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2021 National List of Major Freight Highway Bottlenecks and Congested Corridors
Federal Highway Administration (FHWA) Freight Mobility Trends: Truck Hours of Delay

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The following table lists the top Interstate bottlenecks and congested corridors in the U.S. based on Annual Truck Hours of Delay per Mile from 2021. The U.S. Federal Highway Administration (FHWA) used the Freight Mobility Trends tool with data from the National Performance Management Research Data Set (NPMRDS) to develop the list (https://npmrds.ritis.org).

Annual Truck Hours of Delay per Mile is calculated for each Interstate segment using the 2021 NPMRDS travel time data as follows:

  • Delay is calculated for each 15-minute time period as the difference between actual travel time and reference travel time. Reference travel time is based on 85th percentile speed during off-peak and overnight time periods.
  • Delay for each 15-minute time period is multiplied by 15-minute truck volumes. Truck volumes are estimated from annual average daily truck traffic (AADTT) using typical time-of-day traffic volume profiles. Delay for each 15-minute time period is aggregated to get annual truck hours of delay.
  • The total number of truck hours of delay is then divided by the segment length to get total truck hours of delay per mile, allowing for the comparison of all roadway sections across the National Highway System.

This analysis has been conducted for 2017 through 2021 to compare trends in congestion and delay. The use of delay per mile for assessing bottlenecks is a consistent measure that allows for comparing performance over the entire Interstate system from year to year and across all States. Annual truck hours of delay are quantified along corridors, as opposed to individual points, to consider the full delay that a truck would experience driving along a congested corridor.

The segment data for annual truck hours of delay were used as a starting point and validated against other data sources. The top bottleneck locations were compared with the bottlenecks identified by States in their State Freight Plan and 2018 and 2020 Transportation Performance Management Performance Reports. Finally, the FHWA Office of Operations’ Office of Freight Management and Operations coordinated the locations with the FHWA Division Offices and State Departments of Transportation (DOTs) for review and comment.

A new metric added to the bottleneck table is total annual metric tons of carbon dioxide (CO2) emission generated from trucks per mile of bottleneck roadway along bottleneck segment.

Table 1 lists the route, urban area, and State ranked by 2021 truck hours of delay per mile.

  • Most congested bottleneck segment: Annual truck hours of delay per mile is determined at the most congested segment of the corridor. Delay will be lower along other segments of the corridor. Information is provided for AADTT, annual truck hours of delay, planning time index (PTI), buffer index (BI), travel time index (TTI), travel reliability index (TRI), and metric tons (MT) of CO2 emissions per mile from trucks for the most congested segment of the corridor.
  • Full congested corridor: Limits of congested corridor, corridor length, and total corridor congestion cost are calculated for the full extent of delay along the congested corridor, which may include multiple bottleneck segments.

Table 1. National List of Major Freight Highway Bottlenecks and Congested Corridors
Based on Truck Hours of Delay per Mile, 2021 National Performance Management Research Data Set
2021
Rank
2020
Rank
Road
Urban Area, State
Limits of Congested
Corridor
Corridor Length
(Miles)
AADTT
(Trucks)
Delay
(Hours)
Delay/
Mile
Change
From
2020
Change
From
2019
PTI
BI
TTI
TRI
CO2/
Mile
(MT)
Total
Congestion Cost
of Full Corridor
($/year)
1
1
 I–95/ I–295 New York-Newark, NY-NJ-CT US-46 in NJ to I–278/I–678
in NY
12
26,626
2,182,899
340,120
86%
29%
11.98
271.4
3.86
2.11
87
$159,883,554
2
2
 I–90/ I–94 Chicago, IL-IN I–94N to I–55
10.5
16,052
1,140,838
123,947
79%
-12%
8.13
172.2
2.97
2.38
57
$63,058,035
3
27
 I–71/ I–75 Cincinnati, OH-KY- IN I–275 in KY to Western Hills in OH
9.2
21,302
543,489
109,555
286%
146%
5.44
130.6
2.25
1.41
48
$30,037,300
4
3
 I–278 New York-Newark, NY-NJ-CT I–95/I–678 to Grand Central Pkwy. and
SR-27 Prospect Expy. to SR-29 Queens Blvd.
7.7

9.2
19,650
2,703,702
106,846
58%
21%
7.62
199.9
2.71
2.38
61
$149,451,493
5
23
 I–80 San Francisco- Oakland, CA US-101 to Bay Bridge and at I–580
10.7
15,758
717,622
105,254
254%
106%
8.09
215.6
2.5
1.78
46
$39,665,893
6
4
 I–678 New York-Newark, NY-NJ-CT I–495 to Belt Parkway and
I–295/I–95 to south end Bronx-Whitestone Bridge
5.8

