Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide (2024)

Chapter: 19 Case Study: Montana US-287

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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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CHAPTER 19

Case Study: Montana US-287

19.1 Route Description

This route extends from 1.0 mile south of the small rural town of Townsend to the center of East Helena, Montana. US-287 serves as an important connection between Helena and I-90. This section of US-287 is approximately 30 miles in length.

The highest posted speed limit is 70 mi/h for the rural parts of the corridor (majority distance by length) and the lowest posted speed limit is 25 mi/h in the town of Townsend. The route is shown in Figure 19.1.

19.2 LOS

Segmentation

This route mainly consists of two-lane highway segments—passing constrained, passing zones, and two stretches of passing lanes. Unlike the other case study routes, this route contains an AWSC intersection, in the town of Townsend.

The facility segmentation, in the northbound direction, for this route was performed based on the change in cross section, change in passing restrictions, and change in the posted speed limit. This resulted in a total of 38 segments, including two passing lane segments, seven segments (with different speed limits) through the town of Townsend, two signal-controlled intersections, two multilane highway segments, and one AWSC intersection in Townsend. The remaining segments are two-lane highways (with passing or no-passing restrictions).

The final segmentation is shown in Table 19.1. The total length is 30.934 mi.

Townsend is a small rural town on US Highway 287, about 32 miles southeast of Helena. The total population of Townsend is 2,080 people (according to 2020 census data). The stretch of road through the town of Townsend comprises eight segments as indicated in Table 19.2 (starting at the southeast end of the town).

The stretch of road through the town of Townsend is approximately 1.9 miles in length, as shown in Figure 19.2.

The speed limits are 45, 35, and 25 mi/h entering the town and in the reverse order exiting the town. The roadway characteristics through the town are as follows:

  • One lane in the analysis direction.
  • Two-way left-turn lane in the center.
  • AWSC intersection.
  • No curb or gutter at the beginning of town, and then curb on both sides (starts at E-street).
Page 257
Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Montana US-287 study route boundaries
Source: Map data from [©OpenStreetMap](https://www.openstreetmap.org/copyright).

Figure 19.1. Montana US-287 study route boundaries.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Table 19.1. Final segmentation for Montana US-287 study route.

Segment ID Hwy Segment Type Two-Lane Segment Type # Directional Lanes Length (ft) Grade (%) Vertical Align Class # Horizontal Curves Posted Speed (mi/h)
1 Two-Lane Highway PassingConstrained 1 1,515 <2 1 R>3,000 ft 70
2 Two-Lane Highway PassingZone 1 2,670 <2 1 R>3,000 ft 55
3 Two-Lane Highway PassingConstrained 1 530 <2 1 R>3,000 ft 55
4 Two-Lane Highway PassingConstrained 1 530 <2 1 R>3,000 ft 45
5 Two-Lane Highway PassingConstrained 1 2,650 <2 1 R>3,000 ft 45
6 Two-Lane Highway PassingConstrained 1 1,580 <2 1 R>3,000 ft 35
7 Two-Lane Highway PassingConstrained 1 530 <2 1 R>3,000 ft 25
8 AWSC NA 1 85 <2 1 R>3,000 ft 25
9 Two-Lane Highway PassingConstrained 1 965 <2 1 R>3,000 ft 25
10 Two-Lane Highway PassingConstrained 1 1,580 <2 1 R>3,000 ft 35
11 Two-Lane Highway PassingConstrained 1 2,100 <2 1 R>3,000 ft 45
12 Two-Lane Highway PassingConstrained 1 3,170 <2 1 R>3,000 ft 55
13 Two-Lane Highway PassingZone 1 5,500 <2 1 R>3,000 ft 70
14 Two-Lane Highway PassingConstrained 1 3,700 <2 1 R>3,000 ft 70
15 Two-Lane Highway PassingZone 1 9,500 <2 1 R>3,000 ft 70
16 Two-Lane Highway PassingConstrained 1 4,225 <2 1 R>3,000 ft 70
17 Two-Lane Highway PassingZone 1 5,280 <2 1 R>3,000 ft 70
18 Two-Lane Highway PassingLane 2 12,670 <2 1 R>3,000 ft 70
19 Two-Lane Highway PassingConstrained 1 1,056 <2 1 R>3,000 ft 70
20 Two-Lane Highway PassingZone 1 13,730 <2 1 R>3,000 ft 70
21 Two-Lane Highway PassingConstrained 1 4,225 <2 1 R>3,000 ft 70
22 Two-Lane Highway PassingZone 1 4,225 <2 1 R>3,000 ft 55
23 Two-Lane Highway PassingConstrained 1 3,170 <2 1 R>3,000 ft 70
24 Two-Lane Highway PassingZone 1 13,728 <2 1 R>3,000 ft 70
25 Two-Lane Highway PassingConstrained 1 4,750 <2 1 R>3,000 ft 70
26 Two-Lane Highway PassingLane 2 7,400 <2 1 R>3,000 ft 55
27 Two-Lane Highway PassingConstrained 1 3,700 <2 1 R>3,000 ft 70
28 Two-Lane Highway PassingZone 1 4,750 <2 1 R>3,000 ft 70
29 Two-Lane Highway PassingConstrained 1 1,590 <2 1 R>3,000 ft 70
30 Two-Lane Highway PassingZone 1 2,100 <2 1 R>3,000 ft 55
31 Two-Lane Highway PassingConstrained 1 3,170 <2 1 R>3,000 ft 70
32 Two-Lane Highway PassingZone 1 19,536 <2 1 R>3,000 ft 70
33 Two-Lane Highway PassingConstrained 1 4,752 <2 1 R>3,000 ft 40
34 Two-Lane Highway PassingConstrained 1 5,800 <2 1 R>3,000 ft 55
35 Signalized Intersection NA 2 120 <2 1 R>3,000 ft 45
36 Multilane Highway NA 2 3,580 <2 1 R>3,000 ft 45
37 Signalized Intersection NA 2 120 <2 1 R>3,000 ft 45
38 Multilane Highway NA 2 3,050 <2 1 R>3,000 ft 55
Page 259
Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Table 19.2. Segments through Townsend, Montana (US-287).

