Roundabout Feasibility Memorandum

Transcription

1 Roundabout Feasibility Memorandum To From Gwen Pipkin Bill Howell Date June 18, 2013 Subject Roundabout Feasibility Study SR 29 PD&E Study From Oil Well Road to SR 82 Collier County, FL FPID The Florida Department of Transportation is conducting a Project Development and Environment (PD&E) study to evaluate potential transportation improvements to SR 29 from Oil Well Road to SR 82 in Collier County, FL. As part of this PD&E study, roundabouts are being considered at the 12 locations shown in Exhibit 1. This memorandum documents the feasibility of each of these roundabouts. All 12 multi-lane roundabouts were screened using a multistep process described as follows: Initially, each intersection was analyzed as a roundabout in the 2040 design year. When the roundabout was found to operate favorably, the intersection was then analyzed in the design year under a signalized condition. When the roundabout was found to provide operations equal to or better than the signalized intersection, the roundabout was then evaluated in the existing year to determine if the roundabout could be constructed initially as a single lane roundabout and later expanded to two lanes. After conducting operational analyses of the design and existing years, a safety analysis was performed. The purpose of this safety analysis was to determine the potential safety benefit associated with implementing a roundabout. This analysis was based on the five most recent years of crash data available. Conceptual designs were prepared for all roundabouts that were viewed as feasible, based on the traffic analysis. These designs were used to quantify the amounts of right of way and wetland impacts associated with both roundabouts and signal controlled intersections. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 1

2 Exhibit 1 SR 29 Alternatives and Potential Roundabout Locations H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 2

3 Location A: SR 29 at CR 846 (Existing Alternative) This intersection is located on the eastern edge of Immokalee. CR 846, a two lane roadway, provides access to the Immokalee Regional Airport. The 2040 volumes and lane configurations of the intersection are provided in Exhibit 2. The 2040 traffic volumes were obtained from the SR 29 Project Traffic Technical Memorandum, completed in September Exhibit Volumes and Lane Configuration for Location A 2040 Intersection Volumes Signalized Dual Lane Roundabout Future Operational Screening Based on HCM analysis, a roundabout will operate at LOS F under 2040 conditions (Attachment A). Based on current LOS standards, this intersection should operate at LOS C or better. Due to the failing operations of this roundabout, no signalized analysis of the intersection was performed. Initial Operational Screening No existing year evaluation was conducted as the roundabout fails under 2040 conditions. Initial Safety Screening No crash data was obtained for this location. Geometric Screening No conceptual designs for a roundabout at this location were prepared. Conclusions The southbound volumes of this intersection are too large to be accommodated by a two lane roundabout. Based on this finding, no additional traffic analysis or screening is necessary. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 3

4 Location B: SR 29 at New Market Road (Existing Alternative) The intersection of SR 29 and New Market Road is located 700 feet northwest of Location A. The 2040 volumes and lane configurations of each intersection type are provided in Exhibit 3. The 2040 traffic volumes were obtained from the SR 29 Project Traffic Technical Memorandum. Exhibit Volumes and Lane Configuration for Location B 2040 Intersection Volumes Signalized Dual Lane Roundabout Future Operational Screening The HCM results for Location B indicate a roundabout will operate at LOS F under 2040 conditions. These results were believed to be influenced by the significant turning volumes to and from New Market Road. To confirm the results, this roundabout was analyzed in VISSIM, which yielded 2040 operating conditions of LOS C or better (Attachment A). For comparison purposes, a signalized intersection at Location B is expected to operate at LOS C or better under 2040 conditions. Initial Operational Screening No analyses of the existing conditions have been prepared. Initial Safety Screening Safety data for this location was not obtained. Geometric Screening No conceptual designs for a roundabout at this location have been prepared. Conclusions Based on earlier findings, Location A should be signalized. Intersection control types should be consistent between Locations A and B, due to their close proximity to each other. For this reason, no additional traffic analysis or screening is necessary for Location B. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 4

