2007

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2006 Congestion Report - Seattle to Bellevue (via SR 520)

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 Bellevue to Seattle via I-5, SR 520 and I-405 graph shows 2005 data peaking around 83% between 7:30 a.m. and 8:45 a.m. compared to 2003 data that shows peaks around 60% between 7:45 a.m. and 8:45 a.m. Afternoon Bellevue to Seattle via I-405, SR 520 and I-5 shows 2005 data starting at 35% at 3 p.m., peaking at 95% at 5:30 p.m. and decreasing to around 50% at 7 p.m. compared to 2003 data starting at 25% at 3 p.m., peaking at 88% at 5:30 p.m. and decreasing to around 35% at 7 p.m.

The graph below displays highway productivity for a specific point 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.

SR 520 Floating Bridge graph shows 2005 data dropping to a low of 55% around 10:15 a.m. bewteen 7 a.m. and 10:30 a.m. and to a low of 50% at 6:30 p.m. bewteen 2:30 p.m. and 7 p.m. The 2003 data is almost identical with slight time offsets being seen.

 

  Seattle to
Bellevue AM 		Bellevue to
Seattle PM
Route I-5/SR 520/I-405 I-405/SR 520/I-5
Peak time 7:50 am 5:35 pm
Length 10.1 miles 10.5 miles
Travel time at posted speeds 11 minutes 11 minutes

Average Peak Travel Time 2003

18 minutes 22 minutes
Average Peak Travel Time 2005 23 minutes 28 minutes
Average Peak Travel Time Change, 2003-2005 28% 27%
95% Reliable Travel Time 2003 26 minutes 28 minutes
95% Reliable Travel Time 2005 35 minutes 37 minutes
95% Reliable Travel Time Change, 2003-2005 35% 32%
Ratio of Peak Travel Time to Maximum Throughput Travel Time (MT³I) 2003 1.4 1.8
Ratio of Peak Travel Time to Maximum Throughput Travel Time (MT³I) 2005 1.8 2.3
Traffic Volume Peak Hour Change -2% 0%
Duration of Peak Period, 2003 (hours:minutes) 2:05 4:10
Duration of Peak Period, 2005 (hours:minutes) 2:40 4:50
Change (in minutes) 35 40

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