St. Charles County Transportation Plan 2030 - East-West Gateway ...

U.S. 40/61
U.S. 40/61 from west of Rt. K to Rt. N handles about 50,000 vehicles per day. It has a speed limit
of 55 mph and a limited number of intersections until the signal at Rt. N. A section about a mile and
a half long is up to Interstate standards through the Winghaven Blvd. interchange. During the
morning peak hour it handles about 5,000 vehicles with 3,000 eastbound and 2,000 westbound.
Adjusting for trucks (6.8 percent), rolling terrain, and other factors gives a passenger equivalent for
eastbound of 3,300 or 1,650 vehicles per lane. This equates to LOS D. Westbound traffic is around
2,200 or 1,100 per lane and LOS C. From Rt. N to I-70, has volumes’ area about 35,000 per day
with a speed limit of 55 mph. Two signals exist. One at Callahan Rd. and one at Prospect Rd. and
other intersections also exists. A section about a mile and a half long, is Interstate through the Lake
Saint Louis Blvd. interchange. During the morning peak hour there are 3,500 vehicles with about
2,100 eastbound and 1,400 westbound. Adjusting for trucks, rolling terrain and traffic signals brings
the pcphpl to about 2,300 and 1,600 or about 1,200 per lane in the peak direction and 800 in the
other. This is equal to LOS of C and B respectively. During the afternoon, traffic volumes are the
same as the morning and the volumes and LOS are the same, C for westbound and B for eastbound.
B-5.3. Principal Arterials
Operating conditions on Principal Arterial roads are poorer than on Interstates, Freeways, or
Expressways. In urban and suburban areas they can be four, five, or six lanes, divided or undivided
roads. In rural areas they can be two, three, or four lane roads. Traffic flow and LOS are controlled
by their traffic volumes and number of signalized intersections, side streets, and entrances, and the
number of vehicles turning to and from them.
The HCM 2000 provides guides for estimating LOS for planning purposes on Principal Arterial roads.
The data required are average travel speeds, the number of signals per mile, and the LOS of
signalized intersections. Average travel speeds came from the Council’s GPS travel time runs. The
number of signals came from the road inventories. The LOS of signalized intersections came from
field observation’s following the criteria described in Chapter 16 - Signalized Intersections, of the
HCM 2000. The LOS for most of the Principal Arterials fall into this category and are discussed
below.
Rt. 79
Rt. 79 from I-70 north past the Salt River Rd./Pearl Dr. carried about 22,000 vehicles and operated
at LOS C during the peak hours. Backups occur for northbound traffic during parts of the afternoon
peak hour where it necks down from four to two thus reducing the LOS to F for a short section.
North of there it has some left turn lanes for a signalized intersection at T.R. Hughes Blvd. and a few
at non-signalized intersections. Volumes drop northward until it reaches Lincoln County where it
carried about 13,000 vehicles. Average speeds were about 47 mph for northbound and southbound
traffic during the morning peak hours. This placed it at LOS C. During the afternoon peak hour,
northbound traffic averaged 43 mph placing it at LOS D and southbound traffic had an average
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