2006

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2006 Congestion Report - Seattle to Issaquah

The two graphs below display the percent of days on each route when traffic speeds fell below 35 mph. The darker line shows data for 2005. The lighter line shows data for 2003.

Morning Seattle to Issaquah via I-5 and I-90 graph shows 2005 data peaking around 15% between 8:30 a.m. and 9 a.m. compared to 2003 data that shows approximately 5% between 7:45 a.m. and 10 a.m. Afternoon Issaquah to Seattle via I-90 and I-5 graph shows 2005 data peaks of 40% at 5:30 p.m. compared to 2003 data peaks of just over 20% for the same time period.

The graphs below display highway productivity for specific points along this route. When the line is at 100%, the maximum number of vehicles per hour are travelling through this point. Any time the line dips below 100%, the system is not operating at 100% efficiency.

I-5 at I-90 graph shows 2005 data dropping to around 30% between 6:30 a.m. and 12 p.m. and to a low of 40% at 6:45 p.m. bewteen 2:30 p.m. and 7 p.m. compared to 2003 data of lows around 45% between 6:30 a.m. and 12 p.m. and 50% between 2:30 p.m. and 5 p.m. and 60% between 5 p.m. and 7 p.m.

I-90 at SR 900 in Issaquah graph shows 2005 data dropping to around 50% at 8:30 a.m. between 6:45 a.m. and 9 a.m. compared to 2003 data that shows lows of 60% at 8 a.m. between 7:15 a.m. and 8:15 a.m.

 

  Seattle to
Issaquah AM
Issaquah to
Seattle PM
Route I-5/I-90 I-5/I-90
Peak time 7:45 am 5:35 pm
Length 15.5 miles 15.5 miles
Travel time at posted speeds 16 minutes 15 minutes

Average Peak Travel Time 2003

19 minutes 22 minutes
Average Peak Travel Time 2005 21 minutes 26 minutes
Average Peak Travel Time Change, 2003-2005 11% 18%
95% Reliable Travel Time 2003 23 minutes 33 minutes
95% Reliable Travel Time 2005 26 minutes 45 minutes
95% Reliable Travel Time Change, 2003-2005 13% 36%
Ratio of Peak Travel Time to Maximum Throughput Travel Time (MT³I) 2003 1.0 1.2
Ratio of Peak Travel Time to Maximum Throughput Travel Time (MT³I) 2005 1.2 1.4
Traffic Volume Peak Hour Change 5% 4%
Duration of Peak Period, 2003 (hours:minutes) * *
Duration of Peak Period, 2005 (hours:minutes) n/a 0:45
Change (in minutes) n/a *

* = Speeds did not drop below 35 mph for any siginificant amount of time for this route.