(Miles)
| Unknown | 1963-1989 | 1990 | 1991 | (R) 1,992 | (R) 1,993 | (R) 1,994 | (R) 1,995 | 1996 | (R) 1,997 | (R) 1,998 | 1999 | (R) 2,000 | (R) 2,001 | (R) 2,002 | (R) 2,003 | (R) 2,004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | Total 1963-2010 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TOTAL length | 6 | 736 | 64 | 99 | 142 | 84 | 88 | 127 | 54 | 101 | 144 | 54 | 83 | 114 | 96 | 92 | 129 | 89 | 118 | 105 | 49 | 87 | 95 | 2,748 |
| Type I barriersa | d6 | 507 | 44 | 78 | 113 | 63 | 48 | 93 | 37 | 67 | 119 | 31 | 67 | 72 | 59 | 76 | 99 | 56 | 80 | 57 | 38 | 63 | 70 | 1,938 |
| Type II barriersb | 0 | 198 | 19 | 18 | 18 | 21 | 16 | 32 | 15 | 31 | 23 | 18 | 11 | 18 | 13 | 4 | 15 | 10 | 13 | 19 | 3 | 5 | 13 | 533 |
| All other typesc | N | 31 | 1 | 3 | 11 | 0 | 24 | 2 | 2 | 3 | 2 | 5 | 5 | 24 | 24 | 12 | 15 | 23 | 25 | 29 | 8 | 19 | 12 | 277 |
| Cost (2010$ millions) | 0 | 1,097 | (R) 124 | (R) 203 | 261 | 163 | 158 | 226 | (R) 92 | 202 | 290 | (R) 130 | 168 | 254 | 356 | 202 | 216 | 211 | 257 | 279 | 104 | 205 | 245 | 5,444 |
KEY: N = data do not exist; R = revised.
a A Type I barrier is built on a new highway project or a physically altered existing highway.
b A Type II barrier is built to abate noise along an existing highway (often referred to as retrofit abatement) and is not mandatory.
c All other types of barriers are nonfederally funded.
d Have not been assigned a year of construction or a cost.
NOTES
Miles of noise barriers that can neither be assigned a year of construction nor a cost.
Miles of barriers, while assigned a year of construction, cannot be assigned a cost.
SOURCE
U.S. Department of Transportation, Federal Highway Administration, Office of Environment and Planning, Highway Traffic Noise Barrier Construction Trends (Washington, DC: December 2010), tables 5 and 7, and similar tables in earlier editions available at http://www.fhwa.dot.gov/environMent/noise/barrier/summary.htm as of Nov. 12, 2012.