5 Location C: SR 29 at 1 st Street (Existing Alternative) The intersection of SR 29 and 1 st Street is located at the eastern edge of downtown. SR 29 and the southern leg 1 st Street are four lane roadways. The northern leg of 1 st Street is a two lane roadway. The 2040 volumes and lane configurations of each intersection type are provided in Exhibit 4. The 2040 traffic volumes were obtained from the SR 29 Project Traffic Technical Memorandum. Exhibit Volumes and Lane Configuration for Location C 2040 Intersection Volumes Signalized Dual Lane Roundabout Future Operational Screening A roundabout at Location C will operate at LOS F under 2040 conditions, based on HCM methodologies (Attachment A). The analysis of this intersection was continued beyond the HCM screening due to an identified need for traffic calming at this location. This need could be met through implementing a roundabout at Location C. Based on this need, the roundabout of Location C was further analyzed using VISSIM. The VISSIM results confirmed this roundabout will operate at LOS F under 2040 conditions; however, the VISSIM results indicate intersection delay values that are significantly less than those of the HCM analyses (Attachment A). Despite this reduction in delays, the roundabout cannot accommodate the significant turning volumes of the intersection at the desired LOS. Initial Operational Screening Location C was not evaluated under existing conditions as a roundabout failed to produce acceptable operating conditions in the design year. Initial Safety Screening No safety analysis was performed for Location C. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 5

6 Geometric Screening No conceptual designs were prepared for a roundabout at Location C. Conclusions A roundabout at Location C will operate at LOS F under 2040 peak hour conditions. Due to this finding, no further screening was conducted at Location C. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 6

7 Location D: SR 29 at 9 th Street (Existing Alternative) The intersection of SR 29 and 9 th Street is located at the western edge of downtown Immokalee. The 2040 volumes and lane configurations of each intersection type are provided in Exhibit 5. Exhibit Volumes and Lane Configuration for Location D 2040 Intersection Volumes Signalized Dual Lane Roundabout Future Operational Screening The HCM results for Location D indicate a roundabout will operate at LOS F under 2040 conditions (Attachment A). Due to the differences between the HCM and VISSIM results of Location C, Location D was also evaluated using VISSIM. The VISSIM results indicate a roundabout will operate at LOS C (AM) and LOS F (PM) under 2040 conditions. The intersection at Location D should operate at LOS D or better, based on current LOS standards. Initial Operational Screening Location D was not evaluated under existing conditions. Initial Safety Screening No safety analysis was performed for Location D. Geometric Screening No conceptual designs were prepared for a roundabout at Location D. Conclusions A roundabout at Location D will operate at LOS F under 2040 PM peak hour conditions. Due to this finding, no further screening was conducted at Location D. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 7

8 Location E: SR 29 at SR 82 (Existing Alternative) Both SR 29 and SR 82 are four lane roadways, intersecting north of Immokalee. The roundabout option consists of a dual lane roundabout with splitter islands, a center island with a truck apron and exclusive eastbound right turn lanes that allow users to bypass the roundabout. The 2040 traffic volumes and lane configurations of Location E are provided in Exhibit 6. The 2040 traffic volumes were obtained from the SR 29 Project Traffic Technical Memorandum, completed in September Exhibit Volumes and Lane Configuration for Location E 2040 Intersection Volumes Signalized Dual Lane Roundabout Future Operational Screening The HCM analyses of a roundabout controlled intersection, the roundabout would operate at LOS E (AM) and LOS F (PM) in the peak hours of 2040 (Attachment A). Based on current LOS criteria, this intersection should operate at LOS C or better. Due to the complex lane configuration of the roundabout at this intersection, the roundabout analyses were also conducted using VISSIM version The VISSIM results (Attachment A) indicate the roundabout would operate at LOS A in both peak hours under 2040 conditions. The discrepancy in results between HCM and VISSIM are believed to be attributed to the complex lane configuration and the significant volume of turning traffic. Since the VISSIM results for this intersection indicated operating conditions better than the LOS C standard, the intersection was also analyzed as a signalized intersection for comparison purposes. The HCM results indicate a signalized intersection at this location would operate at LOS D in both the AM and PM peak hours of 2040 (Attachment A). This signalized intersection would fail to provide operating conditions expected of this intersection. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 8