2.9
13,550
480,092
101,075
50%
1%
7.1
175.1
2.59
2.33
43
$26,538,634
7
15
 I–10 Baton Rouge, LA I–110 to SR-1
2.2
22,378
647,215
90,002
143%
56%
6.43
257.5
1.8
2.54
53
$35,771,085
8
31
 I–80/ I–94 Chicago, IL-IN I–294 to I–94
4.8
49,806
963,494
82,968
200%
28%
3.05
126.2
1.43
2.57
89
$53,248,838
9
-
 I–69C McAllen, TX At I–2
2.7
17,046
236,951
78,304
133%
119%
4.45
136.8
1.83
2.05
44
$13,093,864
10
6
 I–87 New York-Newark, NY-NJ-CT I–278 to 230th St.
5.9
11,502
408,332
77,972
76%
20%
7.39
216.7
2.34
1.78
36
$22,570,472
11
5
 I–495 New York-Newark, NY-NJ-CT Little Neck Parkway to Queens Midtown Tunnel
14.3
20,124
1,597,202
76,833
66%
8%
5.69
177.6
2.13
1.82
56
$88,287,636
12
11
 I–45 Houston, TX US-90 to I–69
4.2
18,374
593,798
73,569
85%
-13%
4.73
131.5
2.02
1.63
51
$32,817,007
13
8
 I–35 Waco, TX At 5th St.
1.4
29,552
630,635
72,581
68%
13%
4.64
193.6
1.57
2.86
58
$34,852,255
14
35
 I–710 Los Angeles-Long Beach-Anaheim, CA Cesar Chavez Ave. to Atlantic Blvd.
3
17,386
378,710
70,329
176%
-18%
6.2
231.7
1.77
2.9
45
$20,931,647
15
10
 I–10 Los Angeles-Long Beach-Anaheim, CA 20th Street to I–5 and
at I–605
15.3

6.0
16,674
1,385,645
68,351
66%
-21%
7.6
240.8
2.23
2.63
42
$76,583,680
16
7
 I–75 Chattanooga, TN- GA At I–24
1.6
23,078
102,909
66,083
50%
62%
4.39
150.8
1.71
1.53
45
$5,687,739
17
17
 I–5 Los Angeles-Long Beach-Anaheim, CA SR-134 Ventura Fwy. to I– 605
19.8
16,674
1,320,114
63,774
85%
-7%
5.75
199.4
1.92
1.88
42
$72,966,141
18
16
 I–290 Chicago, IL-IN I–90/I–94 to I–294
13.5
14,894
617,075
62,566
79%
-34%
4.61
155.9
1.8
1.95
36
$34,107,314
19
9
 I–35 Austin, TX US 290 N to Ben White Blvd./SH 71
7.9
18,820
454,504
62,363
49%
-44%
5.97
190.9
2.05
1.73
32
$25,120,597
20
38
 I–5 Seattle, WA I–90 to 85th St. and
SR-18 to Port of Tacoma Rd.
9.6

7.1
14,582
882,485
62,041
147%
-11%
5.74
216
1.99
2.54
37
$48,774,259
21
12
 I–610 Houston, TX I–69 to I–10 and
at I–45
4.1

2.1
15,452
379,358
61,566
60%
-41%
5.71
210
1.93
2.49
42
$20,967,423
22
24
 I–75/ I–85 Atlanta, GA I–20 to I–75/I–85 split
4.2
14,710
326,884
61,019
109%
-4%
5.93
166.4
2.22
1.82
39
$18,068,079
23
36
 I–285 Atlanta, GA East/ SR-400 to US-78 and
West/ I–20 to Northside Dr.
11.7

11.2
23,710
1,203,300
59,712
137%
11%
3.71
139.1
1.55
2.39
50
$66,501,658
24
-
 I–40/ I–55 Memphis, TN-MS- AR Between I–40 and I–55 split exits 279 and 277 in AR
2.7
29,118
158,998
59,510
661%
2309%
5.22
231.5
1.56
4.64
44
$8,786,757
25
22
 I–69/ US-59 Houston, TX SR-527 to I 10
4.4
13,774
350,962
58,407
95%
-35%
7.07
251.2
2.1
2.32
37
$19,396,490
26
18
 I–405 Los Angeles-Long Beach-Anaheim,
CA		 At SR-73 and
SR-2 Santa Monica Blvd. to SR-42 Manchester Blvd.
2.5


