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

around 2,000 pcphpl. U.S. 61 to the north will have lesser volumes but will still contribute to the
amount of traffic that will flow through the interchange. The volumes on I-70 and I-64 alone will
be operating at LOS D to E. It is anticipated that merging and diverging movements to and from
the ramps will cause frictional effects on the through lanes and worsen their LOS to E or capacity.
From I-64 to Lake Saint Louis Blvd. volumes will drop to 100,000 in six lanes as I-64 will drain off
some traffic. Applying the above daily and directional factors results in 5,000 vehicles during the
peak hours in the high direction of travel which gives 1,700 vehicles per lane. Factoring for pcphpl
gives about 1,800. From Table 10 and a 60 mph speed limit, this results in LOS D with some
congestion. From Lake Saint Louis Blvd. to Bryan Rd., volumes will be slightly higher but
congestion will be about the same.
From Bryan Rd. to Rt. 79, traffic builds up substantially, because of the sizeable amount of
development that is expected to occur in this part of the county. East of Bryan Rd. to Rt. K volumes
will increase to 125,000 on three lanes in each direction. Applying the daily and directional factors
results in 2,050 vehicles per lane. Factoring for pcphpl gives 2,200. From Table 10 and a 60 mph
speed limit, it will operate at LOS E with considerable congestion. The opposite direction will have
about 1,700 vehicles and planning factors indicate 1,800 pcphpl. Table 10 indicates LOS D with
moderate congestion.
Traffic volumes east of Rt. K will also rise and reach 145,000 vehicles. However, an additional
through lane, in each direction, will be added making it four lanes. Applying the daily and
directional factors gives 1,800 vehicles per lane. Factoring for pcphpl gives 1,900 vehicles or the
high end of LOS D. This section will operate with considerable congestion. Traffic in the opposite
direction will operate at the low end of LOS D with only minor congestion.
T.R. Hughes will add a small amount of traffic and have four lanes in each direction to Rt. 79. The
LOS will be slightly worse with the high direction of travel reaching capacity (LOS E) with severe
congestion. The opposite direction will be LOS D with moderate congestion.
East of Rt. 79 volumes will rise substantially to about 175,000 to Mid Rivers Mall Dr. It will have
four lanes in each direction, however, an auxiliary lane will be added for eastbound traffic. This will
aid travel between the two interchanges especially during the morning peak hours. Applying daily
and directional factors and adjusting for the auxiliary lane gives 1,850 vehicles in the through lane.
Factoring for pcphpl gives 1,950 vehicles. From Table 10 and a 60 mph speed limit this equates to
the high end of LOS D. Considerable congestion can be expected for eastbound traffic between
these interchanges as it does today. In the opposite direction there will be no auxiliary lane, only
four through lanes. During the afternoon peak hours volumes will reach 2,200 vehicles per lane or
the capacity of the road at LOS E. It will operate with severe congestion similar to what is occurring
today with backups extending from Rt. 79 through Mid Rivers Mall Dr.
From Mid Rivers Mall Dr. to Rt. 370, I-70 widens to six lanes in each direction for the multiple on
and off ramps to Rt. 370. The ADT in this section will be about the same with 175,000 vehicles.
After applying all the adjustment factors it was determined that the pcphpl volumes from Table 10
would operate at LOS D due to the additional lanes. However, these numbers do not take into
account congestion from two other sources; that described above from the adjacent section to the
west and the other from weaving traffic to and from the Mid Rivers Mall Dr. interchange.
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