9 Initial Operational Screening The existing intersection is unsignalized, with SR 82 (west leg) being stop controlled (Exhibit 7). Exhibit 7 Existing Volumes and Lane Configuration for Location E 2011 Intersection Volumes Unsignalized Under existing 2011 conditions, two movements do not meet the LOS C criteria that is applicable to this intersection. The eastbound right turn movement operates at LOS D under the AM peak hours. In the PM peak hours, the eastbound left turn movement operates at LOS F (Table 1). Table Peak Hour Operating Conditions for Location E (stop controlled) Peak Hour Approach Movement HCM Intersection Summary Delay (sec/veh) LOS AM EB Left 17.9 C Right 28.5 D NB Left 8.6 A PM EB Left F Right 12.6 B NB Left 10.5 B Both single and dual lane roundabouts were analyzed for this intersection. The lane configurations of both roundabouts are provided in Exhibit 8. Based on HCM analysis of these roundabout configurations, a single lane roundabout would operate at LOS C and LOS D in the peak hours under existing conditions (Table 2). A dual lane roundabout would operate at LOS A in both peak hours under H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 9

10 2011 conditions. Based on current LOS standards, this intersection should not be initially constructed as a single lane roundabout and later expanded to a dual lane roundabout. Exhibit 8 Potential Roundabout Configurations for Location E Single Lane Roundabout Dual Lane Roundabout Table Peak Hour Operating Conditions for Location E (Roundabouts) HCM Intersection Summary Peak Hour Approach Single Lane Roundabout Delay (sec/veh) LOS Dual Lane Roundabout Delay (sec/veh) LOS EB 26.3 D 8.5 A AM NB 7.9 A 5.7 A SB 8.9 A 6.1 A Intersection Total 18.3 C 7.3 A EB 11.6 B 6.6 A PM NB 34.9 D 9.3 A SB 16.3 C 8.5 A Initial Safety Screening Intersection Total 25.4 D 8.4 A To determine if a safety benefit is associated with the implementation of a roundabout at this location, a safety analysis was conducted using crash data obtained from the FDOT CARS database. Based on the past five years of crash data, 29 crashes (Table 3) occurred at the SR 29 / SR 82 intersection from 2007 through None of these 29 crashes resulted in fatal injuries. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 10

11 Table 3 Crash History for Location E Total Average Fatal Crashes Injury Crashes Property Damage Crashes Crash Totals For the five study years, the SR 29 / SR 82 intersection averaged crashes per million entering vehicles. This average crash rate is well in excess of the statewide average crash rates for this type of facility. For this reason, the average annual crash ratio of this intersection is in excess of 8.0. (Table 4) Table 4 Crash Rates and Ratios for Location E Average Crash Rate Statewide Crash Rate Crash Ratio Crash types were evaluated to determine which types are most prevalent and to estimate how many crashes might be eliminated by implementing roundabouts. This evaluation indicated the most prevalent crash type at this intersection is a rear-end crash (Exhibit 9). Angle, left turn and head-on collisions are severe crash types that each comprise 10% or more of the crashes at this location. Angle, left turn and head-on crash types are likely to be reduced by implementation of a roundabout. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 11