7.5
15,162
1,311,450
58,005
73%
-39%
5.89
207.1
1.94
2.7
38
$72,484,527
27
54
 I–75 Cincinnati, OH-KY- IN SR-562 to SR-126
3
23,338
246,864
56,959
219%
65%
4.11
141.8
1.52
2.27
46
$13,644,113
28
39
 I–105 Los Angeles-Long Beach-Anaheim, CA I–405 to Long Beach Blvd.
13.7
16,674
767,698
55,564
122%
-14%
6.78
270.3
1.8
4.63
42
$42,429,278
29
-
 I–55 Memphis, TN-MS- AR

I–40 and I–55 split in AR to Crump Blvd. on TN side of Mississippi River
4.7
21,294
144,247
54,996
1555%
1709%
6.61
323.4
1.55
5.85
44
$7,972,033
30
70
 I–15 Las Vegas- Henderson, NV I–515 to Tropicana Ave.
5.5
31,010
634,588
54,634
258%
147%
3.09
118.6
1.41
1.96
59
$35,068,519
31
14
 I–24 Nashville-Davidson, TN US-41 to SR-155
5.8
26,772
474,415
53,456
42%
-38%
3.74
171.5
1.49
3.05
57
$26,221,736
32
13
 I– 35W Dallas-Fort Worth- Arlington, TX At I–30
1.2
13,818
97,911
52,554
38%
111%
4.62
121.3
2.06
1.3
29
$5,411,445
33
73
 I–93 Boston, MA-NH-RI At I–90 and
at SR-3
5.0
5.5
13,704
543,540
49,510
233%
81%
5.22
176.9
1.88
2.94
37
$30,042,839
34
29
 I–24/ I–65 Nashville-Davidson, TN I–65 to I–24
1.8
27,488
84,780
48,337
75%
50%
2.88
98.1
1.43
1.31
50
$4,685,762
35
20
 I–95 Washington, DC- VA-MD SR-123 to SR-286
6.3
17,652
595,518
46,146
41%
-6%
3.93
145
1.61
2.03
38
$32,912,098
36
53
 I–80/ I–294 Chicago, IL-IN I–94 to I–294
6.5
37,032
300,763
46,132
145%
40%
3.05
126.4
1.34
2.65
57
$16,622,028
37
64
 I–10 Houston, TX I–69 to I–45
2.1
19,098
291,811
44,603
176%
-75%
3.98
144.6
1.58
1.78
$16,128,461
38
26
 I–25 Denver-Aurora, CO I–70 to University Blvd.
8.7
24,402
350,753
43,161
52%
-23%
4.16
152
1.65
2.47
60
$19,386,789
39
52
 I–24 Chattanooga, TN- GA I–75 to US-41
3.5
39,326
610,877
42,780
125%
33%
3.95
186.6
1.38
3.58
90
$33,763,659
40
44
 I–75 Atlanta, GA I–85 to Moores Mill Rd.
3.3
16,804
261,395
42,285
95%
78%
4.85
208.3
1.57
2.5
36
$14,445,832
41
34
 I–76 Philadelphia, PA- NJ-DE-MD University Ave. to US-1
6.2
11,440
305,582
42,017
62%
-37%
5.39
188.5
1.84
2.06
33
$16,891,818
42
21
 I–270 Denver-Aurora, CO I–25 to I–70
5.8
10,750
182,009
40,436
32%
-19%
5.85
191.9
1.98
1.86
26
$10,059,745
43
32
 I–5 Portland, OR-WA Columbia River to Terwilliger Blvd.
10.5
19,440
503,062
40,407
48%
-27%
4.71
202.4
1.55
2.75
37
$27,804,513
44
49
 I–10 New Orleans, LA SR-49 to I–610 and
at Pontchartrain Expy.
7.5

