To provide bicyclists with an opportunity to see and react to the unexpected,

a shared use path should be designed with adequate stopping

sight distances. The distance required to bring a bicycle to a full controlled

stop is a function of the bicyclist’s perception and brake reaction

time, the initial speed of the bicycle, the coefficient of friction between

the tires and the pavement, and the braking ability of the bicycle.

Figure 19 indicates the minimum stopping sight distance for various design

speeds and grades based on a total perception and brake reaction

time of 2.5 seconds and a coefficient of friction of 0.25 to account for the

poor wet weather braking characteristics of many bicycles. For two-way

shared use paths, the sight distance in the descending direction, that is,

where “G” is negative, will control the design.

Table 3 is used to select the minimum length of vertical curve necessary

to provide minimum stopping sight distance at various speeds on crest

vertical curves. The eye height of the bicyclist is assumed to be 1400mm

(4 1/2 feet) and the object height is assumed to be 0 mm (0 inches) to recognize

that impediments to bicycle travel exist at pavement level.

Table 4 indicates the minimum clearance that should be used for line of

sight obstructions for horizontal curves. The lateral clearance is obtained

by entering Table 4 with the stopping sight distance from Figure 19 and

the proposed horizontal radius of curvature.

Bicyclists frequently ride side-by-side on shared use paths, and on narrow

paths bicyclists have a tendency to ride near the middle of the path. For

these reasons, and because of the higher potential for bicycle crashes, lateral

clearances on horizontal curves should be calculated based on the sum

of the stopping sight distances for bicyclists traveling in opposite directions

around the curve. Where this is not possible or feasible, consideration

should be given to widening the path through the curve, installing a yellow

center line stripe, installing a “Curve Ahead” warning sign in accordance

with the MUTCD 2, or some combination of these alternatives.

S =

V

254 (f G)

V

1.4

2

±

+

Where: S = stopping sight distance (m)

V = velocity (km/h)

f = coefficient of friction (use 0.25)

G = grade (m/m) (rise/run)

Descend - - - - - -

Ascend

Descend - - - - - -

Ascend

S =

V

30 (f G)

3.67V

2

±

+

Where: S = stopping sight distance (ft)

V = velocity (mph)

f = coefficient of friction (use 0.25)

G = grade (ft/ft) (rise/run)

3 7 17 27 37 47 57 67 77 87 97 107

4 10 20 30 40 50 60 70 80 91 103 116 129 143

5 4 14 24 34 44 54 64 75 88 100 114 129 145 161 179

6 3 13 23 33 43 54 65 77 91 105 121 137 155 174 193 214

7 10 20 30 40 51 63 76 90 106 123 141 160 181 203 226 250

8 5 15 25 35 46 58 71 86 103 121 140 161 183 206 231 258 286

9 9 19 29 39 51 65 80 97 116 136 158 181 206 232 260 290 321

10 2 12 22 32 44 57 72 89 108 129 151 175 201 229 258 289 322 357

11 5 15 25 35 48 63 80 98 119 141 166 193 221 251 284 318 355 393

12 7 17 27 39 53 69 87 107 130 154 181 210 241 274 310 347 387 429

13 8 18 29 42 57 74 94 116 140 167 196 228 261 297 335 376 419 464

14 10 20 31 45 61 80 101 125 151 180 211 245 281 320 361 405 451 500

15 1 11 21 33 48 66 86 108 134 162 193 226 263 301 343 387 434 483 536

16 3 13 23 36 51 70 91 116 143 173 206 241 280 321 366 413 463 516 571

17 4 14 24 38 55 74 97 123 152 184 219 257 298 342 389 439 492 548 607

18 4 14 26 40 58 79 103 130 161 194 231 272 315 362 411 464 521 580 643

19 5 15 27 42 61 83 109 137 170 205 244 287 333 382 434 490 550 612 679

20 6 16 29 45 64 88 114 145 179 216 257 302 350 402 457 516 579 645 714

21 7 17 30 47 68 92 120 152 188 227 270 317 368 422 480 542 608 677 750

22 7 18 31 49 71 96 126 159 196 238 283 281 385 442 503 568 636 709 786

23 8 18 33 51 74 101 131 166 205 248 296 347 403 462 526 593 665 741 821

24 8 19 34 54 77 105 137 174 214 259 309 362 420 482 549 619 694 774 857

25 9 20 36 56 80 109 143 181 223 270 321 377 438 502 571 645 723 806 893

when S > L L =2S-

280

A

when S < L L =

AS2

280

Height of cyclist eye - 1400 mm

Height of object - 0 mm

Shaded area represents S = L

L = Minimum Length of Vertical Curve (m)