12 Exhibit 9 Crash Types for Location E Based on the Crash Modification Factors (CMF) Clearinghouse, two CMFs are associated with converting this intersection to a roundabout (Table 5). Additionally, one CMF was identified for signalizing the intersection. Table 5 Crash Modification Factors for Location E Countermeasure CMF Crash Severity Area Type Convert high speed rural intersection (3 leg) to roundabout 0.74 All Rural 0.28 Serious and Minor Injuries Rural Install a traffic signal 0.56 All Rural Appling these CMFs to the crash data provides an indication of how each intersection control type should affect crash rates. Signalizing the intersection is expected to reduce the crash ratio of the intersection by nearly 50%. Converting the intersection to a roundabout is also expected to reduce the crash ratio, but not as significantly as signalizing the intersection (Table 6). H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 12

13 Table 6 Potential Crash Rates for Location E Stop Controlled Signalized Roundabout Crashes/Year AADT 14,472 14,472 14,472 Crash Rate Statewide Crash Rate Crash Ratio Implementing a roundabout at Location 4 is also expected to reduce the severity of crashes occurring at this intersection. Based on the 5-year crash history, implementation of a roundabout at Location 4 has a potential safety benefit of $109,200 per year (Table 7). Assuming this annual benefit is constant over a 20 year span between the opening and design years, the safety benefit of the roundabout is estimated to be in excess of $2.1 million. Table 7 Potential Safety Benefit for Location E Geometric Screening Injury Crashes/Year 2.6 CRF (Severe Crashes) 0.28 Injury Crashes/Year Cost per Serious Injury $150,000 Annual Safety Benefit $109,200 Safety Benefit* (Life of Project) $2,184,000 *Based on 20 year design life of roundabout Conceptual designs were prepared for both signal and roundabout controlled intersections (Exhibit 10). These designs indicate that the roundabout intersection will require 0.33 acres more right of way than is necessary for the signal controlled intersection. Both intersections will impact wetlands, flood plains and the habitats of potentially threatened and/or endangered species, with impacts related to the roundabout being greater than those of the signalized intersection (Attachment B). Construction costs of the two intersections are assumed to be approximately equal, as the cost of the free flow lanes of the roundabout are expected to be offset by eliminating the need for signal equipment. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 13

14 Conclusions Location E is located in a rural area north of Immokalee. A multi-lane roundabout at this location will operate significantly better than a signalized intersection. The conceptual designs of both intersection types indicate the roundabout will require only 0.33 acres more right of way than that of the signalized intersection. A roundabout at this location is expected to reduce both the quantity and severity of crashes occurring at this location. Based on the crash evaluation, constructing a roundabout at this location can provide a $2.1 million safety benefit over the 20 year life of the roundabout. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 14

15 Signalized Intersection Exhibit 10 Conceptual Designs for Location E Roundabout H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 15

16 Location F: Proposed SR 29 at Existing SR 29 (East Alternatives) Two potential routes are being evaluated for a bypass of SR 29 around Immokalee. The southern termini of these routes intersect the existing SR 29 at different locations; however, both intersections utilize identical 2040 traffic volumes and lane configurations (Exhibit 11). The 2040 traffic volumes were obtained from the SR 29 Project Traffic Technical Memorandum, completed in September Exhibit 11 Volumes and Lane Configurations for Location F 2040 Volumes Signalized Roundabout Future Operational Screening Since the lane configurations and traffic volumes of Location F do not vary between East bypass alternatives, only one set of analyzes was prepared for these intersections. The HCM results indicate a roundabout at Location F would operate at LOS B or better under 2040 peak hour conditions (Attachment A). VISSIM results for this location indicate operating conditions of LOS A for the roundabout in the design year of A signal controlled intersection at Location F would operate at LOS C or better in both peak hours of Based on current LOS standards, this intersection should operate at LOS C or better. Initial Operational Screening No current operational data is available for this location as no intersection currently exists. Initial Safety Screening No safety data is available for this proposed intersection. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 16