3.9
39,384
412,570
39,944
102%
-35%
4.3
153.1
1.7
2.23
82
$22,800,365
45
45
 I–55 Chicago, IL-IN I–94 to SR-171
10
14,356
363,710
38,433
78%
-29%
4.89
181.9
1.69
2.22
32
$20,102,458
46
-
 I–345/ US-75 Dallas-Fort Worth- Arlington, TX Woodall Rodgers Fwy. to I– 30
2
13,210
73,033
37,216
34%
5%
5.24
216.6
1.63
3.03
27
$4,036,493
47
19
 I–30 Little Rock, AR I–630 to I–40
2.9
40,520
334,023
36,188
9%
-30%
1.98
56
1.21
1.74
86
$18,461,092
48
48
 I–95 Philadelphia, PA- NJ-DE-MD At I–676
1.7
26,644
60,526
35,778
77%
0%
3.42
157.8
1.33
3.07
66
$3,345,131
49
47
 I–635 Dallas-Fort Worth- Arlington, TX I–35 to SR-78
14
18,302
624,526
35,693
73%
-4%
3.8
137
1.6
2.1
39
$34,515,016
50
40
 I–676 Philadelphia, PA- NJ-DE-MD I–76 to I–95
2.2
8,760
135,423
35,595
47%
-12%
4.69
142.4
2.03
1.64
26
$7,485,968
51
-
 I–610 New Orleans, LA At I–10
1.4
14,920
50,400
35,067
59%
-7%
4.8
220.4
1.49
3.65
39
$2,785,692
52
-
 I–515 Las Vegas- Henderson, NV I–15 to Flamingo Rd.
7.1
18,342
281,575
34,631
367%
171%
4.3
132.6
1.79
1.56
34
$15,561,856
53
63
 I–15 Los Angeles-Long Beach-Anaheim,
CA		 At I–10
3.2
16,674
174,824
34,480
106%
-28%
3.07
114.1
1.42
2
38
$9,662,995
54
30
 I–70 Denver-Aurora, CO I–25 to I–270
4.8
16,580
144,385
34,127
23%
-36%
3.97
141.9
1.64
1.79
36
$7,980,896
55
71
 I–294 Chicago, IL-IN At I–290; and
at I–90
6.1

3.9
31,888
351,488
33,250
118%
-21%
3.06
131.9
1.31
2.39
59
$19,426,409
56
28
 I–30 Dallas-Fort Worth- Arlington, TX I–35 to Grand Ave.
4
15,156
297,056
33,199
20%
6%
4.28
157.2
1.65
1.94
26
$16,418,607
57
33
 I–95 Bridgeport- Stamford, CT-NY At US-1 in Fairfield and
at US-1 in Stamford
1.5

1.8
20,496
1,116,502
32,554
22%
19%
3.48
139.3
1.46
2.22
46
$61,708,615
58
55
 I–95 New Haven, CT I–91 to SR-10
1.8
15,794
58,948
32,277
82%
20%
3.92
172.6
1.43
2.98
32
$3,258,121
59
61
 I–15 Riverside-San Bernardino, CA At SR-91
2.2
11,350
113,529
32,247
92%
-33%
6.66
245.2
2.05
3.73
30
$6,274,869
60
I–15 Ogden-Layton, UT I–84 to 650 N
4
24,584
172,848
32,081
101%
33%
3.38
155.6
1.32
2.85
58
$9,552,901
61
86
 I–90 Chicago, IL-IN I–90/94 to I–294
6.7
22,800
352,554
31,695
166%
-27%
6.29
160.3
2.42
2.5
40
$19,483,539
62
65
 I–110 Los Angeles-Long Beach-Anaheim, CA I–10 to SR-42 Stauson Ave.
3.4
11,556
96,545
31,370
94%
-36%
4.86
158.3
1.86
2.04
25
$5,336,276
63
90
 I–64 St. Louis, MO-IL Market St. to I–70 (over Mississippi River)
5
10,130
41,181
30,634
170%
-28%
3.47
129.8
1.42
2.94
30
$2,275,952
64
58
 I–880 San Francisco- Oakland, CA SR-92 to SR-84
6.4
16,524
268,839
30,103
75%
-9%
3.02
109.3
1.43
1.62
38
$14,858,141
65
I–45 Dallas-Fort Worth- Arlington, TX Illinois Ave to Wright Fwy.
3.4
16,680
101,570
29,874
206%
89%
2.93
89.6
1.42
1.47
36
$5,613,271
66
51
 I–695 Baltimore, MD I–95 to I–795
10.1
19,174
31,097
29,491
53%
-36%
2.73
110.4
1.3
2.11
48
$1,718,878
67
46
 I–605 Los Angeles-Long Beach-Anaheim, CA I–5 to SR-60
6.5
16,024
179,208
29,179
38%
-79%
3.27
94.4
1.68
1.43
34
$9,905,503
68
69
 I–215 Riverside-San Bernardino, CA I–10 to SR-80
5.9
14,384
435,697
28,811
88%
-18%
2.92
79.5
1.54
1.28
31
$24,083,078
69
41
 I–35E Dallas-Fort Worth- Arlington, TX I–30 to John W. Carpenter/SH 183
2.8
17,298
117,682
28,780
23%
-23%
3.02
111.3
1.42
1.69
35
$6,505,010
70
68
 I–210 Los Angeles-Long Beach-Anaheim, CA SR-39/164 Azusa Ave. to SR-19 Rosemead Blvd
10
19,966
255,762
28,244
80%
-53%
2.87
116.3
1.36
1.8
44
$14,136,524
71
74
 I–580 Concord, CA At I–680
1.1
16,674
30,924
28,133
96%
-42%
3.66
166.8
1.37
3.01
35
$1,709,154
72
43
 I–94 Chicago, IL-IN I–90/94 to US-14
2.3
16,000
91,783
27,301
23%
-19%
3.03
117.7
1.39
1.63
33
$5,072,824
73
50
 I–405 Seattle, WA I–90 to SR-520
3.7
10,364
121,276
27,213
40%
-33%
4.35
171.6
1.56
2.27
27
$6,702,947
74
62
 I–85 Atlanta, GA I–75 to SR 13/141 and
I–285 to SR-378
2.8