Segment ID Hwy Segment Type Two-Lane Segment Type # Directional Lanes Length (ft) Grade (%) Vertical Align Class Posted Speed (mi/h)
1 Two-Lane Highway PassingConstrained 1 530 0 1 45
2 Two-Lane Highway PassingConstrained 1 2,650 0 1 45
3 Two-Lane Highway PassingConstrained 1 1,580 0 1 35
4 Two-Lane Highway PassingConstrained 1 530 0 1 25
5 AWSC NA 1 85 0 1 25
6 Two-Lane Highway PassingConstrained 1 965 0 1 25
7 Two-Lane Highway PassingConstrained 1 1,580 0 1 35
8 Two-Lane Highway PassingConstrained 1 2,100 0 1 45
  • Sidewalk on the east side of the roadway only.
  • Numerous driveways and access roads within the town limits.
  • 25 mi/h zone in Townsend is about 0.32 miles (1,700 ft) long.

For the AWSC intersection (Segment 8), the upstream and downstream influence areas are initially calculated per Equation (2.5) and Equation (2.6), respectively. However, because of the low posted speed limit in this location, the practical braking and acceleration distance equations govern Equation (2.7) and Equation (2.8). For the signal-controlled intersections (Segments 35 and 37), the upstream influence area is calculated per Equation (2.1) and the downstream influence area per Equation (2.2).

The resulting influence area values are as follows:

  • Segment 8, upstream influence area = 151 ft (0.0286 mi), downstream influence area = 125 ft (0.0237 mi).
  • Segment 35, upstream influence area = 1,220 ft (0.2309 mi), downstream influence area = 1906 ft (0.2077 mi).
  • Segment 37, upstream influence area = 643 ft (0.1218 mi), downstream influence area = 1,114 ft (0.2110 mi).

Traffic Data

Traffic data were obtained from the Montana DOT (MDOT) Traffic Data Portal. Traffic sensor coverage of the area is shown in Figure 19.3.

Detector data from the study route are summarized in Table 19.3.

The assignment of volumes to segments is given in Table 19.4.

Page 260
Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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US-287 stretch through Townsend
Source: Map data ©2022 Google.

Figure 19.2. US-287 stretch through Townsend.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Traffic data sensors on US-287—Townsend route
Figure 19.3. Traffic data sensors on US-287—Townsend route.
Page 262
Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Table 19.3. US-287 Townsend route traffic data.