17 Geometric Screening Conceptual designs for both a signalized and roundabout controlled intersection were prepared for comparison purposes. Exhibit 12 provides the conceptual designs for the intersections at the terminus of the East 1 Alternative route. Exhibit 13 provides the conceptual designs for the intersection at the southern terminus of the East 2 Alternative route. Both intersections of the East 1 Alternative route will require identical amounts of right of way. Both intersections will also have identical amounts of wetland and flood plain impacts (Attachment B). The construction costs of both intersections are believed to be approximately equal, as the circular roadway costs of the roundabout will be offset by the lack of need for turn lanes and signal equipment for a roundabout. No cost estimates were prepared for either concept. The conceptual designs for the East 2 Alternative route (Exhibit 13) are nearly identical to those of the East 1 Alternative route (Exhibit 12). Right of way, wetland, floodplain and species impacts do not vary between intersection control types. Wetland impacts of the East 2 Alternative are less than half of those associated with those of the East 1 Alternative. The construction costs associated with both the roundabout and the signalized intersection at this location are also assumed to be essentially equal. Conclusions The intersection at Location F lies at the terminus of a bypass intended to facilitate higher speed traffic flow around Immokalee. As roundabouts are intended to promote continuous but relatively slow moving traffic, utilization of a roundabout at this intersection contradicts the goal of constructing a higher speed bypass. The roundabout also does not provide any significant operational improvements over a signalized intersection. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 17

18 Exhibit 12 Conceptual Designs for Location F (East 1 Alternative) Signalized Intersection Roundabout H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 18

19 Exhibit 13 Conceptual Designs for Location F (East 2 Alternative) Signalized Intersection Roundabout H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 19

20 Location G: SR 29 at CR 846 (Central Alternative) The lane configuration of this intersection is identical to that of Location A. The traffic volumes of Location G vary slightly from those of Location A, but not enough to change the expected operating conditions. As such, all findings of Location A are applicable to Location G. Future Operational Analysis Refer to the evaluation of Location A. Initial Operational Analysis Refer to the evaluation of Location A. Initial Safety Screening Refer to the evaluation of Location A. Geometric Screening Refer to the evaluation of Location A. Conclusion The southbound volumes of this intersection are too large to be accommodated by a two lane roundabout. Based on this finding, no additional traffic analysis or screening is necessary. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 20

21 Location H: SR 29 at New Market Road (Central Alternative) This intersection varies slightly from that of Location B. The lane configuration and 2040 intersection volumes for Location H are provided in Exhibit 14. Exhibit 14 Volumes and Lane Configuration for Location I 2040 Volumes Signalized Roundabout Future Operational Analysis The HCS results for 2040 conditions with a roundabout indicate the intersection will operate at LOS F. An analysis of the intersection using VISSIM resulted in better operations, with LOS F (AM) and LOS B (PM) conditions in For comparison purposes, the signalized intersection is expected to operate at LOS F under 2040 conditions (Attachment A). Initial Operational Analysis No analysis of the existing conditions was performed. Initial Safety Screening No safety screening was performed for Location H. Geometric Screening No geometric screening was performed for Location H. Conclusion Location H is approximately 700 feet from Location G. Based on earlier findings, Location G should be signalized. Intersection control types should be consistent between Locations G and H, due to their close proximity to each other. For this reason, no additional traffic analysis or screening is necessary for Location H. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 21

22 Location I: New Market Road at Alachua Street (Central Alternative) This intersection is located within the town of Immokalee. The proposed roundabout would consist of a two-lane roundabout with raised splitter islands and a landscaped center island with a truck apron. The resulting intersection lane configurations are provided in Exhibit 15, along with 2040 intersection volumes obtained from the Project Traffic Technical Memorandum, completed in September Exhibit 15 Volumes and Lane Configuration for Location I 2040 Volumes Signalized Roundabout Note: Volumes entering and existing the southern leg of the intersection were estimated based on local land uses as no counts were available. At Location I, the north and south legs of Alachua Street are offset. This offset would be eliminated if a roundabout was implemented, but not if the intersection were signalized. Future Operational Screening Based on HCM methods, the roundabout controlled intersection is expected to operate at LOS F (AM) and LOS C (PM) in the 2040 peak hours. Due to the significant turning volumes associated with this intersection, a VISSIM analysis was also conducted for the roundabout. The VISSIM results indicate the roundabout would operate at LOS C or better under 2040 conditions (Attachment A). For comparison purposes, the intersection was also evaluated under signal control, the HCM results indicate a signalized intersection at Location I would operate at LOS F under 2040 conditions. Based on current LOS standards, Location I should operate at LOS D or better. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 22