6.6
23,884
322,228
27,192
63%
-28%
5.32
169.4
1.96
1.8
50
$17,807,833
75
79
 I–580 San Francisco- Oakland, CA At I–980 and at US-101
1.4
16,674
37,888
26,717
106%
-31%
3.07
100.5
1.47
1.6
36
$2,093,729
76
80
 I–10 Riverside-San Bernardino, CA At I–215
8.5
20,308
223,143
26,329
345%
-16%
2.35
80.4
1.27
1.64
45
$12,333,853
77
66
 I–24/ I–40 Nashville-Davidson, TN I–24 to I–65
3.0
12,032
42,086
25,217
57%
-26%
3.11
111.9
1.46
1.48
25
$2,326,247
78
79
 I–40 Memphis, TN-MS- AR At I–55
2.8
19,464
71,443
24,961
95%
911%
1.9
33.2
1.4
1.77
26
$3,948,148
79
I–70 Rural, IN SR-9 to N 600 W
9.6
18,104
231,819
24,229
608%
276%
3.51
138
1.46
1.61
35
$12,813,635
80
98
 I–20 Dallas-Fort Worth- Arlington, TX At SR-360
5.8
26,572
139,885
24,095
123%
106%
1.97
56.6
1.22
1.39
50
$7,730,484
81
88
 I–40 Knoxville, TN At I–140
2.3
20,680
54,804
24,063
108%
20%
2.64
108.7
1.25
2.24
37
$3,028,903
82
-
 I–110 El Paso, TX-NM I–10 to Mexican border
0.7
2,168
16,422
23,785
166%
379%
11.22
130.8
4.8
1.24
5
$907,489
83
-
 I–205 Rural, CA At I–580
4.0
13,870
89,660
23,343
31%
-43%
4.24
197
1.43
3.04
29
$4,955,402
84
-
 I–630 Little Rock, AR At I–30
0.7
33,186
15,886
23,312
127%
-3%
1.8
46.6
1.22
1.37
55
$877,947
85
37
 I–495 Washington, DC- VA-MD I–66 (VA) to I–95 (MD)
19.5
8644
83,856
23,167
264%
72%
2.39
90
1.25
1.84
38.42
$5,515,292
86
-
 I–74/ I–465 Indianapolis, IN I–65 to SR-37
4.3
20,244
99,783
23,167
264%
72%
2.39
89.9
1.25
1.84
38
$5,515,292
87
75
 I–12 Baton Rouge, LA At I–10
3.1
19,292
72,240
23,108
62%
-2%
2.07
65.9
1.24
1.88
43
$3,992,476
88
59
 I–10 Lake Charles, LA At I–210
9.3
29,982
208,203
22,434
31%
-63%
1.57
32.8
1.17
1.4
59
$11,506,626
89
77
 I–20 Atlanta, GA I–285 to SR-6
6.0
11,800
133,215
22,379
73%
16%
2.98
108.7
1.43
1.69
28
$7,363,013
90
78
 I–820 Dallas-Fort Worth- Arlington, TX At I–35W
3.0
8,596
66,133
22,237
72%
379%
3.61
98.5
1.68
1.37
22
$3,655,498
91
76
 I–376 Pittsburgh, PA Fort Pitt Bridge to Squirrel Hill
4.5
5,156
35,777
22,195
58%
-29%
5.19
211.7
1.67
2.7
17
$1,977,539
92
60
 I–95 Aberdeen-Bel Air
South-Bel Air North, MD		 SR 24 to SR 152
1.6
23,414
35,629
21,597
28%
-40%
2.76
117.5
1.27
2.31
52
$1,969,047
93
-
 I–55 St. Louis, MO-IL I–44 and I–64
1.5
17,276
33,118
21,408
264%
83%
2.72
106.6
1.29
2.09
29
$1,830,424
94
-
 I–287 New York-Newark, NY-NJ-CT I–87 to SR-100
2.5
20,914
52,564
21,385
90%
-32%
2.03
62.5
1.23
1.26
40
$2,905,230
95
-
 I–35 San Antonio, TX At I–10
4.4
24,856
92,582
21,195
111%
-46%
2.22
79.6
1.22
1.6
56
$5,116,612
96
-
 I–65 Nashville, TN At SR-386
2.6
13,768
53,488
20,874
84%
4%
3.44
156
1.33
2.75
25
$2,955,977
97
-
 I–5 San Diego, CA Via de la Valle to Encinitas Blvd
5.2
16,674
105,443
20,351
2.69
108
1.29
2.05
37
$31,211,000
98
-
 I–4 Tampa, FL East of I–275
5.8
13,750
110,354
19,103
68%
-12%
1.36
61
2.32
1.32
29
$16,630,000
99
-
 I–95 Miami, FL Florida Turnpike to I–395
7.7
4,816
147,218
19,018
72%
-13%
3.90
146
1.58
2.00
20
$8,136,264
100
-
 I–94 Milwaukee, WI At I–41/I–894
2.9
7,004
43,760
15,219
75%
-19%
2.6
102
1.27
2.03
29
$2,418,631