A = Algebraic Grade Difference (%)

S = Stopping Sight Distance (m)

Minimum Length of Vertical Curve = 1 m

2 30 70 110 150

3 20 60 100 140 180 220 260 300

4 15 55 95 135 175 215 256 300 348 400

5 20 60 100 140 180 222 269 320 376 436 500

6 10 50 90 130 171 216 267 323 384 451 523 600

7 31 71 111 152 199 252 311 376 448 526 610 700

8 8 48 88 128 174 228 288 356 430 512 601 697 800

9 20 60 100 144 196 256 324 400 484 576 676 784 900

10 30 70 111 160 218 284 360 444 538 640 751 871 1000

11 38 78 122 176 240 313 396 489 592 704 826 958 1100

12 5 45 85 133 192 261 341 432 533 645 768 901 1045 1200

13 11 51 92 144 208 283 370 468 578 699 832 976 1132 1300

14 16 56 100 156 224 305 398 504 622 753 896 1052 1220 1400

15 20 60 107 167 240 327 427 540 667 807 960 1127 1307 1500

16 24 64 114 178 256 348 455 576 711 860 1024 1202 1394 1600

17 27 68 121 189 272 370 484 612 756 914 1088 1277 1481 1700

18 30 72 128 200 288 392 512 648 800 968 1152 1352 1568 1800

19 33 76 135 211 304 414 540 684 844 1022 1216 1427 1655 1900

20 35 80 142 222 320 436 569 720 889 1076 1280 1502 1742 2000

21 37 84 149 233 336 457 597 756 933 1129 1344 1577 1829 2100

22 39 88 156 244 352 479 626 792 978 1183 1408 1652 1916 2200

23 41 92 164 256 368 501 654 828 1022 1237 1472 1728 2004 2300

24 3 43 96 171 267 384 523 683 864 1067 1291 1536 1803 2091 2400

25 4 44 100 177 278 400 544 711 900 1111 1344 1600 1878 2178 2500

A

900

Height of cyclist’s eye – 4 1/2 ft

Height of object – 0 ft

Shaded area represents S = L

L = Minimum Length of Vertical Curve (ft)

A = Algebraic Grade Difference (%)

S = Stopping Sight Distance (ft)

Minimum Length of Vertical Curve = 3 ft.

For Metric Units: For English Units:

S = Stopping Sight Distance (m) S = Stopping Sight Distance (ft)

R = Radius of centerline of lane (m) R = Radius of centerline of lane (ft)

M = Distance from centerline of

lane to obstruction (m)

M = Distance from centerline of

lane to obstruction (ft)

