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<br /> <br /> <br />3 of 7 <br /> <br /> <br />Traffic speed data on Foothill Road is collected on a regular basis. Over the last 15 years, the <br />speed has been consistent with 85% of drivers driving at or below 45 mph and 99% of vehicles <br />driving below 55 mph. <br /> <br />Sight Distance <br />The sight distance to the south is 630 feet. This distance is measured from the proposed <br />project driveway to the point where a vehicle is first visible as it comes around the curve at Puri <br />Court. <br /> <br />The approximate sight distance to the north is 550 feet. This distance is measured from the <br />proposed project driveway to the top of the vertical curve located at Equus Court. The sight <br />distance looking to the north may improve with the project, as the trees lining the roadway will <br />be removed, which could add 30-40 feet of sight distance. <br /> <br />• Stopping Sight Distance 1 for a vehicle traveling at 45 mph is 360 feet. <br />• Intersection Sight Distance 2 for 45 mph is 500 feet. <br /> <br />Thus, the visibility to the north and the south meets the required intersection sight distance of <br />500 feet. <br /> <br />The Federal Highway Administration’s (FHWA) Handbook for Designing Roadways for the <br />Aging Population evaluated intersection sight distance for ages 55-80 years old. The handbook <br />provides greater detail on intersection sight distance and the concept of gap acceptance for <br />older drivers, in particular suggesting that older drivers need a larger gap between vehicles to <br />feel comfortable making left turns. It notes that for the average driver, an acceptable gap in <br />vehicles is 5.5 seconds, meaning that a typical driver wanting to turn left onto a roadway will <br />want 5.5 seconds between vehicles. This time between vehicles progresses linearly with age, <br />and older drivers (75+) may need up to 8 seconds to have a comfortable gap for left turns. <br />Although field observations conducted by the FHWA identifies a metric of 5.5 seconds, the <br />accepted standard for intersection sight distance evaluation uses a larger 7 second gap. This <br />larger gap provides easier access for larger vehicles (delivery vehicles) and older drivers that <br />exercise caution and turn at a slower speed. <br /> <br /> <br />1 This value is used for drivers on Foothill Road to recognize an object in the roadway and come to a stop before striking it. <br />2 This number is used to determine the distance needed for a vehicle exiting a side street to look left, right and left again to <br />make a left turn onto Foothill Road.