AADTT = average daily truck traffic; BI = buffer index; PTI = planning time index; TRI = travel reliability index; TTI = travel time index.

Information is provided in the table for the overall congested corridor, bottleneck segment with the greatest delay, and congestion costs for all congested segments with the urbanized area.

  • Limits of Congested Corridor and Corridor Length: The extent of congestion of the primary bottleneck on the corridor is estimated based on review of corridor congestion scans in the NPMRDS and review of State Freight Plans. For major congested corridors, the described limits of the congested corridor may include multiple contiguous bottlenecks. For corridors with multiple distinct bottleneck locations, two corridors will be noted. These locations have been further refined based on review of 2021 NPMRDS data and State 2020 Performance Reports.
  • Bottleneck Segment with Greatest Delay: The following information is provided for the segment along the corridor with the greatest truck hours of delay per mile:
    • AADTT (Trucks): NPMRDS total of single-unit and combination trucks conflated from Highway Performance Monitoring System (HPMS). Note, the prior year HPMS data are conflated to the NPMRDS at the beginning of each year. Therefore, the 2021 NPMRDS shows traffic counts taken in 2018.
    • Delay per mile: Annual truck hours of delay determined as the difference between actual travel time and reference travel time (“free-flow” travel time), multiplied by truck volumes for the segment with the greatest delay. Annual truck hours of delay is divided by the segment length to provide the delay per mile. For larger bottlenecks that span multiple roadway segments, delay is provided for the most congested segment and direction of the bottleneck, not the full corridor.
    • Change from 2020: The percent change in annual truck hours of delay per mile from 2020 to 2021.
    • Change from 2019: The percent change in annual truck hours of delay per mile from 2019 to 2021 is provided for a comparison to pre-COVID-19 global pandemic traffic conditions.
    • PTI: Ratio of the 95th percentile travel time to the reference travel time (“free-flow” travel time), computed during the AM and PM peak periods.
    • BI: Represents the extra time (or time cushion) that travelers must add to their average travel time when planning trips to ensure on-time arrival.
    • TTI: Ratio of the peak-period travel time to the reference travel time (“free-flow” travel time), computed for the AM and PM peak periods.
    • TRI: Ratio of the 95th percentile travel time to the 50th percentile travel time during five different time periods of the day. Calculated similar to the Moving Ahead for Progress in the 21st Century Act (MAP-21) (Pub. L. No. 112-141) performance measure for truck travel time reliability (TTTR); however, results will differ from the NPMRDS TTTR due to differences in route segmentation.
    • CO2 per Mile: Total annual metric tons of CO2 generated from trucks per mile of bottleneck roadway along segment.
  • Total Congestion Cost of Full Corridor ($/year): Calculated for the full extent of delay along the congested corridor as a function of both the time and fuel used while the truck is in congested traffic, factoring costs of personnel, commercial vehicle operation, and wasted fuel. For major bottlenecks with long congestion queues, the full corridor will include multiple roadway segments. For major congested corridors, the congestion cost will include the full cost of congestion along the corridor through the entire urban area, which may include multiple bottlenecks. The congestion cost may include delay at other congested segments beyond the primary bottleneck in the urban area.

Changes Between 2020 and 2021

There was an overall increase in delay for nearly all bottlenecks as traffic volumes began to resume after the 2020 COVID-19 global pandemic stay-at-home orders. Nationwide, there was a reduction in total truck delay on the Interstate system of 41 percent between 2019 and 2020 followed by an increase in 2021. Total truck delay on the Interstate system in 2021 returned to 84 percent of 2019 pre- COVID-19 global pandemic delay.