Sensor No. Sensor ID AADT (veh/day) K (%) D (%) Truck (%) Directional Demand (veh/h) Opposing Demand (veh/h)
1 04-1-011 4,381 11 60 10 289 193
2 04-1-010 6,863 12 60 6 494 329
3 04-1-009 7,531 11 60 6 497 331
4 04-1-008 7,169 11 60 6 473 315
5 04-1-002 6,431 11 60 7 424 283
6 W-101 6,537 12 54 7 471 314
7 A-002 7,055 11 54 6 419 357
8 25-7B-002 11,445 9 60 4 618 412
9 25-7B-024 14,013 10 63 8 883 518
10 25-7B-019 17,196 10 63 7 1,083 636

Table 19.4. Volume assignment to segment number(s) as measured from a given traffic data sensor number.

Sensor No. Corresponding Segment(s) for Volume
1 1–2
2 3–7
3 8–10
4 11–12
5 13–16
6 17–30
7 31–33
8 34–35
9 36–37
10 38

Results

The segment LOS results are shown in Tables 19.5 and 19.6.

The facility LOS results are shown in Table 19.7.

Discussion

The overall facility LOS, based on a LOS score of 1.58, is B. This is indicative of very good operations of the overall facility. This conclusion is further corroborated by an average facility speed of 65.8 mi/h and an average FFS delay of 7.8%. Further, LOS at the segment level indicates that all segments operate at LOS C or better except for three segments in the rural town of Townsend

Page 263
Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Table 19.5. US-287 segment LOS analysis results, Part 1.

