Initial Study MND - Sonoma County Agricultural Preservation and ...

More documents

Recommendations

Info

Taylor MountainINITIAL STUDY/MITIGATED NEGATIVE DECLARATIONc. Would the project result in a change in air traffic patterns, including either an increase intraffic levels or a change in location that results in substantial safety risks?NO IMPACT. No operating airports or heliports are within two miles of the project site. Theproposed project would not include any features that would have the capacity to impact airtraffic.d. Would the project substantially increase hazards because of a design feature orincompatible uses?LESS THAN SIGNIFICANT. There are no unusual conditions that represent obvious safety hazards.While the proposed project would increase the number of vehicle trips on roads in the projectarea, vehicles would not be exposed to increased hazards as result of the project. Designfeatures of the proposed staging areas would not cause roadway hazards, and no incompatibleuses would occur. To reach this conclusion, a comprehensive review of collision hazards andsight distance conditions was conducted.Sight DistanceSight distance along Petaluma Hill Road at the Preserve’s proposed driveways was evaluatedbased on sight distance criteria contained in A Policy on Geometric Design on Highways andStreets published by American Association of State Highway and Transportation Officials(AASHTO). These guidelines include recommended sight distances at intersections, includingstopping sight distances for drivers traveling along the major approaches and for drivers ofstopped vehicles at the minor street approaches and driveways. These recommendations arebased upon approach travel speeds, and take into account which direction a vehicle would turnonto the major approach, with greater sight distance needed for the more time-consuming taskof turning left as compared to turning right.Sight distance at the northern and southern driveway locations were field measured. Based ona design speed of 55 mph, which is the posted speed limit on Petaluma Hill Drive along thePreserve’s frontage, the northern driveway marginally meets sight distance requirements for allmovements. However, this driveway will be restricted to allow only right-turn movements. Atthe southern driveway, where left-turns would be allowed, sight lines would be adequate for allmovements. Accordingly, since the northern driveway is proposed to be limited to right turnaccess, no further changes to access at this location are recommended.Since the Farmers Lane Extension did not exist at the time of this analysis, it was not possible tofield-measure the required sight lines at the proposed driveway. Therefore, Master PlanStandard 200 states that when the proposed driveway connecting to the Farmers LaneExtension is designed, it will need to be designed in a manner that ensures that adequate sightlines are provided.CollisionsThe collision history for the study area was reviewed to determine any trends or patterns thatmay indicate a transportation safety issue. Since collision analysis is dependent on historicdata, only the following intersections that currently exist were included in the analysis:Final B-116 September 2012
Taylor MountainINITIAL STUDY/MITIGATED NEGATIVE DECLARATION Petaluma Hill Road/Kawana Springs Road Kawana Springs Road/Franz Kafka Road Kawana Terrace/Meda Avenue Farmers Lane Extension-Sonoma Academy Entrance/Kawana Springs Road 8Of these four intersections, collisions were reported only at Petaluma Hill Road/Kawana SpringsRoad, with the other intersections having no reported collisions for the five-year period of April1, 2005 through March 31, 2010 studied. The calculated collision rate for Petaluma HillRoad/Kawana Springs Road was compared to the average collision rate for similar facilitiesstatewide. During the five-year period, a total of 25 collisions were reported at Petaluma HillRoad/Kawana Springs Road, resulting in a calculated collision rate of 0.63 collisions per millionvehicles entering the intersection (c/mve), which is greater than the statewide average of 0.43c/mve. None of the reported collisions resulted in a fatality, but 19 resulted in one or moreinjuries. The majority of the reported collisions (17, or 68 percent of total collisions) involvedone or more drivers making a left-turn movement at the intersection, where all approaches arecontrolled with protected-permissive left-turn signal phasing (i.e., where a left-turn arrow isprovided for “protected” movements, but drivers can also turn when left-turn arrow is off, andthe green “ball” light is on, when a safe gap in oncoming traffic is present). Based ondiscussions with City of Santa Rosa staff (Sprinkle, 2012), the City is considering modifying thesignal to provide a flashing yellow left-turn arrow on the approaches with protected-permissiveleft-turn phasing. This yellow light would flash when permissive left-turns are allowed (i.e.,when left-turning drivers are allowed to proceed when there is an adequate gap in oncomingtraffic) with the goal of reminding drivers that that oncoming traffic has the right-of-way. Thismay be effective in reducing left-turn related collisions. At the time of this analysis, the City isconsidering this modification and has not made a decision. During the same five-year period,the study segment of Petaluma Hill Road that includes this intersection (i.e., from YolandaAvenue to Hopi Trail, south of the property) had a total of 19 reported collisions, resulting in acalculated collision rate of 0.66 collisions per million vehicle miles travelled (c/mvm), which isless than the statewide average of 1.17 c/mvm for similar facilities.The addition of project-generated traffic is not anticipated to increase the average collision rateon Petaluma Hill Road or at the intersection of Petaluma Hill Road/Kawana Springs Road. Theincrease in traffic would be moderate, with the projected addition of 273 weekday dailyvehicles on Petaluma Hill Road, or about two percent. There are several factors that potentiallyaffect collisions rates, including roadway capacity, design and geometry, sight distance, trafficvolumes, speed, and lighting. The proposed project includes design features such as turningbays and traffic control elements that are focused on reducing the potential for vehicularconflicts and the accommodation of increased traffic.8Since this intersection does not currently exist, collision records for the existing intersection of Kawana SpringsRoad and the entrance to Sonoma Academy were checked.September 2012 B-117 Final
Page 3:
Taylor Mountain Regional Park and O
Page 6:
Taylor MountainINITIAL STUDY/MITIGA
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78: Taylor MountainINITIAL STUDY/MITIGA
Page 127: Taylor MountainINITIAL STUDY/MITIGA
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
show all

Initial Study MND - Sonoma County Agricultural Preservation and ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?