Although there was a large increase in delay for nearly all bottlenecks, the following bottlenecks saw the greatest relative percent increase in delay between 2020 and 2021. Major roadwork was another source of increased delay on certain routes. As table 2 shows, the emergency closure of the I–40 Hernando DeSoto Bridge over the Mississippi River caused the largest increase in delay on I–55 and other roadways in the Memphis, TN-AR area.

Table 2. Greatest Increase in Delay Between 2020 and 2021
Road
Urban Area, State
Percent Increase in Delay
Per Mile From 2020
I–55 Memphis, TN-MS-AR
1555%
I–40/ I–55 Memphis, TN-MS-AR
661%
I–70 Rural, IN
608%
I–515 Las Vegas-Henderson, NV
367%
I–580 San Francisco-Oakland, CA
363%
I–71/ I–75 Cincinnati, OH-KY-IN
286%
I–74/ I–465 Indianapolis, IN
264%
I–55 St. Louis, MO-IL
264%
I–15 Las Vegas-Henderson, NV
258%
I–80 San Francisco-Oakland, CA
254%

Based on changes to truck hours of delay per mile, the following bottlenecks saw a relative increase in delay, moving the locations to the top 100 bottlenecks, or a relative decrease in delay, dropping the locations below the top 100 bottlenecks.

The following bottlenecks were added to the list in 2021:

Table 3. Locations Added to Top 100
Between 2020 and 2021
Road
Urban Area, State
I–55 Memphis, TN-MS-AR
I–40/ I–55 Memphis, TN-MS-AR
I–70 Rural, IN
I–515 Las Vegas-Henderson, NV
I–74/ I–465 Indianapolis, IN
I–55 St. Louis, MO-IL
I–45 Dallas-Fort Worth-Arlington, TX
I–110 El Paso, TX-NM
I–69C McAllen, TX
I–630 Little Rock, AR
I–35 San Antonio, TX
I–15 Ogden-Layton, UT
I–287 New York-Newark, NY-NJ-CT
I–610 New Orleans, LA
I–345/ US-75 Dallas-Fort Worth-Arlington, TX
I–205 Rural, CA
I–5 San Diego, CA
I–4 Tampa-St. Petersburg, FL
I–94 Milwaukee, WI

 

The following bottlenecks from 2020 dropped off the list in 2021:

Table 4 Locations Removed From Top 100
Between 2020 and 2021
Road Urban Area, State
I–680 San Francisco-Oakland, CA
I–580 Livermore, CA
I–435 Kansas City, MO-KS
I–15 Salt Lake City, UT
I–95 Washington, DC-MD-VA
I–78 New York-Newark, NY-NJ
I–84 Waterbury, CT
I–39 Rockford IL
I–70 St. Louis, MO
I–270 St. Louis, MO
I–4 Orlando, FL
I–270 Washington, DC-MD-VA
I–225 Denver-Aurora, CO
I–95 Fredericksburg, VA
I–295 New York-Newark, NY-NJ-CT
I–80/ Chicago, IL-IN
I–35 Kansas City, MO-KS
I–15 Murrieta-Temecula-Menifee, CA
I–75 Toledo, OH

 

Mapped Locations

Figure 1 shows the top Interstate bottlenecks in the United States as listed in table 1 based on Annual Truck Hours of Delay per Mile for 2021.

 

Map showing the location of the 2021 top 100 major Interstate freight bottlenecks ranked by Truck Hours of Delay per Mile as listed in table 1

Figure 1. Map. Major Interstate Highway Freight Bottlenecks Based on Annual Truck Hours of Delay per Mile, 2021 National Performance
Management Research Data Set

