design Year – Major Road AADT Design Year – Minor Road AADT Opening Year – Major Road AADT Opening Year – Minor Road AADT Number of Legs Safety Performance for Intersection Control Evaluation Control Strategy Selection Intersection Type Opening Year Design Year Analysis Year Facility Secondary Type (For Roundabouts Only) Facility Type If the input AADT exceeds the range of the data used to develop one or more of the SPFs, the resulting predictions should be used with caution. Note:The CMFs associated with roundabouts differentiate between urban and suburban areas, while the SPFs and CMFs for all other intersections do not. Include Yes Yes No Yes No No No Exhibit 02 DR A F T Number of Approaches with Left-Turn Lanes Number of Approaches with Right-Turn Lanes Number of Uncontrolled Approaches with Left-Turn Lanes Number of Uncontrolled Approaches with Right-Turn Lanes Skew Angle Lighting Present # of Approaches Permissive LT Signal Phasing # of Approaches Permissive/Protected LT Signal Phasing # of Approaches Protected LT Signal Phasing Number of Approaches with Right-Turn-on-Red Prohibited Red Light Cameras Present Pedestrian Volume by Activity Level User-Specified Sum of all daily pedestrian crossing volumes Max # of Lanes Crossed by Pedestrians Number of Bus Stops within 1000 ft of Intersection Schools within 1000 ft of intersection Number of Alcohol Sales Establishments within 1000 ft of Intersection All yellow cells will be automatically populated by a macro. If users want to do a planning-level analysis, they can leave the automatic inputs as-is 2 0 Med Low (240) No Yes N/A 0 2 No Do not include stop controlled approaches for minor stop 1-lane Roundabout 0 2 Traffic Signal 0 0 Input Minor Road Stop N/A N/A 0 N/A Additional Required Control Strategy Inputs N/A 2 0 0 CMF - No Inputs Required Highway Safety Manual Part C CMF Inputs 2 No 3 240 Control Strategy Safety Performance for Intersection Control Evaluation At-Grade Intersection Inputs Keep default values below here for planning-level analysis, override with actual values for full HSM Analysis. N/A Yes A yellow cell indicates the value may be used in the SPF computation Exhibit 02 DR A F T Project Name:Intersection Type Intersection:Opening Year Agency:Design Year Project Reference:Facility Type City:Number of Legs State:1-Way/2-Way Date:# of Major Street Lanes Analyst:Major Street Approach Speed Control Strategy Crash Type Opening Year Design Year Total Project Life Cycle Total 0.58 0.52 10.46 Fatal & Injury 0.08 0.07 1.35 Total 0.95 0.85 17.15 Fatal & Injury 0.34 0.30 6.13 Total 0.65 0.57 11.61 Fatal & Injury 0.24 0.21 4.30 AADT Within Prediction Range? N/A Yes Less than 55 mph 5 or fewer Minor Road Stop Traffic Signal 9/13/2023 1-lane Roundabout Safety Performance for Intersection Control Evaluation Tool Yes Crash Prediction Summary Results Summary of crash prediction results for each alternative At-Grade Intersections 2027 J.L. VonAhsen Montava 2045 Project Information On Urban and Suburban Arterial 4-leg 2-way Intersecting 2-way Timberline Road at Chesapeake (and at Longwood) City of Fort Collins, CO Fort Collins Colorado Exhibit 02 DR A F T A traffic signal crash prediction is provided, however, based on the anticipated low volume of the subject intersec- tions a traffic signal does not appear to be warranted at Chesapeake or at Longwood along N Timberline Road. A traffic signal has been included in the SPICE analysis simply for comparative reasons only.