Street Design Manual

Section 12.6.1 Stopping Sight Distance Where there are sight obstructions (such as walls, cut slopes, buildings and other hazards) on the inside of curves, changes in roadway alignment may be required to obtain adequate stopping sight distance if the sight obstruction cannot be removed.

Table 17 Stopping Sight Distance

Minimum stopping sight distance (in feet), Street grade in percent

Speed limit (mph)

Upgrades

Flat

Downgrades

9% 140 180 225 270 320 375

6% 145 185 230 280 330 390

3% 150 200 240 290 345 405

0% 150 200 250 305 360 425

-3% 155 210 265 315 380 450

-6% 165 215 275 335 400 475

-9% 175 230 290 355 430 510

25 30 35 40 45 50

Figure 6Sight Distance Measurement

Raleigh Street Design Manual – Page 101