Aldridge Transportation Consultants, LLC Advanced Transportation Planning and Traffic Engineering

Transcription

1 Advanced Transportation Planning and Traffic Engineering John M.W. Aldridge, PE, PTOE, AICP 1082 Chimney Rock Road Colorado Licensed Professional Engineer Highlands Ranch, CO Mobile: April 2, 2018 Mr. Eric Wernsman Wernsman Engineering and Land Development, LLC nd St. Evans, CO RE: Traffic Impact Analysis Revised Expedition Water Solutions #6 Site Weld County, CO Dear Mr. Wernsman: This technical letter provides an analysis of the potential impact occasioned by an approximately 30-acre saltwater disposal site on the east side of WCR-19 about equidistance between WCR-20 and WCR-18. The site lies approximately 3 miles east of Firestone. The aerial photo shows the location and on the site. The site will be accessible from one location on WCR-19 toward the south end of the site. There are no crossroads within ½ mile of the site access. The saltwater disposal facility will employ up to 10 persons per 24-hour period (3 per shift). It will process a maximum of 100 trucks per day spread out over a 24-hour period. The weekday average number of trucks is about 80. Existing Conditions In this area, WCR-19 is a two-lane paved collector roadway that carries 1,284 vehicles per day according to the Weld County 2035 Transportation Plan. The plan reports that it is 24 feet wide and in good condition. The plan indicates that the capacity of the roadway is 4,600 ADT. Impacts Trip Generation The following table show the type of vehicle and number of average daily round trips. Type of Vehicle Average Number of Round Trips/Day a) Passenger cars/pickups 10 b) Tandem Trucks c) Semi-Truck/Trailer/RV 80

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3 Expected Vehicle Routes and Trip Distribution Aldridge Transportation Consultants, LLC Page 3 of 5 According the operator of the facility, the trucks will split about 50/50 to/from the north and south of the site on WCR-19. This is based on the general location of the wells that they will serve. Peak Hour of Usage The facility operates on a 24-hour basis and as such there is no typical peak hour of usage that being the peak hour of the adjacent street between 7 and 9 AM and 4 and 6 PM. Generally, trucks will start loading water after 7 AM and not arrive at the disposal site to unload water until after 9 AM. There may be shift changes with a couple of workers during the morning peak hour likely using passenger car or pick-up trucks. During the afternoon peak hour (4 to 6 PM) there may be another shift change. Trucks in an out during that time are random and unpredictable. Nonetheless, for analysis purposes, a standard 10 percent of average daily traffic is assumed. At 10 percent of the average daily, this equates to 9 trips entering and 9 trips exiting the facility. 4-5 vehicles will enter and exit to/from the north and 4-5 vehicles will enter and exit to/from the south. Note that passenger car equivalents (pce) are not applicable to the turning volume warrant in this case. The left turn lane volume warrants in standard traffic engineering documents do not differentiate cars from trucks. Passenger car equivalents are more appropriately used to determine the length of queues and design of storage lanes. Furthermore, a left turn lane can be dropped if the opposing volume is equal to or less than 100 vehicles per hour. In this case, assuming the peak hour is 10 percent of the daily (1,284 ADT) and a standard 55/45 directional split, the maximum opposing volume is approximately 70 vehicles per hour. The sight distance is adequate for both the stopping sight distance and for vehicles entering the roadway, particularly looking to the south. The crest of the hill is approximately 1,200 feet. For a multi-unit vehicle entering a 55-mph two-lane roadway, the required distance is 935 feet. Mitigation Based on the above information, the owner/operator of the facility agrees to the improvement triggers below: a) 200 vpd or significant dust as identified by County-Mag-Chloride dust abatement b) 300 vpd alternative pavement c) 400 vpd pavement

4 Page 4 of 5 The vehicles per day triggers are not applicable as WCR-90 is paved. d) 10 vph during peak hour turning left into the facility left turn deceleration lane e) 25 vph during peak hour turning right into the facility right turn deceleration lane f) 50 vph during peak hour turning right out of the facility right turn acceleration lane. The vehicles per hour trigger for auxiliary lanes are not met. Conclusions Based on this analysis, the present roadway surface, access configuration, and traffic control will adequately handle, without improvements, the truck traffic generated by the saltwater disposal facility. Should you have any questions or need additional information please call me at Respectfully submitted: Aldridge Transportation Consultants, LLC John M.W. Aldridge, P.E. Principal JMWA/me/attachment ATC is professional service firm specializing in traffic engineering and transportation planning. ATC s principal, John M.W. Aldridge, is a Colorado licensed professional engineer. In the past 20 years, ATC has prepared over 1,000 traffic impact studies, designed over 100 traffic signals, and has provided expert witness testimony on engineering design and access issues on multi-million-dollar interchange and highway projects in Kansas and Colorado.

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