Segment ID Hwy Segment Type Two-Lane Segment Type # Directional Lanes Length (mi) Effective Length Upstream (mi) Effective Length Downstream (mi) Adj. Length (mi) Posted Speed (mi/h) Directional Volume (veh/h) Opposing Volume (veh/h) PHF Directional Truck % Analysis Flow Rate (veh/h/ln) Analysis Flow Rate (pc/h/ln) Vertical Align Class Free-Flow Speed (mi/h) Free-Flow Travel Time (s) Avg Speed (mi/h) Avg Travel Time (s)
1 TwoLaneHwy PassingConstrained 1 0.2869 — — 0.2869 70 289 193 0.95 6.00 304.2 — 1 79.60 12.98 77.11 13.39
2 TwoLaneHwy PassingZone 1 0.5057 — — 0.5057 55 289 193 0.95 6.00 304.2 — 1 62.50 29.13 60.94 29.87
3 TwoLaneHwy PassingConstrained 1 0.1004 — — 0.1004 55 494 329 0.95 3.60 520.0 — 1 62.58 5.78 59.86 6.04
4 TwoLaneHwy PassingConstrained 1 0.1004 — — 0.1004 45 494 329 0.95 3.40 520.0 — 1 51.19 7.06 48.90 7.39
5 TwoLaneHwy PassingConstrained 1 0.5019 — — 0.5019 45 494 329 0.95 3.60 520.0 — 1 51.18 35.3 48.88 36.97
6 TwoLaneHwy PassingConstrained 1 0.2992 — — 0.2992 35 494 329 0.95 3.60 520.0 — 1 39.78 27.08 37.92 28.40
7 TwoLaneHwy PassingConstrained 1 0.1004 — — 0.0718 25 494 329 0.95 5.00 520.0 — 1 28.33 9.12 26.91 9.61
8 AWSCIntersection — 1 0.0161 0.0286 0.0237 0.0523 25 497 — 0.95 3.00 523.2 — — 27.50 6.84 5.72 32.92
9 TwoLaneHwy PassingConstrained 1 0.1828 — — 0.1752 25 497 331 0.95 6.00 523.2 — 1 28.30 22.29 26.87 23.47
10 TwoLaneHwy PassingConstrained 1 0.2992 — — 0.2992 35 497 331 0.95 6.00 523.2 — 1 39.70 27.13 37.84 28.47
11 TwoLaneHwy PassingConstrained 1 0.3977 — — 0.3977 45 473 315 0.95 6.00 497.9 — 1 51.10 28.02 48.86 29.30
12 TwoLaneHwy PassingConstrained 1 0.6004 — — 0.6004 55 473 315 0.95 6.00 497.9 — 1 62.50 34.58 59.83 36.13
13 TwoLaneHwy PassingZone 1 1.0417 — — 1.0417 70 424 283 0.95 4.20 446.3 — 1 79.66 47.08 76.97 48.72
14 TwoLaneHwy PassingConstrained 1 0.701 — — 0.701 70 424 283 0.95 4.20 446.3 — 1 79.66 31.68 76.54 32.97
15 TwoLaneHwy PassingZone 1 1.799 — — 1.799 70 424 283 0.95 4.20 446.3 — 1 79.66 81.3 76.95 84.17
16 TwoLaneHwy PassingConstrained 1 0.8 — — 0.8 70 424 361 0.95 4.20 446.3 — 1 79.66 36.15 76.53 37.63
17 TwoLaneHwy PassingZone 1 1 — — 1 70 471 314 0.95 4.20 495.8 — 1 79.66 45.19 76.75 46.91
18 TwoLaneHwy PassingLane 2 2.4 — — 2.4 70 471 314 0.95 4.20 495.8 — 1 79.66 108.46 79.36 108.87
18 — — Faster Lane — — — — — — — — 1.68 299.4 — — 79.70 — 80.53 107.30
18 — — Slower Lane — — — — — — — — 8.00 196.4 — — 79.50 — 77.58 111.37
19 TwoLaneHwy PassingConstrained 1 0.2 — — 0.2 70 471 314 0.95 4.20 495.8 — 1 79.66 9.04 76.38 9.43
20 TwoLaneHwy PassingZone 1 2.6 — — 2.6 70 471 314 0.95 4.20 495.8 — 1 79.66 117.5 76.72 122.00
21 TwoLaneHwy PassingConstrained 1 0.8 — — 0.8 70 471 314 0.95 4.20 495.8 — 1 79.66 36.15 76.35 37.72
22 TwoLaneHwy PassingZone 1 0.8 — — 0.8 55 471 314 0.95 4.20 495.8 — 1 62.56 46.04 60.23 47.81
23 TwoLaneHwy PassingConstrained 1 0.6 — — 0.6 70 471 314 0.95 4.20 495.8 — 1 79.66 27.12 76.36 28.29
24 TwoLaneHwy PassingZone 1 2.6 — — 2.6 70 471 314 0.95 4.20 495.8 — 1 79.66 117.5 76.72 122.00
25 TwoLaneHwy PassingConstrained 1 0.9 — — 0.9 70 471 314 0.95 4.20 495.8 — 1 79.66 40.67 76.35 42.44
26 TwoLaneHwy PassingLane 2 1.402 — — 1.402 55 471 314 0.95 4.20 495.8 — 1 62.56 80.68 62.14 81.22
26 — — Faster Lane — — — — — — — — 1.68 299.4 — — 62.60 — 63.31 79.72
26 — — Slower Lane — — — — — — — — 8.00 196.4 — — 62.40 — 60.36 83.62
27 TwoLaneHwy PassingConstrained 1 0.701 — — 0.701 70 471 314 0.95 4.20 495.8 — 1 79.66 31.68 76.36 33.05
28 TwoLaneHwy PassingZone 1 0.9 — — 0.9 70 471 314 0.95 4.20 495.8 — 1 79.66 40.67 76.75 42.21
29 TwoLaneHwy PassingConstrained 1 0.301 — — 0.301 70 471 314 0.95 4.20 495.8 — 1 79.66 13.6 76.38 14.19
30 TwoLaneHwy PassingZone 1 0.398 — — 0.398 55 471 314 0.95 4.20 495.8 — 1 62.56 22.9 60.25 23.78
31 TwoLaneHwy PassingConstrained 1 0.6 — — 0.6 70 419 357 0.95 3.60 441.1 — 1 79.68 27.11 76.58 28.21
32 TwoLaneHwy PassingZone 1 3.7 — — 3.7 70 466 357 0.95 3.60 490.5 — 1 79.68 167.17 76.73 173.59
33 TwoLaneHwy PassingConstrained 1 0.9 — — 0.9 70 466 310 0.95 3.60 490.5 — 1 79.68 40.66 76.39 42.42
34 TwoLaneHwy PassingConstrained 1 1.098 — — 0.8671 55 618 412 0.95 2.40 650.5 — 1 62.62 49.85 59.54 52.43
35 SigIntersection — 2 0.0227 0.2309 0.2077 0.4386 45 711 — 1 2.40 680.0 — — 49.50 31.9 29.79 52.99
36 MultilaneHwy — 2 0.678 — — 0.3712 45 841 — 0.95 2.00 885.3 463.9 — 52.50 25.46 52.50 25.46
37 SigIntersection — 2 0.0227 0.1218 0.211 0.3328 45 883 — 1 4.80 783.0 — — 49.50 24.2 25.69 46.62
38 MultilaneHwy — 2 0.5777 — — 0.3894 55 1080 — 0.95 2.00 1136.8 592.3 — 52.50 26.7 52.50 26.70

