While Cheney streets and intersections can seem very busy at times, according to a recently completed traffic study, volumes on arterials and intersection wait times are within established national and regionals norms for this size city - at least for awhile.
City staff presented the study information to the Cheney Planning Commission as part of their comprehensive plan review process, which is currently focused on the plan's transportation chapter. While the information presented painted an interesting picture of city traffic - and its future - Public Works Director Todd Ableman stressed to the commission that what was presented on Monday, Sept. 12, was a draft, and that more information would be available for the commission's review at their Oct. 10 meeting.
The plan looked at traffic conditions on seven minor arterials: State Route 904/First Street, Betz, Cheney-Spokane, Cheney-Spangle and Mullinix roads along with Washington and Fourth streets. It also looked at eight major collectors: Cheney-Plaza Road, Mike McKeehan Way, Simpson Parkway and North Sixth, Elm, F, K and Pine streets.
Using national highway standards and formulas, the study determined traffic volume capacity for all 15 streets, while electronic and visual observations during a peak hour of 4:30 – 5:30 p.m. last spring produced average daily trip (ADT) volumes. All but four streets fell within acceptable volume to capacity ratio of .80 or less, meaning the average daily volumes were at 80 percent of the roadway's capacity.
The exceptions were two minor arterial sections, SR 904 north of Betz Road and Betz west of SR 904. The former has a capacity of 18,600 but an ADT of 18,270, putting it at 98 percent of capacity, with 100 percent or more constituting a concern.
The study determined there was not much room for traffic growth on SR 904 north of Betz, and even worse outside the city limits where heavy traffic meant minor spacing between vehicles and where unexpected slowdowns carried potential for serious accidents. The study also noted that even at high density, traffic still moved within the speed limits.
"Although, when you get on 904 and Betz it does seem to be bumper to bumper," Ableman said.
Betz west of SR 904 was at 80 percent, with an ADT of 12,390 and capacity of 15,500. Of the major collectors, only the section of North Sixth Street south of Betz exceeded the 80 percent, coming in at 81 percent of capacity with 4,860 ADT and 6,000 capacity.
Population growth rates for Cheney, which also include projected enrollment growth at Eastern Washington University, estimate the city's population at about 23,500 by the year 2040, with an associated increase in single- and multi-family developments to accommodate the increase. That growth carries associated traffic increases, putting four minor arterial sections over acceptable volume to capacity ratios.
The worst of these is SR 904 north Betz, not only tabbed to carry 29,000 ADTs by 2040 but 22,100 by 2022, putting it 3,100 average daily trips over capacity within six years.
Also projected to be over capacity by 2040 is SR 904 north of Cheney-Spangle Road and Betz Road west of SR 904, while SR 904 south of Cheney Spokane will be at 100 percent of its 31,700 ADT capacity. SR 904 north of Cheney-Spangle and south of Cheney-Spokane will be at 92 percent and 76 percent of capacity by 2022, while the Betz Road section will be at 98 percent of capacity within six years.
The study also analyzed 11 high-volume intersections within the city, using standards and formulas to determine service levels that conform to delay times at each intersection. As an example, the highest LOS (level of service) intersection would have a wait time of 10 seconds or less, with or without a signal, while the lowest LOS of F carried wait times of greater than 80 seconds with a signal, and greater than 50 seconds without.
A LOS of D, greater than 35 – 55 seconds with signal and 25 – 35 without, is the acceptable limit for Cheney intersections. At present, none of the studied intersections exceeded the D LOS.
Projecting forward five and 30 years changes that, however. By 2021, the non-signal Betz Road and North Sixth Street intersection slides to an LOS F, with wait times of 58.3 seconds, increasing to 64.1 seconds by 2040.
In 2040, it's joined by SR 904 and Simpson Parkway, SR 904 and Pine Street and SR 904 and Cheney-Plaza Road, all with projected levels of service of E, carrying wait times ranging from 38 seconds to 66 seconds at Simpson Parkway.
The study also looked at intersections and driveways prone to accidents. Of the 271 collisions occurring in Cheney between Jan. 1, 2013 and July 6, 2016, nine took place at Betz Road and Silverthorne Lane, an area that includes an entrance/exit from Cheney Plaza shopping center.
Of the 108 injuries from collisions citywide during that time frame, the six accidents at North Sixth Street and Simpson Parkway accounted for 10.
Ableman said they would look at improving the signage at these intersections as one way of decreasing the number of accidents. He noted the study recommended a smaller 100-foot diameter urban roundabout as one method of reducing Betz and North Sixth wait times.
John McCallum can be reached at jmac@cheneyfreepress.com.
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