23 Initial Operational Screening 2011 traffic data is not available for this intersection and therefore no operational analysis of the existing conditions was performed. Initial Safety Screening New Market Road and Alachua Street are not FDOT facilities. Crash data for non-fdot facilities is not readily available. For this reason, no crash analysis of this intersection is included in this study. Geometric Screening Conceptual designs for both the signalized and roundabout controlled intersection are provided in Exhibit 16. Both intersection types will require right of way; however, the roundabout will require significantly more right of way than the signalized intersection as the southern leg of the intersection must be realigned so it can be accommodated into the roundabout (Attachment B). Construction costs for the roundabout are expected to exceed those of the signalized intersection as the roundabout intersection includes relocation of the southern leg of the intersection into the roundabout. No cost estimates were prepared for either concept. Conclusions Location I is located within the limits of Immokalee. The two-lane roundabout evaluated at Location I provides significant operational improvements over that of a signalized intersection. The amount of right of way necessary for the roundabout is substantially greater than that of the signalized intersection. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 23

24 Signalized Intersection Exhibit 16 Conceptual Designs for Location I Roundabout H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 24

25 Location J: SR 29 at Central Loop (Central Alternative) This intersection is located north of Immokalee. The central alignment consists of a four lane SR 29 and a two lane Central Loop. The 2040 traffic volumes and lane configurations for Location J are provided in Exhibit 17. Exhibit 17 Volumes and Lane Configuration for Location J 2040 Volumes Signalized Roundabout Future Operational Screening The HCM results for Location J indicate the proposed roundabout will not meet the operating standard of LOS D (Attachment A). Initial Operational Screening A roundabout was not evaluated under existing conditions due to 2040 operating conditions. Initial Safety Screening No crash data was obtained for this location. Geometric Screening No conceptual designs for a roundabout at this location were prepared. Conclusions The intersection at Location J lies near the northern terminus of a potential bypass intended to facilitate higher speed traffic flow around Immokalee. As roundabouts are intended to promote continuous but relatively slow moving traffic, utilization of a roundabout at this intersection contradicts the goal of constructing a higher speed bypass. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 25

26 Location K: SR 29 at SR 82 (Central Alternative) Location K is identical to that of Location E. As such, the evaluation of Location K is identical to that of Location E. Future Operational Screening Refer to the evaluation of Location E. Initial Operational Screening No current operational data is available for this location as no intersection currently exists. Initial Safety Screening No safety data is available for this proposed intersection. Geometric Screening Refer to the evaluation of Location E. Conclusions Location K is located in a rural area north of Immokalee. A multi-lane roundabout at this location will operate significantly better than a signalized intersection. The conceptual designs of both intersection types indicate the roundabout will require only 0.33 acres more right of way than that of the signalized intersection. A roundabout at this location is expected to reduce both the quantity and severity of crashes occurring at this location. Based on the crash evaluation, constructing a roundabout at this location can provide a $2.1 million safety benefit over the 20 year life of the roundabout. H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 26