that were found to operate at LOS D. These three segments have a posted speed limit of 25 mi/h. Notably, the maximum d/c of 0.781 occurs at the AWSC intersection located within Townsend. The signal-controlled intersections in East Helena operate at LOS C, whereas the segments of multilane highway have densities of 8.8 veh/mi/ln and 11.3 veh/mi/ln with LOS A and B, respectively. The LOS Constancy of the facility is 0.479. This relatively low value suggests minimal variability or fluctuations in the LOS from one segment to another along the facility.

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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Table 19.6. US-287 segment LOS analysis results, Part 2.

Segment ID % Followers Density (pc/mi/ln) Density (veh/mi/ln) Follower Density (veh/mi/ln) Adj. Follower Density (veh/mi/ln) Avg. Threshold Delay (s/veh) Avg. Threshold Delay (%) Avg. Free-Flow Speed Delay (s/veh) Avg. Free-Flow Speed Delay (%) LOS LOS Value Demand/Capacity Available Capacity (veh/h) Momentum (vol x speed) Vehicle Miles Traveled Vehicle Hours Traveled Vehicle Hours of Delay
1 36.9 — 3.9 1.5 1.5 0 0 0.4 3.2 A 0.73 0.179 1,396 23,458.2 87.30 1.130 0.035
2 37.6 — 5 1.9 1.9 0 0 0.7 2.6 A 0.94 0.179 1,396 18,539.6 153.80 2.520 0.063
3 57 — 8.7 5 5 0 0 0.3 4.5 C 2.24 0.306 1,180 31,128.8 52.20 0.870 0.038
4 60.1 — 10.6 6.4 6.4 0 0 0.3 4.7 C 2.28 0.306 1,180 25,428 52.20 1.070 0.048
5 58.2 — 10.6 6.2 6.2 0 0 1.7 4.7 C 2.24 0.306 1,180 25,416.8 261.00 5.340 0.240
6 61.5 — 13.7 8.4 8.4 0 0 1.3 4.9 C 2.69 0.306 1,180 19,718.7 155.60 4.100 0.192
7 62.1 — 19.3 12 12 0 0 0.5 5.3 D 3.4 0.306 1,180 13,992.9 37.30 1.390 0.070
8 — — — — — 25.4 371.1 26.1 381.1 D 3.11 0.781 147 2,990.5 27.30 4.780 3.790
9 62.2 — 19.5 12.1 12.1 0 0 1.2 5.3 D 3.42 0.308 1,177 14,058.9 91.70 3.410 0.172
10 61.6 — 13.8 8.5 8.5 0 0 1.3 4.9 C 2.7 0.308 1,177 19,795.3 156.50 4.140 0.194
11 57.7 — 10.2 5.9 5.9 0 0 1.3 4.6 C 2.18 0.293 1,202 24,326.2 198.00 4.050 0.178
12 53.5 — 8.3 4.5 4.5 0 0 1.5 4.5 C 2.11 0.293 1,202 29,787.6 298.90 5.000 0.214
13 42.1 — 5.8 2.4 2.4 0 0 1.6 3.5 B 1.22 0.263 1,254 34,351.1 464.90 6.040 0.204
14 44 — 5.8 2.6 2.6 0 0 1.3 4.1 B 1.28 0.263 1,254 34,159.6 312.90 4.090 0.160
15 42.7 — 5.8 2.5 2.5 0 0 2.9 3.5 B 1.24 0.263 1,254 34,342.5 802.90 10.430 0.355
16 43.7 — 5.8 2.6 2.6 0 0 1.5 4.1 B 1.28 0.263 1,254 34,157.9 357.10 4.670 0.183
17 45.2 — 6.5 2.9 2.9 0 0 1.7 3.8 B 1.46 0.292 1,204 38,051.5 495.80 6.460 0.236
18 23.3 — 6.2 0.7 0.7 0 0 0.4 0.4 A 0.36 0.165 1,004 39,345.7 1,189.90 15.000 0.057
18 26.9 — 3.7 1 — — — — — — — — — — 718.59 8.924 -0.087
18 17.9 — 2.5 0.5 — — — — — — — — — — 471.31 6.075 0.149
19 49.5 — 6.5 3.2 2.6 0 0 0.4 4.3 B 1.29 0.292 1,204 37,868.3 99.20 1.300 0.053