Map showing the location of the 2021 top 100 major Interstate freight bottlenecks ranked by Truck Hours of Delay per Mile as listed in table 1: I-95/ I-295 New York-Newark, NY-NJ-CT, I-90/ I-94 Chicago, IL-IN, I-71/ I-75 Cincinnati, OH-KY-IN, I-278 New York-Newark, NY-NJ-CT, I-80 San Francisco-Oakland, CA, I-678 New York-Newark, NY-NJ-CT, I-10 Baton Rouge, LA, I-80/ I-94 Chicago, IL-IN, I-69C McAllen, TX, I-87 New York-Newark, NY-NJ-CT, I-495 New York-Newark, NY-NJ-CT, I-45 Houston, TX, I-35 Waco, TX, I-710 Los Angeles-Long Beach-Anaheim, CA, I-10 Los Angeles-Long Beach-Anaheim, CA, I-75 Chattanooga, TN-GA, I-5 Los Angeles-Long Beach-Anaheim, CA, I-290 Chicago, IL-IN, I-35 Austin, TX, I-5 Seattle, WA, I-610 Houston, TX, I-75/ I-85 Atlanta, GA, I-285 Atlanta, GA, I-40/ I-55 Memphis, TN-MS-AR, I-69/ US-59 Houston, TX, I-405 Los Angeles-Long Beach-Anaheim, CA, I-75 Cincinnati, OH-KY-IN, I-105 Los Angeles-Long Beach-Anaheim, CA, I-55 Memphis, TN-MS-AR, I-15 Las Vegas-Henderson, NV, I-24 Nashville-Davidson, TN, I-35W Dallas-Fort Worth-Arlington, TX, I-93 Boston, MA-NH-RI, I-24/ I-65 Nashville-Davidson, TN, I-95 Washington, DC-VA-MD, I-80/ I-294 Chicago, IL-IN, I-10 Houston, TX, I-25 Denver-Aurora, CO, I-24 Chattanooga, TN-GA, I-75 Atlanta, GA, I-76 Philadelphia, PA-NJ-DE-MD, I-270 Denver-Aurora, CO, I-5 Portland, OR-WA, I-10 New Orleans, LA, I-55 Chicago, IL-IN, I-345/ US-75 Dallas-Fort Worth-Arlington, TX, I-30 Little Rock, AR, I-95 Philadelphia, PA-NJ-DE-MD, I-635 Dallas-Fort Worth-Arlington, TX, I-676 Philadelphia, PA-NJ-DE-MD, I-610 New Orleans, LA, I-515 Las Vegas-Henderson, NV, I-15 Los Angeles-Long Beach-Anaheim, CA, I-70 Denver-Aurora, CO, I-294 Chicago, IL-IN, I-30 Dallas-Fort Worth-Arlington, TX, I-95 Bridgeport-Stamford, CT-NY, I-95 New Haven, CT, I-15 Riverside-San Bernardino, CA, I-15 Ogden-Layton, UT, I-90 Chicago, IL-IN, I-110 Los Angeles-Long Beach-Anaheim, CA, I-64 St. Louis, MO-IL, I-880 San Francisco-Oakland, CA, I-45 Dallas-Fort Worth-Arlington, TX, I-695 Baltimore, MD, I-605 Los Angeles-Long Beach-Anaheim, CA, I-215 Riverside-San Bernardino, CA, I-35E Dallas-Fort Worth-Arlington, TX, I-210 Los Angeles-Long Beach-Anaheim, CA, I-580 Concord, CA, I-94 Chicago, IL-IN, I-405 Seattle, WA, I-85 Atlanta, GA, I-580 San Francisco-Oakland, CA, I-10 Riverside-San Bernardino, CA, I-24/ I-40 Nashville-Davidson, TN, I-40 Memphis, TN-MS-AR, I-70 Rural, IN, I-20 Dallas-Fort Worth-Arlington, TX, I-40 Knoxville, TN, I-110 El Paso, TX-NM, I-205 Rural, CA, I-630 Little Rock, AR, I-495 Washington, DC-VA-MD, I-74/ I-465 Indianapolis, IN, I-12 Baton Rouge, LA, I-10 Lake Charles, LA, I-20 Atlanta, GA, I-820 Dallas-Fort Worth-Arlington, TX, I-376 Pittsburgh, PA, I-95 Aberdeen-Bel Air South-Bel Air North, MD, I-55 St. Louis, MO-IL, I-287 New York-Newark, NY-NJ-CT, I-35 San Antonio, TX, I-65 Nashville, TN, I-5 San Diego, CA, I-4 Tampa, FL, I-95 Miami, FL, I-94 Milwaukee, WI.

Other Bottlenecks

The analysis in this report uses delay per mile for assessing bottlenecks to allow for comparison over the entire Interstate system across all States. Individual State DOTs and metropolitan planning organizations use a range of bottleneck identification methods based on their freight plan development process and local traffic characteristics, infrastructure constraints, and impediments to efficient freight movement.

There is a range of methods for measuring congestion, delay, and reliability. Reliability is another factor that is important to the freight industry and can be measured with metrics such as the TTTR or some of the other indices listed in table 1.

In addition to congestion-based delay, some truck freight bottlenecks can be attributed to infrastructure restrictions that uniquely impact trucks, such as bridges with weight or clearance restrictions; steep grades; frequent adverse weather; or constraints at facilities, such as ports, intermodal rail facilities, and border crossings.

Individual State Freight Plans should be reviewed for additional information on the various types of freight bottlenecks.

Disclaimer

Except for the statutes and regulations cited, the contents of this document do not have the force and effect of law and are not meant to bind the States or the public in any way. This document is intended only to provide information regarding existing requirements under the law or agency policies.
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