National Traffic Speeds Survey III: 2015
-
2018-03-01
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
DOI:
-
Resource Type:
-
Geographical Coverage:
-
Contracting Officer:
-
Corporate Publisher:
-
Abstract:A field survey was conducted during the summer of 2015 as a longitudinal repetition to similar efforts undertaken in 2007 and 2009. The goal was to measure travel speeds and prepare nationally representative speed estimates for all types of motor vehicles on freeways, arterial highways, and collector roads across the United States. Over 12 million vehicle speeds were measured at 677 sites included in the geographic cluster sample of 24 primary sampling units (PSUs). Each PSU was a county, or group of two or three counties representing combinations of regions of the United States, level of urbanization, and type of topography (flat, hilly, mountainous). Speeds were acquired on randomly drawn road segments on limited access highways, major and minor arterial roads, and collector roads. Speed measurement sites were selected in road segments with low, medium, or high degrees of horizontal and vertical curvature or gradient. Overall, speeds of free-flow traffic on freeways averaged 70.4 mph and were approximately 14 mph higher than on major arterials, which at 56.4 mph were in turn about 7 mph higher than the mean speed of 49.7 mph on minor arterials and collector roads. Most traffic exceeded the speed limits. Sixty-eight percent of traffic on limited access roads, about 56 percent of traffic on arterials, and about 58 percent of traffic on collectors exceeded the speed limit. About 16- to 19 percent of traffic exceeded the speed limit by 10 mph or more on freeways, arterials, and collector roads. While speeds of most vehicle size classes remained constant since 2009, the longest truck class (80-100 ft.) showed a 2 mph increase on limited access highways.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type: