A dramatic change in the observed travel speeds on limited-access highways occurred in the morning peak period. The table illustrates that between the data collection in the mid-1990s and the collection at the end of the decade, there was an increase of approximately 8 percentage points in the number of roadways experiencing travel congestion during the morning peak period (congestion being defined as an average observed travel speed of less than 50 mph). However, the monitoring results for the evening period indicate that overall congestion for that time of day did not significantly change from the earlier to the later collection period: the same percentage of the highway network had average travel speeds of less than 50 mph in 1999–2000 as five years earlier.

The figures below illustrate the segments of the monitored limited-access highways where observed travel speeds decreased between the 1994–1995 and 1999–2000 monitoring periods. The maps highlight the locations where an increase or decrease of 5 mph or more in average observed speeds occurred between the two periods.

Click here for a map that shows the speed changes on the monitored limited-access highway network in the morning peak period.

Click here for a map that shows the speed changes on the monitored limited-access highway network in the evening peak period.

In 2006, we expect to publish results from the 2004–2005 monitoring of the limited-access highways.