10 1.2 2.7 4.6 6.8 9.3

15 0.8 1.8 3.2 4.9 6.9 9.1 11 14

20 0.6 1.4 2.4 3.8 5.4 7.2 9.2 11 14 16 19

25 0.5 1.1 2 3.1 4.4 5.9 7.6 9.5 11 14 16 18 21 23

50 0.3 0.6 1 1.6 2.2 3 3.9 5 6.1 7.4 8.7 10 12 13 15 17 19 21 23

75 0.2 0.4 0.7 1 1.5 2 2.7 3.4 4.1 5 5.9 6.9 8 9.2 10 12 13 15 16

100 0.1 0.3 0.5 0.8 1.1 1.5 2 2.5 3.1 3.8 4.5 5.2 6.1 7 7.9 8.9 10 11 12

125 0.1 0.2 0.4 0.6 0.9 1.2 1.6 2 2.5 3 3.6 4.2 4.9 5.6 6.3 7.2 8 8.9 9.9

150 0.2 0.3 0.5 0.7 1 1.3 1.7 2.1 2.5 3 3.5 4.1 4.7 5.3 6 6.7 7.5 8.3

175 0.2 0.3 0.4 0.6 0.9 1.1 1.4 1.8 2.2 2.6 3 3.5 4 4.6 5.1 5.8 6.4 7.1

200 0.1 0.3 0.4 0.6 0.8 1 1.3 1.6 1.9 2.2 2.6 3.1 3.5 4 4.5 5 5.6 6.2

225 0.1 0.2 0.3 0.5 0.7 0.9 1.1 1.4 1.7 2 2.3 2.7 3.1 3.5 4 4.5 5 5.5

250 0.1 0.2 0.3 0.5 0.6 0.8 1 1.2 1.5 1.8 2.1 2.4 2.8 3.2 3.6 4 4.5 5

275 0.1 0.2 0.3 0.4 0.6 0.7 0.9 1.1 1.4 1.6 1.9 2.2 2.6 2.9 3.3 3.7 4.1 4.5

300 0.2 0.3 0.4 0.5 0.7 0.8 1 1.3 1.5 1.8 2 2.3 2.7 3 3.4 3.8 4.2

Intersections between paths and roadways are often the most critical issue

in shared use path design. Due to the potential conflicts at these

junctions, careful design is of paramount importance to the safety of path

users and motorists alike. The solutions provided in this chapter should

be considered guidelines, not absolutes. Each intersection is unique and

will require sound engineering judgment on the part of the designer as to

the appropriate solution.

There are three basic categories of path-roadway intersections:

midblock, adjacent path and complex. The following discussion provides

guidance for each of these categories. Each of these intersection

types may cross any number of roadway lanes, divided or undivided,

with varying speeds and volumes of motor vehicle traffic, and may be

uncontrolled, or more typically, sign or signal controlled. Only at-grade

crossings are addressed in this section.

50 1.0 3.9 8.7 15.2 23.0 31.9 41.5

75 0.7 2.7 5.9 10.4 16.1 22.8 30.4 38.8 47.8 57.4 67.2

95 0.5 2.1 4.7 8.3 12.9 18.3 24.7 31.8 39.5 48.0 56.9 66.3 75.9 85.8

125 0.4 1.6 3.6 6.3 9.9 14.1 19.1 24.7 31.0 37.9 45.4 53.3 61.7 70.6 79.7

155 0.3 1.3 2.9 5.1 8.0 11.5 15.5 20.2 25.4 31.2 37.4 44.2 51.4 59.1 67.1

175 0.3 1.1 2.6 4.6 7.1 10.2 13.8 18.0 22.6 27.8 33.5 39.6 46.1 53.1 60.5

200 0.3 1.0 2.2 4.0 6.2 8.9 12.1 15.8 19.9 24.5 29.5 34.9 40.8 47.0 53.7

225 0.2 0.9 2.0 3.5 5.5 8.0 10.8 14.1 17.8 21.9 26.4 31.3 36.5 42.2 48.2

250 0.2 0.8 1.8 3.2 5.0 7.2 9.7 12.7 16.0 19.7 23.8 28.3 33.1 38.2 43.7

275 0.2 0.7 1.6 2.9 4.5 6.5 8.9 11.6 14.6 18.0 21.7 25.8 30.2 34.9 39.9

300 0.2 0.7 1.5 2.7 4.2 6.0 8.1 10.6 13.4 16.5 19.9 23.7 27.7 32.1 36.7

350 0.1 0.6 1.3 2.3 3.6 5.1 7.0 9.1 11.5 14.2 17.1 20.4 23.9 27.6 31.7

390 0.1 0.5 1.2 2.1 3.2 4.6 6.3 8.2 10.3 12.8 15.4 18.3 21.5 24.9 28.5

500 0.1 0.4 0.9 1.6 2.5 3.6 4.9 6.4 8.1 10.0 12.1 14.3 16.8 19.5 22.3

565 0.4 0.8 1.4 2.2 3.2 4.3 5.7 7.2 8.8 10.7 12.7 14.9 17.3 19.8

600 0.3 0.8 1.3 2.1 3.0 4.1 5.3 6.7 8.3 10.1 12.0 14.0 16.3 18.7

700 0.3 0.6 1.1 1.8 2.6 3.5 4.6 5.8 7.1 8.6 10.3 12.0 14.0 16.0

800 0.3 0.6 1.0 1.6 2.2 3.1 4.0 5.1 6.2 7.6 9.0 10.5 12.2 14.0

900 0.2 0.5 0.9 1.4 2.0 2.7 3.6 4.5 5.6 6.7 8.0 9.4 10.9 12.5

1000 0.2 0.5 0.8 1.3 1.8 2.4 3.2 4.0 5.0 6.0 7.2 8.4 9.8 11.2