20 46.1 — 6.5 3 2.6 0 0 4.5 3.8 B 1.31 0.292 1,204 38,038.3 1289.10 16.800 0.620
21 46.6 — 6.5 3 2.7 0 0 1.6 4.3 B 1.35 0.292 1,204 37,854.6 396.60 5.190 0.216
22 50.3 — 8.2 4.1 3.7 0 0 1.8 3.9 B 1.87 0.292 1,204 29,863.6 396.60 6.580 0.245
23 47.2 — 6.5 3.1 2.8 0 0 1.2 4.3 B 1.39 0.292 1,204 37,858.7 297.50 3.900 0.161
24 46.1 — 6.5 3 2.8 0 0 4.5 3.8 B 1.39 0.292 1,204 38,038.3 1289.10 16.800 0.620
25 46.4 — 6.5 3 2.8 0 0 1.8 4.3 B 1.42 0.292 1,204 37,852.7 446.20 5.840 0.243
26 28.4 — 8 1.1 1.1 0 0 0.5 0.7 A 0.56 0.165 1,004 30,810.7 695.10 11.190 0.074
26 32.5 — 4.7 1.5 — — — — — — — — — — 419.78 6.630 -0.071
26 22.2 — 3.3 0.7 — — — — — — — — — — 275.32 4.561 0.151
27 46.8 — 6.5 3 2.4 0 0 1.4 4.3 B 1.22 0.292 1,204 37,856.6 347.50 4.550 0.189
28 45.3 — 6.5 2.9 2.5 0 0 1.5 3.8 B 1.23 0.292 1,204 38,053.1 446.20 5.810 0.212
29 49 — 6.5 3.2 2.7 0 0 0.6 4.3 B 1.35 0.292 1,204 37,866.6 149.20 1.950 0.081
30 51.9 — 8.2 4.3 3.7 0 0 0.9 3.8 B 1.85 0.292 1,204 29,871.9 197.30 3.280 0.121
31 44 — 5.8 2.5 2.2 0 0 1.1 4 B 1.11 0.259 1,259 33,775.4 264.60 3.460 0.134
32 46 — 6.4 2.9 2.7 0 0 6.4 3.8 B 1.37 0.289 1,209 37,638.4 1,814.90 23.650 0.876
33 46.1 — 6.4 3 2.8 0 0 1.8 4.3 B 1.4 0.289 1,209 37,468.9 441.50 5.780 0.239
34 60.2 — 10.9 6.6 6.6 0 0 2.6 5.2 C 2.64 0.383 1,049 38,733.2 564.10 9.470 0.466
35 — — — — — 17.9 51 21.1 66.1 C 2.07 0.46 784 20,260.4 298.20 10.010 3.985
36 — 8.8 — — — 0 0 0 0 A 0.8 0.226 3,027 46,476.3 328.60 6.260 0.000
37 — — — — — 20 75.1 22.4 92.7 C 2.16 0.55 639 20,118.5 260.60 10.140 4.877
38 — 11.3 — — — 1.2 4.8 0 0 B 1.04 0.289 2,798 59,684.2 442.70 8.430 0.000
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Table 19.7. US-287 facility analysis results.

Performance Measure Value
Free-Flow Travel Time (s) 1,571.8
Avg. Travel Time (s) 1,693.79
Avg. Speed (mi/h) 65.75
Vehicle Miles Traveled (veh-mi) 15,660.32
Vehicle Hours Traveled (veh-h) 244.907
Delay (veh-h) 19.839
Avg. Free-Flow Speed Delay (s/veh) 122.02
Avg. Free-Flow Speed Delay (%) 7.8
Avg. Threshold Delay (s/veh) 64.52
Avg. Threshold Delay (%) 4.1
LOS Score (Weighted Travel Time) 1.493
LOS Constancy 0.479
LOS Adjustment Factor 1.056
LOS Score (Weighted Travel Time and Adjusted) 1.577
Maximum d/c 0.781
Page 256
Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Suggested Citation: "19 Case Study: Montana US-287." National Academies of Sciences, Engineering, and Medicine. 2024. Reliability and Quality of Service Evaluation Methods for Rural Highways: A Guide. Washington, DC: The National Academies Press. doi: 10.17226/27895.
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Next Chapter: Appendix: Mitigation Strategies
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