27 Recommendations This memorandum documents the roundabout feasibility study conducted for 12 intersections of the PD&E study of SR 29 from Oil Well Road to SR 82. In this study, roundabouts have been evaluated based on traffic operations, safety, right of way needs and wetland impacts. As a result of this evaluation, the following intersection types are recommended (Table 8). Table 8 Recommended Intersection Types Location A (SR 29 at CR 846) B (SR 29 at New Market Road) C (SR 29 at 1 st Street) D (SR 29 at 9 th Street) E (SR 29 at SR 82) F (Proposed SR 29 at Existing SR 29) G (SR 29 at CR 846) H (SR 29 at New Market Road) I (New Market Road at Alachua Street) J (SR 29 at Central Loop) K (SR 29 at SR 82) Intersection Type Signalized Signalized Signalized Signalized Roundabout Signalized Signalized Signalized Roundabout Signalized Roundabout H:\PD&E\D1\2484_SR29\Roundabout Feasibility\Roundabout Feasibility Memo.doc 27

28 Attachment A Preliminary Roundabout Feasibility Screening Results (Based on 2040 Design Year) SR 29 PD&E Study (FPN ) Alternative ID Intersection Approach HCM Results - AM Approach Delay Overall Delay (sec/veh) / LOS (sec/veh) / LOS Roundabout Analysis Results HCM Results - PM VISSIM Results - AM Approach Delay Overall Delay Approach Delay Overall Delay (sec/veh) / LOS (sec/veh) / LOS (sec/veh) / LOS (sec/veh) / LOS VISSIM Results - PM Approach Delay Overall Delay (sec/veh) / LOS (sec/veh) / LOS Signalized Analysis Results HCM Results - AM HCM Results - PM Approach Delay Overall Delay Approach Delay Overall Delay (sec/veh) / LOS (sec/veh) / LOS (sec/veh) / LOS (sec/veh) / LOS SR 29 - EB 66.9 / F 17.8 / C A SR 29 at CR 846 SR 29 - WB 39.5 / E 52.0 / F 74.6 / F / CR SB 24.4 / C / F F B SR 29 - EB / F 17.2 / C 21.9 / C 11.1 / B 12.0 / B 5.2 / A SR 29 at New Market SR 29 - WB 18.5 / C 73.8 / F 73.2 / F 52.2 / F 8.5 / A 14.8 / B 17.0 / C 15.4 / C 16.9 / B 17.2 / B 23.2 / C 20.1 / Rd New Market Rd - SB 34.2 / D 43.7 / E 9.7 / A 18.6 / C 26.7 / C 34.6 / C C Existing Alternative SR 29 - EB / F / F 33.0 / D 11.1 / B SR 29 - WB 56.2 / F / F 50.6 / F / F C SR 29 at 1st St / F / F 68.4 / F / 1st St - NB / F / F / F / F 1st St - SB 79.4 / F / F 57.1 / F 47.7 / E F SR 29 - EB / F 23.5 / C 11.9 / B 8.4 / A SR 29 - WB 19.9 / C / F 15.2 / C / F D SR 29 at 9th St 62.8 / F 77.9 / F 16.6 / C 52.5 / F 9th St - NB 46.0 / E 38.1 / E 39.3 / E 18.3 / C 9th St - SB 15.8 / C 29.1 / D 9.8 / A 25.8 / D SR 82 - EB 11.7 / B 7.4 / A 3.2 / A 2.2 / A 74.7 / E 38.2 / D E SR 29 at SR 82 SR 29 - NB 53.0 / F 44.1 / E / F / F 5.2 / A 4.9 / A 8.0 / A 8.0 / A 42.6 / D 45.6 / D 42.0 / D 44.5 / SR 29 - SB 35.7 / E 65.4 / F 8.6 / A 22.2 / C 41.5 / D 57.7 / E D East Alternative 1 or 2 F SR 29 at Eastern Loop SR 29 - EB 15.2 / C 8.4 / A 3.5 / A 2.5 / A 37.4 / D 22.9 / C SR 29 - NB 7.4 / A 10.2 / B 10.0 / A 9.4 / A 2.0 / A 2.4 / A 2.0 / A 2.1 / A 10.2 / B 21.1 / C 8.5 / A 13.3 / B Eastern Loop - SB 9.4 / A 8.9 / A 2.0 / A 2.0 / A 20.3 / C 17.0 / B SR 29 - EB 90.6 / F 20.3 / C G SR 29 at CR 846 SR 29 - WB 54.6 / F 70.4 / F / F / CR SB 29.9 / D / F F H SR 29 - EB / F 30.5 / D / F 13.8 / B 27.7 / C 18.0 / B SR 29 at New Market SR 29 - WB 74.2 / F / F / F / F 4.1 / A 78.0 / F 5.2 / A 10.2 / B / F 96.4 / F / F 87.3 / Rd New Market Rd - SB / F / F 17.7 / C 16.7 / C 30.4 / C 40.6 / D F Central Alternative I New Market Rd at Alachua Street New Market Rd - EB 43.6 / E 30.9 / D 18.4 / C 20.8 / C / F / F New Market Rd - WB 4.1 / A 2.0 / A 4.5 / A 5.1 / A 97.9 / F 93.7 / F 91.9 / F 18.3 / C 19.3 / C 10.9 / B / F Alachua Street - NB 27.4 / D 19.4 / C 60.1 / F 36.2 / E 53.8 / D / F Central Loop - SB / F 31.3 / D 27.4 / D 9.6 / A / F / F / F J SR 29 at Central Loop (North) SR 29 - EB / F 26.2 / D Central Loop - WB 23.1 / C 80.4 / F / F / SR 29 - NB 71.8 / F 53.1 / F F SR 82 - EB 11.7 / B 7.4 / A 2.6 / A 2.4 / A 74.7 / E 38.2 / D K SR 29 at SR 82 SR 29 - NB 53.0 / F 44.1 / E / F / F 5.0 / A 4.8 / A 10.0 / A 9.7 / A 42.6 / D 45.6 / D 42.0 / D 44.5 / SR 29 - SB 35.7 / E 65.4 / F 9.9 / A 26.7 / D 41.5 / D 57.7 / E Note: Level of service (LOS) letter grades assigned based on the 2010 Highway Capacity Manual, Exhibit 21-1: LOS criteria for automobiles in roundabouts. D

29 Attachment B Draft Roundabout Alternatives Evaluation Matrix SR 29 PD&E Study (FPN: ) Evaluation Factors Location F (East 1) Location F (East 2) Location I Locations E & K Standard Roundabout Standard Roundabout Standard Roundabout Standard Roundabout SATISFACTION OF PURPOSE AND NEED Yes Yes Yes Yes Yes Yes Yes Yes PROPOSED RIGHT OF WAY (acres) BUSINESS PARCELS AFFECTED RESIDENTIAL PARCELS AFFECTED OTHER PARCELS AFFECTED (includes industrial, government, institutional, etc.) CHURCHES AFFECTED SCHOOLS AFFECTED PARKS [SECTION 4(f)] POTENTIALLY AFFECTED CULTURAL RESOURCES AFFECTED Potential Eligible Structures (#) Historic Districts / number of contributing structures (#/#) Eligible/Potentially Eligible Historic Structures/Districts Potentially Adversely Affected (#/#) TOTAL WETLANDS (acres) Forested (acres) Herbaceous (acres) FLOODPLAINS (acres) POTENTIAL THREATENED AND ENDANGERED SPECIES INVOLVEMENT Primary Panther Habitat (acres) Secondary Panther Habitat (acres) Presence of suitable scrub jay habitat (H/M/L) POTENTIAL CONTAMINATION SITES AFFECTED (# High/# Medium/# Low) / 0 / 1 0 / 0 / 1 1 / 0 / 1 1 / 0 / WETLAND MITIGATION COSTS $ 447, $ 447, $ 186, $ 186, $ 779, $ 966, PANTHER MITIGATION (PHU) COSTS $ 78, $ 78, $ 90, $ 90, $ 36, $ 45, DESIGN (in millions) RIGHT-OF-WAY (in millions) CONSTRUCTION (in millions) CONSTRUCTION ENGINEERING AND INSPECTION (in millions) TOTAL COSTS